Merge branch 'for-5.1/hid-uclogic' into for-linus

hid-uclogic driver revamp, in order to support wider range of Huion
tablets, from Nikolai Kondrashov

drivers/hid/Kconfig

@@ -412,6 +412,12 @@ config HID_WALTOP
 	---help---
 	Support for Waltop tablets.
 
+config HID_VIEWSONIC
+	tristate "ViewSonic/Signotec"
+	depends on HID
+	help
+	  Support for ViewSonic/Signotec PD1011 signature pad.
+
 config HID_GYRATION
 	tristate "Gyration remote control"
 	depends on HID

drivers/hid/Makefile

@@ -109,12 +109,16 @@ obj-$(CONFIG_HID_THRUSTMASTER)	+= hid-tmff.o
 obj-$(CONFIG_HID_TIVO)		+= hid-tivo.o
 obj-$(CONFIG_HID_TOPSEED)	+= hid-topseed.o
 obj-$(CONFIG_HID_TWINHAN)	+= hid-twinhan.o
+hid-uclogic-objs		:= hid-uclogic-core.o \
+				   hid-uclogic-rdesc.o \
+				   hid-uclogic-params.o
 obj-$(CONFIG_HID_UCLOGIC)	+= hid-uclogic.o
 obj-$(CONFIG_HID_UDRAW_PS3)	+= hid-udraw-ps3.o
 obj-$(CONFIG_HID_LED)		+= hid-led.o
 obj-$(CONFIG_HID_XINMO)		+= hid-xinmo.o
 obj-$(CONFIG_HID_ZEROPLUS)	+= hid-zpff.o
 obj-$(CONFIG_HID_ZYDACRON)	+= hid-zydacron.o
+obj-$(CONFIG_HID_VIEWSONIC)	+= hid-viewsonic.o
 
 wacom-objs			:= wacom_wac.o wacom_sys.o
 obj-$(CONFIG_HID_WACOM)		+= wacom.o

drivers/hid/hid-ids.h

@@ -663,6 +663,7 @@
 #define USB_DEVICE_ID_KYE_MOUSEPEN_I608X_V2	0x501a
 #define USB_DEVICE_ID_KYE_EASYPEN_M610X	0x5013
 #define USB_DEVICE_ID_KYE_PENSKETCH_M912	0x5015
+#define USB_DEVICE_ID_KYE_EASYPEN_M406XE	0x5019
 
 #define USB_VENDOR_ID_LABTEC		0x1020
 #define USB_DEVICE_ID_LABTEC_WIRELESS_KEYBOARD	0x0006
@@ -1138,11 +1139,16 @@
 #define USB_DEVICE_ID_UCLOGIC_WIRELESS_TABLET_TWHL850	0x0522
 #define USB_DEVICE_ID_UCLOGIC_TABLET_TWHA60	0x0781
 #define USB_DEVICE_ID_UCLOGIC_DRAWIMAGE_G3	0x3031
-#define USB_DEVICE_ID_UGEE_TABLET_81		0x0081
-#define USB_DEVICE_ID_UGEE_TABLET_45		0x0045
+#define USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_81	0x0081
+#define USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_45	0x0045
+#define USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_47	0x0047
 #define USB_DEVICE_ID_YIYNOVA_TABLET		0x004d
 
 #define USB_VENDOR_ID_UGEE		0x28bd
+#define USB_DEVICE_ID_UGEE_XPPEN_TABLET_G540	0x0075
+#define USB_DEVICE_ID_UGEE_XPPEN_TABLET_G640	0x0094
+#define USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO01	0x0042
+#define USB_DEVICE_ID_UGEE_TABLET_G5		0x0074
 #define USB_DEVICE_ID_UGEE_TABLET_EX07S		0x0071
 
 #define USB_VENDOR_ID_UNITEC	0x227d
@@ -1244,4 +1250,10 @@
 #define USB_VENDOR_ID_UGTIZER			0x2179
 #define USB_DEVICE_ID_UGTIZER_TABLET_GP0610	0x0053
 
+#define USB_VENDOR_ID_VIEWSONIC			0x0543
+#define USB_DEVICE_ID_VIEWSONIC_PD1011		0xe621
+
+#define USB_VENDOR_ID_SIGNOTEC			0x2133
+#define USB_DEVICE_ID_SIGNOTEC_VIEWSONIC_PD1011	0x0018
+
 #endif

drivers/hid/hid-kye.c

@@ -483,6 +483,80 @@ static __u8 pensketch_m912_rdesc_fixed[] = {
 	0xC0                          /*  End Collection                  */
 };
 
+/* Original EasyPen M406XE report descriptor size */
+#define EASYPEN_M406XE_RDESC_ORIG_SIZE	476
+
+/* Fixed EasyPen M406XE  report descriptor */
+static __u8 easypen_m406xe_rdesc_fixed[] = {
+	0x05, 0x01,         /*  Usage Page (Desktop),               */
+	0x09, 0x01,         /*  Usage (01h),                        */
+	0xA1, 0x01,         /*  Collection (Application),           */
+	0x85, 0x05,         /*      Report ID (5),                  */
+	0x09, 0x01,         /*      Usage (01h),                    */
+	0x15, 0x80,         /*      Logical Minimum (-128),         */
+	0x25, 0x7F,         /*      Logical Maximum (127),          */
+	0x75, 0x08,         /*      Report Size (8),                */
+	0x95, 0x07,         /*      Report Count (7),               */
+	0xB1, 0x02,         /*      Feature (Variable),             */
+	0xC0,               /*  End Collection,                     */
+	0x05, 0x0D,         /*  Usage Page (Digitizer),             */
+	0x09, 0x02,         /*  Usage (Pen),                        */
+	0xA1, 0x01,         /*  Collection (Application),           */
+	0x85, 0x10,         /*      Report ID (16),                 */
+	0x09, 0x20,         /*      Usage (Stylus),                 */
+	0xA0,               /*      Collection (Physical),          */
+	0x14,               /*          Logical Minimum (0),        */
+	0x25, 0x01,         /*          Logical Maximum (1),        */
+	0x75, 0x01,         /*          Report Size (1),            */
+	0x09, 0x42,         /*          Usage (Tip Switch),         */
+	0x09, 0x44,         /*          Usage (Barrel Switch),      */
+	0x09, 0x46,         /*          Usage (Tablet Pick),        */
+	0x95, 0x03,         /*          Report Count (3),           */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0x95, 0x04,         /*          Report Count (4),           */
+	0x81, 0x03,         /*          Input (Constant, Variable), */
+	0x09, 0x32,         /*          Usage (In Range),           */
+	0x95, 0x01,         /*          Report Count (1),           */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0x75, 0x10,         /*          Report Size (16),           */
+	0x95, 0x01,         /*          Report Count (1),           */
+	0xA4,               /*          Push,                       */
+	0x05, 0x01,         /*          Usage Page (Desktop),       */
+	0x55, 0xFD,         /*          Unit Exponent (-3),         */
+	0x65, 0x13,         /*          Unit (Inch),                */
+	0x34,               /*          Physical Minimum (0),       */
+	0x09, 0x30,         /*          Usage (X),                  */
+	0x46, 0x70, 0x17,   /*          Physical Maximum (6000),    */
+	0x26, 0x00, 0x3C,   /*          Logical Maximum (15360),    */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0x09, 0x31,         /*          Usage (Y),                  */
+	0x46, 0xA0, 0x0F,   /*          Physical Maximum (4000),    */
+	0x26, 0x00, 0x28,   /*          Logical Maximum (10240),    */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0xB4,               /*          Pop,                        */
+	0x09, 0x30,         /*          Usage (Tip Pressure),       */
+	0x26, 0xFF, 0x03,   /*          Logical Maximum (1023),     */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0xC0,               /*      End Collection,                 */
+	0xC0,               /*  End Collection                      */
+	0x05, 0x0C,         /*  Usage Page (Consumer),              */
+	0x09, 0x01,         /*  Usage (Consumer Control),           */
+	0xA1, 0x01,         /*  Collection (Application),           */
+	0x85, 0x12,         /*      Report ID (18),                 */
+	0x14,               /*      Logical Minimum (0),            */
+	0x25, 0x01,         /*      Logical Maximum (1),            */
+	0x75, 0x01,         /*      Report Size (1),                */
+	0x95, 0x04,         /*      Report Count (4),               */
+	0x0A, 0x79, 0x02,   /*      Usage (AC Redo Or Repeat),      */
+	0x0A, 0x1A, 0x02,   /*      Usage (AC Undo),                */
+	0x0A, 0x2D, 0x02,   /*      Usage (AC Zoom In),             */
+	0x0A, 0x2E, 0x02,   /*      Usage (AC Zoom Out),            */
+	0x81, 0x02,         /*      Input (Variable),               */
+	0x95, 0x34,         /*      Report Count (52),              */
+	0x81, 0x03,         /*      Input (Constant, Variable),     */
+	0xC0                /*  End Collection                      */
+};
+
 static __u8 *kye_consumer_control_fixup(struct hid_device *hdev, __u8 *rdesc,
 		unsigned int *rsize, int offset, const char *device_name) {
 	/*
@@ -555,6 +629,12 @@ static __u8 *kye_report_fixup(struct hid_device *hdev, __u8 *rdesc,
 			*rsize = sizeof(easypen_m610x_rdesc_fixed);
 		}
 		break;
+	case USB_DEVICE_ID_KYE_EASYPEN_M406XE:
+		if (*rsize == EASYPEN_M406XE_RDESC_ORIG_SIZE) {
+			rdesc = easypen_m406xe_rdesc_fixed;
+			*rsize = sizeof(easypen_m406xe_rdesc_fixed);
+		}
+		break;
 	case USB_DEVICE_ID_KYE_PENSKETCH_M912:
 		if (*rsize == PENSKETCH_M912_RDESC_ORIG_SIZE) {
 			rdesc = pensketch_m912_rdesc_fixed;
@@ -644,6 +724,7 @@ static int kye_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	case USB_DEVICE_ID_KYE_MOUSEPEN_I608X:
 	case USB_DEVICE_ID_KYE_MOUSEPEN_I608X_V2:
 	case USB_DEVICE_ID_KYE_EASYPEN_M610X:
+	case USB_DEVICE_ID_KYE_EASYPEN_M406XE:
 	case USB_DEVICE_ID_KYE_PENSKETCH_M912:
 		ret = kye_tablet_enable(hdev);
 		if (ret) {
@@ -678,6 +759,8 @@ static const struct hid_device_id kye_devices[] = {
 				USB_DEVICE_ID_KYE_MOUSEPEN_I608X_V2) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE,
 				USB_DEVICE_ID_KYE_EASYPEN_M610X) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE,
+				USB_DEVICE_ID_KYE_EASYPEN_M406XE) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE,
 				USB_DEVICE_ID_GENIUS_GILA_GAMING_MOUSE) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE,

drivers/hid/hid-quirks.c

@@ -99,6 +99,7 @@ static const struct hid_device_id hid_quirks[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_MOUSEPEN_I608X), HID_QUIRK_MULTI_INPUT },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_MOUSEPEN_I608X_V2), HID_QUIRK_MULTI_INPUT },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_PENSKETCH_M912), HID_QUIRK_MULTI_INPUT },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_EASYPEN_M406XE), HID_QUIRK_MULTI_INPUT },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_PIXART_USB_OPTICAL_MOUSE_ID2), HID_QUIRK_ALWAYS_POLL },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_LOGITECH_C007), HID_QUIRK_ALWAYS_POLL },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_LOGITECH_C077), HID_QUIRK_ALWAYS_POLL },
@@ -411,11 +412,6 @@ static const struct hid_device_id hid_have_special_driver[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_GENIUS_MANTICORE) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_GENIUS_GX_IMPERATOR) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_ERGO_525V) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_EASYPEN_I405X) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_MOUSEPEN_I608X) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_MOUSEPEN_I608X_V2) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_EASYPEN_M610X) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_PENSKETCH_M912) },
 #endif
 #if IS_ENABLED(CONFIG_HID_LCPOWER)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_LCPOWER, USB_DEVICE_ID_LCPOWER_LC1000) },
@@ -674,35 +670,9 @@ static const struct hid_device_id hid_have_special_driver[] = {
 #if IS_ENABLED(CONFIG_HID_TWINHAN)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_TWINHAN, USB_DEVICE_ID_TWINHAN_IR_REMOTE) },
 #endif
-#if IS_ENABLED(CONFIG_HID_UCLOGIC)
-	{ HID_USB_DEVICE(USB_VENDOR_ID_HUION, USB_DEVICE_ID_HUION_TABLET) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_HUION_TABLET) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UCLOGIC_TABLET_PF1209) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UCLOGIC_TABLET_WP4030U) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UCLOGIC_TABLET_WP5540U) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UCLOGIC_TABLET_WP8060U) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UCLOGIC_TABLET_WP1062) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UCLOGIC_WIRELESS_TABLET_TWHL850) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UCLOGIC_TABLET_TWHA60) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_YIYNOVA_TABLET) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UGEE_TABLET_81) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UGEE_TABLET_45) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UCLOGIC_DRAWIMAGE_G3) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE, USB_DEVICE_ID_UGEE_TABLET_EX07S) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UGTIZER, USB_DEVICE_ID_UGTIZER_TABLET_GP0610) },
-#endif
 #if IS_ENABLED(CONFIG_HID_UDRAW_PS3)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_THQ, USB_DEVICE_ID_THQ_PS3_UDRAW) },
 #endif
-#if IS_ENABLED(CONFIG_HID_WALTOP)
-	{ HID_USB_DEVICE(USB_VENDOR_ID_WALTOP, USB_DEVICE_ID_WALTOP_SLIM_TABLET_5_8_INCH) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_WALTOP, USB_DEVICE_ID_WALTOP_SLIM_TABLET_12_1_INCH) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_WALTOP, USB_DEVICE_ID_WALTOP_Q_PAD) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_WALTOP, USB_DEVICE_ID_WALTOP_PID_0038) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_WALTOP, USB_DEVICE_ID_WALTOP_MEDIA_TABLET_10_6_INCH) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_WALTOP, USB_DEVICE_ID_WALTOP_MEDIA_TABLET_14_1_INCH) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_WALTOP, USB_DEVICE_ID_WALTOP_SIRIUS_BATTERY_FREE_TABLET) },
-#endif
 #if IS_ENABLED(CONFIG_HID_XINMO)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_XIN_MO, USB_DEVICE_ID_XIN_MO_DUAL_ARCADE) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_XIN_MO, USB_DEVICE_ID_THT_2P_ARCADE) },

drivers/hid/hid-uclogic-core.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  HID driver for UC-Logic devices not fully compliant with HID standard
+ *
+ *  Copyright (c) 2010-2014 Nikolai Kondrashov
+ *  Copyright (c) 2013 Martin Rusko
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include "usbhid/usbhid.h"
+#include "hid-uclogic-params.h"
+
+#include "hid-ids.h"
+
+/* Driver data */
+struct uclogic_drvdata {
+	/* Interface parameters */
+	struct uclogic_params params;
+	/* Pointer to the replacement report descriptor. NULL if none. */
+	__u8 *desc_ptr;
+	/*
+	 * Size of the replacement report descriptor.
+	 * Only valid if desc_ptr is not NULL
+	 */
+	unsigned int desc_size;
+	/* Pen input device */
+	struct input_dev *pen_input;
+	/* In-range timer */
+	struct timer_list inrange_timer;
+	/* Last rotary encoder state, or U8_MAX for none */
+	u8 re_state;
+};
+
+/**
+ * uclogic_inrange_timeout - handle pen in-range state timeout.
+ * Emulate input events normally generated when pen goes out of range for
+ * tablets which don't report that.
+ *
+ * @t:	The timer the timeout handler is attached to, stored in a struct
+ *	uclogic_drvdata.
+ */
+static void uclogic_inrange_timeout(struct timer_list *t)
+{
+	struct uclogic_drvdata *drvdata = from_timer(drvdata, t,
+							inrange_timer);
+	struct input_dev *input = drvdata->pen_input;
+
+	if (input == NULL)
+		return;
+	input_report_abs(input, ABS_PRESSURE, 0);
+	/* If BTN_TOUCH state is changing */
+	if (test_bit(BTN_TOUCH, input->key)) {
+		input_event(input, EV_MSC, MSC_SCAN,
+				/* Digitizer Tip Switch usage */
+				0xd0042);
+		input_report_key(input, BTN_TOUCH, 0);
+	}
+	input_report_key(input, BTN_TOOL_PEN, 0);
+	input_sync(input);
+}
+
+static __u8 *uclogic_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+					unsigned int *rsize)
+{
+	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
+
+	if (drvdata->desc_ptr != NULL) {
+		rdesc = drvdata->desc_ptr;
+		*rsize = drvdata->desc_size;
+	}
+	return rdesc;
+}
+
+static int uclogic_input_mapping(struct hid_device *hdev,
+				 struct hid_input *hi,
+				 struct hid_field *field,
+				 struct hid_usage *usage,
+				 unsigned long **bit,
+				 int *max)
+{
+	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
+	struct uclogic_params *params = &drvdata->params;
+
+	/* discard the unused pen interface */
+	if (params->pen_unused && (field->application == HID_DG_PEN))
+		return -1;
+
+	/* let hid-core decide what to do */
+	return 0;
+}
+
+static int uclogic_input_configured(struct hid_device *hdev,
+		struct hid_input *hi)
+{
+	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
+	struct uclogic_params *params = &drvdata->params;
+	char *name;
+	const char *suffix = NULL;
+	struct hid_field *field;
+	size_t len;
+
+	/* no report associated (HID_QUIRK_MULTI_INPUT not set) */
+	if (!hi->report)
+		return 0;
+
+	/*
+	 * If this is the input corresponding to the pen report
+	 * in need of tweaking.
+	 */
+	if (hi->report->id == params->pen.id) {
+		/* Remember the input device so we can simulate events */
+		drvdata->pen_input = hi->input;
+	}
+
+	field = hi->report->field[0];
+
+	switch (field->application) {
+	case HID_GD_KEYBOARD:
+		suffix = "Keyboard";
+		break;
+	case HID_GD_MOUSE:
+		suffix = "Mouse";
+		break;
+	case HID_GD_KEYPAD:
+		suffix = "Pad";
+		break;
+	case HID_DG_PEN:
+		suffix = "Pen";
+		break;
+	case HID_CP_CONSUMER_CONTROL:
+		suffix = "Consumer Control";
+		break;
+	case HID_GD_SYSTEM_CONTROL:
+		suffix = "System Control";
+		break;
+	}
+
+	if (suffix) {
+		len = strlen(hdev->name) + 2 + strlen(suffix);
+		name = devm_kzalloc(&hi->input->dev, len, GFP_KERNEL);
+		if (name) {
+			snprintf(name, len, "%s %s", hdev->name, suffix);
+			hi->input->name = name;
+		}
+	}
+
+	return 0;
+}
+
+static int uclogic_probe(struct hid_device *hdev,
+		const struct hid_device_id *id)
+{
+	int rc;
+	struct uclogic_drvdata *drvdata = NULL;
+	bool params_initialized = false;
+
+	/*
+	 * libinput requires the pad interface to be on a different node
+	 * than the pen, so use QUIRK_MULTI_INPUT for all tablets.
+	 */
+	hdev->quirks |= HID_QUIRK_MULTI_INPUT;
+
+	/* Allocate and assign driver data */
+	drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
+	if (drvdata == NULL) {
+		rc = -ENOMEM;
+		goto failure;
+	}
+	timer_setup(&drvdata->inrange_timer, uclogic_inrange_timeout, 0);
+	drvdata->re_state = U8_MAX;
+	hid_set_drvdata(hdev, drvdata);
+
+	/* Initialize the device and retrieve interface parameters */
+	rc = uclogic_params_init(&drvdata->params, hdev);
+	if (rc != 0) {
+		hid_err(hdev, "failed probing parameters: %d\n", rc);
+		goto failure;
+	}
+	params_initialized = true;
+	hid_dbg(hdev, "parameters:\n" UCLOGIC_PARAMS_FMT_STR,
+		UCLOGIC_PARAMS_FMT_ARGS(&drvdata->params));
+	if (drvdata->params.invalid) {
+		hid_info(hdev, "interface is invalid, ignoring\n");
+		rc = -ENODEV;
+		goto failure;
+	}
+
+	/* Generate replacement report descriptor */
+	rc = uclogic_params_get_desc(&drvdata->params,
+				     &drvdata->desc_ptr,
+				     &drvdata->desc_size);
+	if (rc) {
+		hid_err(hdev,
+			"failed generating replacement report descriptor: %d\n",
+			rc);
+		goto failure;
+	}
+
+	rc = hid_parse(hdev);
+	if (rc) {
+		hid_err(hdev, "parse failed\n");
+		goto failure;
+	}
+
+	rc = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (rc) {
+		hid_err(hdev, "hw start failed\n");
+		goto failure;
+	}
+
+	return 0;
+failure:
+	/* Assume "remove" might not be called if "probe" failed */
+	if (params_initialized)
+		uclogic_params_cleanup(&drvdata->params);
+	return rc;
+}
+
+#ifdef CONFIG_PM
+static int uclogic_resume(struct hid_device *hdev)
+{
+	int rc;
+	struct uclogic_params params;
+
+	/* Re-initialize the device, but discard parameters */
+	rc = uclogic_params_init(&params, hdev);
+	if (rc != 0)
+		hid_err(hdev, "failed to re-initialize the device\n");
+	else
+		uclogic_params_cleanup(&params);
+
+	return rc;
+}
+#endif
+
+static int uclogic_raw_event(struct hid_device *hdev,
+				struct hid_report *report,
+				u8 *data, int size)
+{
+	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
+	struct uclogic_params *params = &drvdata->params;
+
+	/* Tweak pen reports, if necessary */
+	if (!params->pen_unused &&
+	    (report->type == HID_INPUT_REPORT) &&
+	    (report->id == params->pen.id) &&
+	    (size >= 2)) {
+		/* If it's the "virtual" frame controls report */
+		if (params->frame.id != 0 &&
+		    data[1] & params->pen_frame_flag) {
+			/* Change to virtual frame controls report ID */
+			data[0] = params->frame.id;
+			return 0;
+		}
+		/* If in-range reports are inverted */
+		if (params->pen.inrange ==
+			UCLOGIC_PARAMS_PEN_INRANGE_INVERTED) {
+			/* Invert the in-range bit */
+			data[1] ^= 0x40;
+		}
+		/*
+		 * If report contains fragmented high-resolution pen
+		 * coordinates
+		 */
+		if (size >= 10 && params->pen.fragmented_hires) {
+			u8 pressure_low_byte;
+			u8 pressure_high_byte;
+
+			/* Lift pressure bytes */
+			pressure_low_byte = data[6];
+			pressure_high_byte = data[7];
+			/*
+			 * Move Y coord to make space for high-order X
+			 * coord byte
+			 */
+			data[6] = data[5];
+			data[5] = data[4];
+			/* Move high-order X coord byte */
+			data[4] = data[8];
+			/* Move high-order Y coord byte */
+			data[7] = data[9];
+			/* Place pressure bytes */
+			data[8] = pressure_low_byte;
+			data[9] = pressure_high_byte;
+		}
+		/* If we need to emulate in-range detection */
+		if (params->pen.inrange == UCLOGIC_PARAMS_PEN_INRANGE_NONE) {
+			/* Set in-range bit */
+			data[1] |= 0x40;
+			/* (Re-)start in-range timeout */
+			mod_timer(&drvdata->inrange_timer,
+					jiffies + msecs_to_jiffies(100));
+		}
+	}
+
+	/* Tweak frame control reports, if necessary */
+	if ((report->type == HID_INPUT_REPORT) &&
+	    (report->id == params->frame.id)) {
+		/* If need to, and can, set pad device ID for Wacom drivers */
+		if (params->frame.dev_id_byte > 0 &&
+		    params->frame.dev_id_byte < size) {
+			data[params->frame.dev_id_byte] = 0xf;
+		}
+		/* If need to, and can, read rotary encoder state change */
+		if (params->frame.re_lsb > 0 &&
+		    params->frame.re_lsb / 8 < size) {
+			unsigned int byte = params->frame.re_lsb / 8;
+			unsigned int bit = params->frame.re_lsb % 8;
+
+			u8 change;
+			u8 prev_state = drvdata->re_state;
+			/* Read Gray-coded state */
+			u8 state = (data[byte] >> bit) & 0x3;
+			/* Encode state change into 2-bit signed integer */
+			if ((prev_state == 1 && state == 0) ||
+			    (prev_state == 2 && state == 3)) {
+				change = 1;
+			} else if ((prev_state == 2 && state == 0) ||
+				   (prev_state == 1 && state == 3)) {
+				change = 3;
+			} else {
+				change = 0;
+			}
+			/* Write change */
+			data[byte] = (data[byte] & ~((u8)3 << bit)) |
+					(change << bit);
+			/* Remember state */
+			drvdata->re_state = state;
+		}
+	}
+
+	return 0;
+}
+
+static void uclogic_remove(struct hid_device *hdev)
+{
+	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
+
+	del_timer_sync(&drvdata->inrange_timer);
+	hid_hw_stop(hdev);
+	kfree(drvdata->desc_ptr);
+	uclogic_params_cleanup(&drvdata->params);
+}
+
+static const struct hid_device_id uclogic_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_TABLET_PF1209) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_TABLET_WP4030U) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_TABLET_WP5540U) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_TABLET_WP8060U) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_TABLET_WP1062) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_WIRELESS_TABLET_TWHL850) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_TABLET_TWHA60) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_HUION,
+				USB_DEVICE_ID_HUION_TABLET) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_HUION_TABLET) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_YIYNOVA_TABLET) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_81) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_45) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_47) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
+				USB_DEVICE_ID_UCLOGIC_DRAWIMAGE_G3) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UGTIZER,
+				USB_DEVICE_ID_UGTIZER_TABLET_GP0610) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
+				USB_DEVICE_ID_UGEE_TABLET_G5) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
+				USB_DEVICE_ID_UGEE_TABLET_EX07S) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
+				USB_DEVICE_ID_UGEE_XPPEN_TABLET_G540) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
+				USB_DEVICE_ID_UGEE_XPPEN_TABLET_G640) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
+				USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO01) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, uclogic_devices);
+
+static struct hid_driver uclogic_driver = {
+	.name = "uclogic",
+	.id_table = uclogic_devices,
+	.probe = uclogic_probe,
+	.remove = uclogic_remove,
+	.report_fixup = uclogic_report_fixup,
+	.raw_event = uclogic_raw_event,
+	.input_mapping = uclogic_input_mapping,
+	.input_configured = uclogic_input_configured,
+#ifdef CONFIG_PM
+	.resume	          = uclogic_resume,
+	.reset_resume     = uclogic_resume,
+#endif
+};
+module_hid_driver(uclogic_driver);
+
+MODULE_AUTHOR("Martin Rusko");
+MODULE_AUTHOR("Nikolai Kondrashov");
+MODULE_LICENSE("GPL");

drivers/hid/hid-uclogic-params.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  HID driver for UC-Logic devices not fully compliant with HID standard
+ *  - tablet initialization and parameter retrieval
+ *
+ *  Copyright (c) 2018 Nikolai Kondrashov
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include "hid-uclogic-params.h"
+#include "hid-uclogic-rdesc.h"
+#include "usbhid/usbhid.h"
+#include "hid-ids.h"
+#include <linux/ctype.h>
+#include <asm/unaligned.h>
+
+/**
+ * Convert a pen in-range reporting type to a string.
+ *
+ * @inrange:	The in-range reporting type to convert.
+ *
+ * Returns:
+ *	The string representing the type, or NULL if the type is unknown.
+ */
+const char *uclogic_params_pen_inrange_to_str(
+			enum uclogic_params_pen_inrange inrange)
+{
+	switch (inrange) {
+	case UCLOGIC_PARAMS_PEN_INRANGE_NORMAL:
+		return "normal";
+	case UCLOGIC_PARAMS_PEN_INRANGE_INVERTED:
+		return "inverted";
+	case UCLOGIC_PARAMS_PEN_INRANGE_NONE:
+		return "none";
+	default:
+		return NULL;
+	}
+}
+
+/**
+ * uclogic_params_get_str_desc - retrieve a string descriptor from a HID
+ * device interface, putting it into a kmalloc-allocated buffer as is, without
+ * character encoding conversion.
+ *
+ * @pbuf:	Location for the kmalloc-allocated buffer pointer containing
+ *		the retrieved descriptor. Not modified in case of error.
+ *		Can be NULL to have retrieved descriptor discarded.
+ * @hdev:	The HID device of the tablet interface to retrieve the string
+ *		descriptor from. Cannot be NULL.
+ * @idx:	Index of the string descriptor to request from the device.
+ * @len:	Length of the buffer to allocate and the data to retrieve.
+ *
+ * Returns:
+ *	number of bytes retrieved (<= len),
+ *	-EPIPE, if the descriptor was not found, or
+ *	another negative errno code in case of other error.
+ */
+static int uclogic_params_get_str_desc(__u8 **pbuf, struct hid_device *hdev,
+					__u8 idx, size_t len)
+{
+	int rc;
+	struct usb_device *udev = hid_to_usb_dev(hdev);
+	__u8 *buf = NULL;
+
+	/* Check arguments */
+	if (hdev == NULL) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	buf = kmalloc(len, GFP_KERNEL);
+	if (buf == NULL) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+
+	rc = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
+				USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
+				(USB_DT_STRING << 8) + idx,
+				0x0409, buf, len,
+				USB_CTRL_GET_TIMEOUT);
+	if (rc == -EPIPE) {
+		hid_dbg(hdev, "string descriptor #%hhu not found\n", idx);
+		goto cleanup;
+	} else if (rc < 0) {
+		hid_err(hdev,
+			"failed retrieving string descriptor #%hhu: %d\n",
+			idx, rc);
+		goto cleanup;
+	}
+
+	if (pbuf != NULL) {
+		*pbuf = buf;
+		buf = NULL;
+	}
+
+cleanup:
+	kfree(buf);
+	return rc;
+}
+
+/**
+ * uclogic_params_pen_cleanup - free resources used by struct
+ * uclogic_params_pen (tablet interface's pen input parameters).
+ * Can be called repeatedly.
+ *
+ * @pen:	Pen input parameters to cleanup. Cannot be NULL.
+ */
+static void uclogic_params_pen_cleanup(struct uclogic_params_pen *pen)
+{
+	kfree(pen->desc_ptr);
+	memset(pen, 0, sizeof(*pen));
+}
+
+/**
+ * uclogic_params_pen_init_v1() - initialize tablet interface pen
+ * input and retrieve its parameters from the device, using v1 protocol.
+ *
+ * @pen:	Pointer to the pen parameters to initialize (to be
+ *		cleaned up with uclogic_params_pen_cleanup()). Not modified in
+ *		case of error, or if parameters are not found. Cannot be NULL.
+ * @pfound:	Location for a flag which is set to true if the parameters
+ *		were found, and to false if not (e.g. device was
+ *		incompatible). Not modified in case of error. Cannot be NULL.
+ * @hdev:	The HID device of the tablet interface to initialize and get
+ *		parameters from. Cannot be NULL.
+ *
+ * Returns:
+ *	Zero, if successful. A negative errno code on error.
+ */
+static int uclogic_params_pen_init_v1(struct uclogic_params_pen *pen,
+				      bool *pfound,
+				      struct hid_device *hdev)
+{
+	int rc;
+	bool found = false;
+	/* Buffer for (part of) the string descriptor */
+	__u8 *buf = NULL;
+	/* Minimum descriptor length required, maximum seen so far is 18 */
+	const int len = 12;
+	s32 resolution;
+	/* Pen report descriptor template parameters */
+	s32 desc_params[UCLOGIC_RDESC_PEN_PH_ID_NUM];
+	__u8 *desc_ptr = NULL;
+
+	/* Check arguments */
+	if (pen == NULL || pfound == NULL || hdev == NULL) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	/*
+	 * Read string descriptor containing pen input parameters.
+	 * The specific string descriptor and data were discovered by sniffing
+	 * the Windows driver traffic.
+	 * NOTE: This enables fully-functional tablet mode.
+	 */
+	rc = uclogic_params_get_str_desc(&buf, hdev, 100, len);
+	if (rc == -EPIPE) {
+		hid_dbg(hdev,
+			"string descriptor with pen parameters not found, assuming not compatible\n");
+		goto finish;
+	} else if (rc < 0) {
+		hid_err(hdev, "failed retrieving pen parameters: %d\n", rc);
+		goto cleanup;
+	} else if (rc != len) {
+		hid_dbg(hdev,
+			"string descriptor with pen parameters has invalid length (got %d, expected %d), assuming not compatible\n",
+			rc, len);
+		goto finish;
+	}
+
+	/*
+	 * Fill report descriptor parameters from the string descriptor
+	 */
+	desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] =
+		get_unaligned_le16(buf + 2);
+	desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] =
+		get_unaligned_le16(buf + 4);
+	desc_params[UCLOGIC_RDESC_PEN_PH_ID_PRESSURE_LM] =
+		get_unaligned_le16(buf + 8);
+	resolution = get_unaligned_le16(buf + 10);
+	if (resolution == 0) {
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] = 0;
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] = 0;
+	} else {
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] =
+			desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] * 1000 /
+			resolution;
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] =
+			desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] * 1000 /
+			resolution;
+	}
+	kfree(buf);
+	buf = NULL;
+
+	/*
+	 * Generate pen report descriptor
+	 */
+	desc_ptr = uclogic_rdesc_template_apply(
+				uclogic_rdesc_pen_v1_template_arr,
+				uclogic_rdesc_pen_v1_template_size,
+				desc_params, ARRAY_SIZE(desc_params));
+	if (desc_ptr == NULL) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+
+	/*
+	 * Fill-in the parameters
+	 */
+	memset(pen, 0, sizeof(*pen));
+	pen->desc_ptr = desc_ptr;
+	desc_ptr = NULL;
+	pen->desc_size = uclogic_rdesc_pen_v1_template_size;
+	pen->id = UCLOGIC_RDESC_PEN_V1_ID;
+	pen->inrange = UCLOGIC_PARAMS_PEN_INRANGE_INVERTED;
+	found = true;
+finish:
+	*pfound = found;
+	rc = 0;
+cleanup:
+	kfree(desc_ptr);
+	kfree(buf);
+	return rc;
+}
+
+/**
+ * uclogic_params_get_le24() - get a 24-bit little-endian number from a
+ * buffer.
+ *
+ * @p:	The pointer to the number buffer.
+ *
+ * Returns:
+ *	The retrieved number
+ */
+static s32 uclogic_params_get_le24(const void *p)
+{
+	const __u8 *b = p;
+	return b[0] | (b[1] << 8UL) | (b[2] << 16UL);
+}
+
+/**
+ * uclogic_params_pen_init_v2() - initialize tablet interface pen
+ * input and retrieve its parameters from the device, using v2 protocol.
+ *
+ * @pen:	Pointer to the pen parameters to initialize (to be
+ *		cleaned up with uclogic_params_pen_cleanup()). Not modified in
+ *		case of error, or if parameters are not found. Cannot be NULL.
+ * @pfound:	Location for a flag which is set to true if the parameters
+ *		were found, and to false if not (e.g. device was
+ *		incompatible). Not modified in case of error. Cannot be NULL.
+ * @hdev:	The HID device of the tablet interface to initialize and get
+ *		parameters from. Cannot be NULL.
+ *
+ * Returns:
+ *	Zero, if successful. A negative errno code on error.
+ */
+static int uclogic_params_pen_init_v2(struct uclogic_params_pen *pen,
+					bool *pfound,
+					struct hid_device *hdev)
+{
+	int rc;
+	bool found = false;
+	/* Buffer for (part of) the string descriptor */
+	__u8 *buf = NULL;
+	/* Descriptor length required */
+	const int len = 18;
+	s32 resolution;
+	/* Pen report descriptor template parameters */
+	s32 desc_params[UCLOGIC_RDESC_PEN_PH_ID_NUM];
+	__u8 *desc_ptr = NULL;
+
+	/* Check arguments */
+	if (pen == NULL || pfound == NULL || hdev == NULL) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	/*
+	 * Read string descriptor containing pen input parameters.
+	 * The specific string descriptor and data were discovered by sniffing
+	 * the Windows driver traffic.
+	 * NOTE: This enables fully-functional tablet mode.
+	 */
+	rc = uclogic_params_get_str_desc(&buf, hdev, 200, len);
+	if (rc == -EPIPE) {
+		hid_dbg(hdev,
+			"string descriptor with pen parameters not found, assuming not compatible\n");
+		goto finish;
+	} else if (rc < 0) {
+		hid_err(hdev, "failed retrieving pen parameters: %d\n", rc);
+		goto cleanup;
+	} else if (rc != len) {
+		hid_dbg(hdev,
+			"string descriptor with pen parameters has invalid length (got %d, expected %d), assuming not compatible\n",
+			rc, len);
+		goto finish;
+	} else {
+		size_t i;
+		/*
+		 * Check it's not just a catch-all UTF-16LE-encoded ASCII
+		 * string (such as the model name) some tablets put into all
+		 * unknown string descriptors.
+		 */
+		for (i = 2;
+		     i < len &&
+			(buf[i] >= 0x20 && buf[i] < 0x7f && buf[i + 1] == 0);
+		     i += 2);
+		if (i >= len) {
+			hid_dbg(hdev,
+				"string descriptor with pen parameters seems to contain only text, assuming not compatible\n");
+			goto finish;
+		}
+	}
+
+	/*
+	 * Fill report descriptor parameters from the string descriptor
+	 */
+	desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] =
+		uclogic_params_get_le24(buf + 2);
+	desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] =
+		uclogic_params_get_le24(buf + 5);
+	desc_params[UCLOGIC_RDESC_PEN_PH_ID_PRESSURE_LM] =
+		get_unaligned_le16(buf + 8);
+	resolution = get_unaligned_le16(buf + 10);
+	if (resolution == 0) {
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] = 0;
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] = 0;
+	} else {
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] =
+			desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] * 1000 /
+			resolution;
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] =
+			desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] * 1000 /
+			resolution;
+	}
+	kfree(buf);
+	buf = NULL;
+
+	/*
+	 * Generate pen report descriptor
+	 */
+	desc_ptr = uclogic_rdesc_template_apply(
+				uclogic_rdesc_pen_v2_template_arr,
+				uclogic_rdesc_pen_v2_template_size,
+				desc_params, ARRAY_SIZE(desc_params));
+	if (desc_ptr == NULL) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+
+	/*
+	 * Fill-in the parameters
+	 */
+	memset(pen, 0, sizeof(*pen));
+	pen->desc_ptr = desc_ptr;
+	desc_ptr = NULL;
+	pen->desc_size = uclogic_rdesc_pen_v2_template_size;
+	pen->id = UCLOGIC_RDESC_PEN_V2_ID;
+	pen->inrange = UCLOGIC_PARAMS_PEN_INRANGE_NONE;
+	pen->fragmented_hires = true;
+	found = true;
+finish:
+	*pfound = found;
+	rc = 0;
+cleanup:
+	kfree(desc_ptr);
+	kfree(buf);
+	return rc;
+}
+
+/**
+ * uclogic_params_frame_cleanup - free resources used by struct
+ * uclogic_params_frame (tablet interface's frame controls input parameters).
+ * Can be called repeatedly.
+ *
+ * @frame:	Frame controls input parameters to cleanup. Cannot be NULL.
+ */
+static void uclogic_params_frame_cleanup(struct uclogic_params_frame *frame)
+{
+	kfree(frame->desc_ptr);
+	memset(frame, 0, sizeof(*frame));
+}
+
+/**
+ * uclogic_params_frame_init_with_desc() - initialize tablet's frame control
+ * parameters with a static report descriptor.
+ *
+ * @frame:	Pointer to the frame parameters to initialize (to be cleaned
+ *		up with uclogic_params_frame_cleanup()). Not modified in case
+ *		of error. Cannot be NULL.
+ * @desc_ptr:	Report descriptor pointer. Can be NULL, if desc_size is zero.
+ * @desc_size:	Report descriptor size.
+ * @id:		Report ID used for frame reports, if they should be tweaked,
+ *		zero if not.
+ *
+ * Returns:
+ *	Zero, if successful. A negative errno code on error.
+ */
+static int uclogic_params_frame_init_with_desc(
+					struct uclogic_params_frame *frame,
+					const __u8 *desc_ptr,
+					size_t desc_size,
+					unsigned int id)
+{
+	__u8 *copy_desc_ptr;
+
+	if (frame == NULL || (desc_ptr == NULL && desc_size != 0))
+		return -EINVAL;
+
+	copy_desc_ptr = kmemdup(desc_ptr, desc_size, GFP_KERNEL);
+	if (copy_desc_ptr == NULL)
+		return -ENOMEM;
+
+	memset(frame, 0, sizeof(*frame));
+	frame->desc_ptr = copy_desc_ptr;
+	frame->desc_size = desc_size;
+	frame->id = id;
+	return 0;
+}
+
+/**
+ * uclogic_params_frame_init_v1_buttonpad() - initialize abstract buttonpad
+ * on a v1 tablet interface.
+ *
+ * @frame:	Pointer to the frame parameters to initialize (to be cleaned
+ *		up with uclogic_params_frame_cleanup()). Not modified in case
+ *		of error, or if parameters are not found. Cannot be NULL.
+ * @pfound:	Location for a flag which is set to true if the parameters
+ *		were found, and to false if not (e.g. device was
+ *		incompatible). Not modified in case of error. Cannot be NULL.
+ * @hdev:	The HID device of the tablet interface to initialize and get
+ *		parameters from. Cannot be NULL.
+ *
+ * Returns:
+ *	Zero, if successful. A negative errno code on error.
+ */
+static int uclogic_params_frame_init_v1_buttonpad(
+					struct uclogic_params_frame *frame,
+					bool *pfound,
+					struct hid_device *hdev)
+{
+	int rc;
+	bool found = false;
+	struct usb_device *usb_dev = hid_to_usb_dev(hdev);
+	char *str_buf = NULL;
+	const size_t str_len = 16;
+
+	/* Check arguments */
+	if (frame == NULL || pfound == NULL || hdev == NULL) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	/*
+	 * Enable generic button mode
+	 */
+	str_buf = kzalloc(str_len, GFP_KERNEL);
+	if (str_buf == NULL) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+
+	rc = usb_string(usb_dev, 123, str_buf, str_len);
+	if (rc == -EPIPE) {
+		hid_dbg(hdev,
+			"generic button -enabling string descriptor not found\n");
+	} else if (rc < 0) {
+		goto cleanup;
+	} else if (strncmp(str_buf, "HK On", rc) != 0) {
+		hid_dbg(hdev,
+			"invalid response to enabling generic buttons: \"%s\"\n",
+			str_buf);
+	} else {
+		hid_dbg(hdev, "generic buttons enabled\n");
+		rc = uclogic_params_frame_init_with_desc(
+				frame,
+				uclogic_rdesc_buttonpad_v1_arr,
+				uclogic_rdesc_buttonpad_v1_size,
+				UCLOGIC_RDESC_BUTTONPAD_V1_ID);
+		if (rc != 0)
+			goto cleanup;
+		found = true;
+	}
+
+	*pfound = found;
+	rc = 0;
+cleanup:
+	kfree(str_buf);
+	return rc;
+}
+
+/**
+ * uclogic_params_cleanup - free resources used by struct uclogic_params
+ * (tablet interface's parameters).
+ * Can be called repeatedly.
+ *
+ * @params:	Input parameters to cleanup. Cannot be NULL.
+ */
+void uclogic_params_cleanup(struct uclogic_params *params)
+{
+	if (!params->invalid) {
+		kfree(params->desc_ptr);
+		if (!params->pen_unused)
+			uclogic_params_pen_cleanup(&params->pen);
+		uclogic_params_frame_cleanup(&params->frame);
+		memset(params, 0, sizeof(*params));
+	}
+}
+
+/**
+ * Get a replacement report descriptor for a tablet's interface.
+ *
+ * @params:	The parameters of a tablet interface to get report
+ *		descriptor for. Cannot be NULL.
+ * @pdesc:	Location for the resulting, kmalloc-allocated report
+ *		descriptor pointer, or for NULL, if there's no replacement
+ *		report descriptor. Not modified in case of error. Cannot be
+ *		NULL.
+ * @psize:	Location for the resulting report descriptor size, not set if
+ *		there's no replacement report descriptor. Not modified in case
+ *		of error. Cannot be NULL.
+ *
+ * Returns:
+ *	Zero, if successful.
+ *	-EINVAL, if invalid arguments are supplied.
+ *	-ENOMEM, if failed to allocate memory.
+ */
+int uclogic_params_get_desc(const struct uclogic_params *params,
+				__u8 **pdesc,
+				unsigned int *psize)
+{
+	bool common_present;
+	bool pen_present;
+	bool frame_present;
+	unsigned int size;
+	__u8 *desc = NULL;
+
+	/* Check arguments */
+	if (params == NULL || pdesc == NULL || psize == NULL)
+		return -EINVAL;
+
+	size = 0;
+
+	common_present = (params->desc_ptr != NULL);
+	pen_present = (!params->pen_unused && params->pen.desc_ptr != NULL);
+	frame_present = (params->frame.desc_ptr != NULL);
+
+	if (common_present)
+		size += params->desc_size;
+	if (pen_present)
+		size += params->pen.desc_size;
+	if (frame_present)
+		size += params->frame.desc_size;
+
+	if (common_present || pen_present || frame_present) {
+		__u8 *p;
+
+		desc = kmalloc(size, GFP_KERNEL);
+		if (desc == NULL)
+			return -ENOMEM;
+		p = desc;
+
+		if (common_present) {
+			memcpy(p, params->desc_ptr,
+				params->desc_size);
+			p += params->desc_size;
+		}
+		if (pen_present) {
+			memcpy(p, params->pen.desc_ptr,
+				params->pen.desc_size);
+			p += params->pen.desc_size;
+		}
+		if (frame_present) {
+			memcpy(p, params->frame.desc_ptr,
+				params->frame.desc_size);
+			p += params->frame.desc_size;
+		}
+
+		WARN_ON(p != desc + size);
+
+		*psize = size;
+	}
+
+	*pdesc = desc;
+	return 0;
+}
+
+/**
+ * uclogic_params_init_invalid() - initialize tablet interface parameters,
+ * specifying the interface is invalid.
+ *
+ * @params:		Parameters to initialize (to be cleaned with
+ *			uclogic_params_cleanup()). Cannot be NULL.
+ */
+static void uclogic_params_init_invalid(struct uclogic_params *params)
+{
+	params->invalid = true;
+}
+
+/**
+ * uclogic_params_init_with_opt_desc() - initialize tablet interface
+ * parameters with an optional replacement report descriptor. Only modify
+ * report descriptor, if the original report descriptor matches the expected
+ * size.
+ *
+ * @params:		Parameters to initialize (to be cleaned with
+ *			uclogic_params_cleanup()). Not modified in case of
+ *			error. Cannot be NULL.
+ * @hdev:		The HID device of the tablet interface create the
+ *			parameters for. Cannot be NULL.
+ * @orig_desc_size:	Expected size of the original report descriptor to
+ *			be replaced.
+ * @desc_ptr:		Pointer to the replacement report descriptor.
+ *			Can be NULL, if desc_size is zero.
+ * @desc_size:		Size of the replacement report descriptor.
+ *
+ * Returns:
+ *	Zero, if successful. -EINVAL if an invalid argument was passed.
+ *	-ENOMEM, if failed to allocate memory.
+ */
+static int uclogic_params_init_with_opt_desc(struct uclogic_params *params,
+					     struct hid_device *hdev,
+					     unsigned int orig_desc_size,
+					     __u8 *desc_ptr,
+					     unsigned int desc_size)
+{
+	__u8 *desc_copy_ptr = NULL;
+	unsigned int desc_copy_size;
+	int rc;
+
+	/* Check arguments */
+	if (params == NULL || hdev == NULL ||
+	    (desc_ptr == NULL && desc_size != 0)) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	/* Replace report descriptor, if it matches */
+	if (hdev->dev_rsize == orig_desc_size) {
+		hid_dbg(hdev,
+			"device report descriptor matches the expected size, replacing\n");
+		desc_copy_ptr = kmemdup(desc_ptr, desc_size, GFP_KERNEL);
+		if (desc_copy_ptr == NULL) {
+			rc = -ENOMEM;
+			goto cleanup;
+		}
+		desc_copy_size = desc_size;
+	} else {
+		hid_dbg(hdev,
+			"device report descriptor doesn't match the expected size (%u != %u), preserving\n",
+			hdev->dev_rsize, orig_desc_size);
+		desc_copy_ptr = NULL;
+		desc_copy_size = 0;
+	}
+
+	/* Output parameters */
+	memset(params, 0, sizeof(*params));
+	params->desc_ptr = desc_copy_ptr;
+	desc_copy_ptr = NULL;
+	params->desc_size = desc_copy_size;
+
+	rc = 0;
+cleanup:
+	kfree(desc_copy_ptr);
+	return rc;
+}
+
+/**
+ * uclogic_params_init_with_pen_unused() - initialize tablet interface
+ * parameters preserving original reports and generic HID processing, but
+ * disabling pen usage.
+ *
+ * @params:		Parameters to initialize (to be cleaned with
+ *			uclogic_params_cleanup()). Not modified in case of
+ *			error. Cannot be NULL.
+ */
+static void uclogic_params_init_with_pen_unused(struct uclogic_params *params)
+{
+	memset(params, 0, sizeof(*params));
+	params->pen_unused = true;
+}
+
+/**
+ * uclogic_params_init() - initialize a Huion tablet interface and discover
+ * its parameters.
+ *
+ * @params:	Parameters to fill in (to be cleaned with
+ *		uclogic_params_cleanup()). Not modified in case of error.
+ *		Cannot be NULL.
+ * @hdev:	The HID device of the tablet interface to initialize and get
+ *		parameters from. Cannot be NULL.
+ *
+ * Returns:
+ *	Zero, if successful. A negative errno code on error.
+ */
+static int uclogic_params_huion_init(struct uclogic_params *params,
+				     struct hid_device *hdev)
+{
+	int rc;
+	struct usb_device *udev = hid_to_usb_dev(hdev);
+	struct usb_interface *iface = to_usb_interface(hdev->dev.parent);
+	__u8 bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber;
+	bool found;
+	/* The resulting parameters (noop) */
+	struct uclogic_params p = {0, };
+	static const char transition_ver[] = "HUION_T153_160607";
+	char *ver_ptr = NULL;
+	const size_t ver_len = sizeof(transition_ver) + 1;
+
+	/* Check arguments */
+	if (params == NULL || hdev == NULL) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	/* If it's not a pen interface */
+	if (bInterfaceNumber != 0) {
+		/* TODO: Consider marking the interface invalid */
+		uclogic_params_init_with_pen_unused(&p);
+		goto output;
+	}
+
+	/* Try to get firmware version */
+	ver_ptr = kzalloc(ver_len, GFP_KERNEL);
+	if (ver_ptr == NULL) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+	rc = usb_string(udev, 201, ver_ptr, ver_len);
+	if (ver_ptr == NULL) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+	if (rc == -EPIPE) {
+		*ver_ptr = '\0';
+	} else if (rc < 0) {
+		hid_err(hdev,
+			"failed retrieving Huion firmware version: %d\n", rc);
+		goto cleanup;
+	}
+
+	/* If this is a transition firmware */
+	if (strcmp(ver_ptr, transition_ver) == 0) {
+		hid_dbg(hdev,
+			"transition firmware detected, not probing pen v2 parameters\n");
+	} else {
+		/* Try to probe v2 pen parameters */
+		rc = uclogic_params_pen_init_v2(&p.pen, &found, hdev);
+		if (rc != 0) {
+			hid_err(hdev,
+				"failed probing pen v2 parameters: %d\n", rc);
+			goto cleanup;
+		} else if (found) {
+			hid_dbg(hdev, "pen v2 parameters found\n");
+			/* Create v2 buttonpad parameters */
+			rc = uclogic_params_frame_init_with_desc(
+					&p.frame,
+					uclogic_rdesc_buttonpad_v2_arr,
+					uclogic_rdesc_buttonpad_v2_size,
+					UCLOGIC_RDESC_BUTTONPAD_V2_ID);
+			if (rc != 0) {
+				hid_err(hdev,
+					"failed creating v2 buttonpad parameters: %d\n",
+					rc);
+				goto cleanup;
+			}
+			/* Set bitmask marking frame reports in pen reports */
+			p.pen_frame_flag = 0x20;
+			goto output;
+		}
+		hid_dbg(hdev, "pen v2 parameters not found\n");
+	}
+
+	/* Try to probe v1 pen parameters */
+	rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
+	if (rc != 0) {
+		hid_err(hdev,
+			"failed probing pen v1 parameters: %d\n", rc);
+		goto cleanup;
+	} else if (found) {
+		hid_dbg(hdev, "pen v1 parameters found\n");
+		/* Try to probe v1 buttonpad */
+		rc = uclogic_params_frame_init_v1_buttonpad(
+						&p.frame,
+						&found, hdev);
+		if (rc != 0) {
+			hid_err(hdev, "v1 buttonpad probing failed: %d\n", rc);
+			goto cleanup;
+		}
+		hid_dbg(hdev, "buttonpad v1 parameters%s found\n",
+			(found ? "" : " not"));
+		if (found) {
+			/* Set bitmask marking frame reports */
+			p.pen_frame_flag = 0x20;
+		}
+		goto output;
+	}
+	hid_dbg(hdev, "pen v1 parameters not found\n");
+
+	uclogic_params_init_invalid(&p);
+
+output:
+	/* Output parameters */
+	memcpy(params, &p, sizeof(*params));
+	memset(&p, 0, sizeof(p));
+	rc = 0;
+cleanup:
+	kfree(ver_ptr);
+	uclogic_params_cleanup(&p);
+	return rc;
+}
+
+/**
+ * uclogic_params_init() - initialize a tablet interface and discover its
+ * parameters.
+ *
+ * @params:	Parameters to fill in (to be cleaned with
+ *		uclogic_params_cleanup()). Not modified in case of error.
+ *		Cannot be NULL.
+ * @hdev:	The HID device of the tablet interface to initialize and get
+ *		parameters from. Cannot be NULL. Must be using the USB low-level
+ *		driver, i.e. be an actual USB tablet.
+ *
+ * Returns:
+ *	Zero, if successful. A negative errno code on error.
+ */
+int uclogic_params_init(struct uclogic_params *params,
+			struct hid_device *hdev)
+{
+	int rc;
+	struct usb_device *udev = hid_to_usb_dev(hdev);
+	__u8  bNumInterfaces = udev->config->desc.bNumInterfaces;
+	struct usb_interface *iface = to_usb_interface(hdev->dev.parent);
+	__u8 bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber;
+	bool found;
+	/* The resulting parameters (noop) */
+	struct uclogic_params p = {0, };
+
+	/* Check arguments */
+	if (params == NULL || hdev == NULL ||
+	    !hid_is_using_ll_driver(hdev, &usb_hid_driver)) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	/*
+	 * Set replacement report descriptor if the original matches the
+	 * specified size. Otherwise keep interface unchanged.
+	 */
+#define WITH_OPT_DESC(_orig_desc_token, _new_desc_token) \
+	uclogic_params_init_with_opt_desc(                  \
+		&p, hdev,                                   \
+		UCLOGIC_RDESC_##_orig_desc_token##_SIZE,    \
+		uclogic_rdesc_##_new_desc_token##_arr,      \
+		uclogic_rdesc_##_new_desc_token##_size)
+
+#define VID_PID(_vid, _pid) \
+	(((__u32)(_vid) << 16) | ((__u32)(_pid) & U16_MAX))
+
+	/*
+	 * Handle specific interfaces for specific tablets.
+	 *
+	 * Observe the following logic:
+	 *
+	 * If the interface is recognized as producing certain useful input:
+	 *	Mark interface as valid.
+	 *	Output interface parameters.
+	 * Else, if the interface is recognized as *not* producing any useful
+	 * input:
+	 *	Mark interface as invalid.
+	 * Else:
+	 *	Mark interface as valid.
+	 *	Output noop parameters.
+	 *
+	 * Rule of thumb: it is better to disable a broken interface than let
+	 *		  it spew garbage input.
+	 */
+
+	switch (VID_PID(hdev->vendor, hdev->product)) {
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_TABLET_PF1209):
+		rc = WITH_OPT_DESC(PF1209_ORIG, pf1209_fixed);
+		if (rc != 0)
+			goto cleanup;
+		break;
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_TABLET_WP4030U):
+		rc = WITH_OPT_DESC(WPXXXXU_ORIG, wp4030u_fixed);
+		if (rc != 0)
+			goto cleanup;
+		break;
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_TABLET_WP5540U):
+		if (hdev->dev_rsize == UCLOGIC_RDESC_WP5540U_V2_ORIG_SIZE) {
+			if (bInterfaceNumber == 0) {
+				/* Try to probe v1 pen parameters */
+				rc = uclogic_params_pen_init_v1(&p.pen,
+								&found, hdev);
+				if (rc != 0) {
+					hid_err(hdev,
+						"pen probing failed: %d\n",
+						rc);
+					goto cleanup;
+				}
+				if (!found) {
+					hid_warn(hdev,
+						 "pen parameters not found");
+				}
+			} else {
+				uclogic_params_init_invalid(&p);
+			}
+		} else {
+			rc = WITH_OPT_DESC(WPXXXXU_ORIG, wp5540u_fixed);
+			if (rc != 0)
+				goto cleanup;
+		}
+		break;
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_TABLET_WP8060U):
+		rc = WITH_OPT_DESC(WPXXXXU_ORIG, wp8060u_fixed);
+		if (rc != 0)
+			goto cleanup;
+		break;
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_TABLET_WP1062):
+		rc = WITH_OPT_DESC(WP1062_ORIG, wp1062_fixed);
+		if (rc != 0)
+			goto cleanup;
+		break;
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_WIRELESS_TABLET_TWHL850):
+		switch (bInterfaceNumber) {
+		case 0:
+			rc = WITH_OPT_DESC(TWHL850_ORIG0, twhl850_fixed0);
+			if (rc != 0)
+				goto cleanup;
+			break;
+		case 1:
+			rc = WITH_OPT_DESC(TWHL850_ORIG1, twhl850_fixed1);
+			if (rc != 0)
+				goto cleanup;
+			break;
+		case 2:
+			rc = WITH_OPT_DESC(TWHL850_ORIG2, twhl850_fixed2);
+			if (rc != 0)
+				goto cleanup;
+			break;
+		}
+		break;
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_TABLET_TWHA60):
+		/*
+		 * If it is not a three-interface version, which is known to
+		 * respond to initialization.
+		 */
+		if (bNumInterfaces != 3) {
+			switch (bInterfaceNumber) {
+			case 0:
+				rc = WITH_OPT_DESC(TWHA60_ORIG0,
+							twha60_fixed0);
+				if (rc != 0)
+					goto cleanup;
+				break;
+			case 1:
+				rc = WITH_OPT_DESC(TWHA60_ORIG1,
+							twha60_fixed1);
+				if (rc != 0)
+					goto cleanup;
+				break;
+			}
+			break;
+		}
+		/* FALL THROUGH */
+	case VID_PID(USB_VENDOR_ID_HUION,
+		     USB_DEVICE_ID_HUION_TABLET):
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_HUION_TABLET):
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_YIYNOVA_TABLET):
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_81):
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_DRAWIMAGE_G3):
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_45):
+	case VID_PID(USB_VENDOR_ID_UCLOGIC,
+		     USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_47):
+		rc = uclogic_params_huion_init(&p, hdev);
+		if (rc != 0)
+			goto cleanup;
+		break;
+	case VID_PID(USB_VENDOR_ID_UGTIZER,
+		     USB_DEVICE_ID_UGTIZER_TABLET_GP0610):
+	case VID_PID(USB_VENDOR_ID_UGEE,
+		     USB_DEVICE_ID_UGEE_XPPEN_TABLET_G540):
+	case VID_PID(USB_VENDOR_ID_UGEE,
+		     USB_DEVICE_ID_UGEE_XPPEN_TABLET_G640):
+		/* If this is the pen interface */
+		if (bInterfaceNumber == 1) {
+			/* Probe v1 pen parameters */
+			rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
+			if (rc != 0) {
+				hid_err(hdev, "pen probing failed: %d\n", rc);
+				goto cleanup;
+			}
+			if (!found) {
+				hid_warn(hdev, "pen parameters not found");
+				uclogic_params_init_invalid(&p);
+			}
+		} else {
+			/* TODO: Consider marking the interface invalid */
+			uclogic_params_init_with_pen_unused(&p);
+		}
+		break;
+	case VID_PID(USB_VENDOR_ID_UGEE,
+		     USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO01):
+		/* If this is the pen and frame interface */
+		if (bInterfaceNumber == 1) {
+			/* Probe v1 pen parameters */
+			rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
+			if (rc != 0) {
+				hid_err(hdev, "pen probing failed: %d\n", rc);
+				goto cleanup;
+			}
+			/* Initialize frame parameters */
+			rc = uclogic_params_frame_init_with_desc(
+				&p.frame,
+				uclogic_rdesc_xppen_deco01_frame_arr,
+				uclogic_rdesc_xppen_deco01_frame_size,
+				0);
+			if (rc != 0)
+				goto cleanup;
+		} else {
+			/* TODO: Consider marking the interface invalid */
+			uclogic_params_init_with_pen_unused(&p);
+		}
+		break;
+	case VID_PID(USB_VENDOR_ID_UGEE,
+		     USB_DEVICE_ID_UGEE_TABLET_G5):
+		/* Ignore non-pen interfaces */
+		if (bInterfaceNumber != 1) {
+			uclogic_params_init_invalid(&p);
+			break;
+		}
+
+		rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
+		if (rc != 0) {
+			hid_err(hdev, "pen probing failed: %d\n", rc);
+			goto cleanup;
+		} else if (found) {
+			rc = uclogic_params_frame_init_with_desc(
+				&p.frame,
+				uclogic_rdesc_ugee_g5_frame_arr,
+				uclogic_rdesc_ugee_g5_frame_size,
+				UCLOGIC_RDESC_UGEE_G5_FRAME_ID);
+			if (rc != 0) {
+				hid_err(hdev,
+					"failed creating buttonpad parameters: %d\n",
+					rc);
+				goto cleanup;
+			}
+			p.frame.re_lsb =
+				UCLOGIC_RDESC_UGEE_G5_FRAME_RE_LSB;
+			p.frame.dev_id_byte =
+				UCLOGIC_RDESC_UGEE_G5_FRAME_DEV_ID_BYTE;
+		} else {
+			hid_warn(hdev, "pen parameters not found");
+			uclogic_params_init_invalid(&p);
+		}
+
+		break;
+	case VID_PID(USB_VENDOR_ID_UGEE,
+		     USB_DEVICE_ID_UGEE_TABLET_EX07S):
+		/* Ignore non-pen interfaces */
+		if (bInterfaceNumber != 1) {
+			uclogic_params_init_invalid(&p);
+			break;
+		}
+
+		rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
+		if (rc != 0) {
+			hid_err(hdev, "pen probing failed: %d\n", rc);
+			goto cleanup;
+		} else if (found) {
+			rc = uclogic_params_frame_init_with_desc(
+				&p.frame,
+				uclogic_rdesc_ugee_ex07_buttonpad_arr,
+				uclogic_rdesc_ugee_ex07_buttonpad_size,
+				0);
+			if (rc != 0) {
+				hid_err(hdev,
+					"failed creating buttonpad parameters: %d\n",
+					rc);
+				goto cleanup;
+			}
+		} else {
+			hid_warn(hdev, "pen parameters not found");
+			uclogic_params_init_invalid(&p);
+		}
+
+		break;
+	}
+
+#undef VID_PID
+#undef WITH_OPT_DESC
+
+	/* Output parameters */
+	memcpy(params, &p, sizeof(*params));
+	memset(&p, 0, sizeof(p));
+	rc = 0;
+cleanup:
+	uclogic_params_cleanup(&p);
+	return rc;
+}

drivers/hid/hid-uclogic-params.h

+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ *  HID driver for UC-Logic devices not fully compliant with HID standard
+ *  - tablet initialization and parameter retrieval
+ *
+ *  Copyright (c) 2018 Nikolai Kondrashov
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#ifndef _HID_UCLOGIC_PARAMS_H
+#define _HID_UCLOGIC_PARAMS_H
+
+#include <linux/usb.h>
+#include <linux/hid.h>
+
+/* Types of pen in-range reporting */
+enum uclogic_params_pen_inrange {
+	/* Normal reports: zero - out of proximity, one - in proximity */
+	UCLOGIC_PARAMS_PEN_INRANGE_NORMAL = 0,
+	/* Inverted reports: zero - in proximity, one - out of proximity */
+	UCLOGIC_PARAMS_PEN_INRANGE_INVERTED,
+	/* No reports */
+	UCLOGIC_PARAMS_PEN_INRANGE_NONE,
+};
+
+/* Convert a pen in-range reporting type to a string */
+extern const char *uclogic_params_pen_inrange_to_str(
+			enum uclogic_params_pen_inrange inrange);
+
+/*
+ * Tablet interface's pen input parameters.
+ *
+ * Must use declarative (descriptive) language, not imperative, to simplify
+ * understanding and maintain consistency.
+ *
+ * Noop (preserving functionality) when filled with zeroes.
+ */
+struct uclogic_params_pen {
+	/*
+	 * Pointer to report descriptor describing the inputs.
+	 * Allocated with kmalloc.
+	 */
+	__u8 *desc_ptr;
+	/*
+	 * Size of the report descriptor.
+	 * Only valid, if "desc_ptr" is not NULL.
+	 */
+	unsigned int desc_size;
+	/* Report ID, if reports should be tweaked, zero if not */
+	unsigned int id;
+	/* Type of in-range reporting, only valid if "id" is not zero */
+	enum uclogic_params_pen_inrange inrange;
+	/*
+	 * True, if reports include fragmented high resolution coords, with
+	 * high-order X and then Y bytes following the pressure field.
+	 * Only valid if "id" is not zero.
+	 */
+	bool fragmented_hires;
+};
+
+/*
+ * Parameters of frame control inputs of a tablet interface.
+ *
+ * Must use declarative (descriptive) language, not imperative, to simplify
+ * understanding and maintain consistency.
+ *
+ * Noop (preserving functionality) when filled with zeroes.
+ */
+struct uclogic_params_frame {
+	/*
+	 * Pointer to report descriptor describing the inputs.
+	 * Allocated with kmalloc.
+	 */
+	__u8 *desc_ptr;
+	/*
+	 * Size of the report descriptor.
+	 * Only valid, if "desc_ptr" is not NULL.
+	 */
+	unsigned int desc_size;
+	/*
+	 * Report ID, if reports should be tweaked, zero if not.
+	 */
+	unsigned int id;
+	/*
+	 * Number of the least-significant bit of the 2-bit state of a rotary
+	 * encoder, in the report. Cannot point to a 2-bit field crossing a
+	 * byte boundary. Zero if not present. Only valid if "id" is not zero.
+	 */
+	unsigned int re_lsb;
+	/*
+	 * Offset of the Wacom-style device ID byte in the report, to be set
+	 * to pad device ID (0xf), for compatibility with Wacom drivers. Zero
+	 * if no changes to the report should be made. Only valid if "id" is
+	 * not zero.
+	 */
+	unsigned int dev_id_byte;
+};
+
+/*
+ * Tablet interface report parameters.
+ *
+ * Must use declarative (descriptive) language, not imperative, to simplify
+ * understanding and maintain consistency.
+ *
+ * When filled with zeros represents a "noop" configuration - passes all
+ * reports unchanged and lets the generic HID driver handle everything.
+ *
+ * The resulting device report descriptor is assembled from all the report
+ * descriptor parts referenced by the structure. No order of assembly should
+ * be assumed. The structure represents original device report descriptor if
+ * all the parts are NULL.
+ */
+struct uclogic_params {
+	/*
+	 * True if the whole interface is invalid, false otherwise.
+	 */
+	bool invalid;
+	/*
+	 * Pointer to the common part of the replacement report descriptor,
+	 * allocated with kmalloc. NULL if no common part is needed.
+	 * Only valid, if "invalid" is false.
+	 */
+	__u8 *desc_ptr;
+	/*
+	 * Size of the common part of the replacement report descriptor.
+	 * Only valid, if "desc_ptr" is not NULL.
+	 */
+	unsigned int desc_size;
+	/*
+	 * True, if pen usage in report descriptor is invalid, when present.
+	 * Only valid, if "invalid" is false.
+	 */
+	bool pen_unused;
+	/*
+	 * Pen parameters and optional report descriptor part.
+	 * Only valid if "pen_unused" is valid and false.
+	 */
+	struct uclogic_params_pen pen;
+	/*
+	 * Frame control parameters and optional report descriptor part.
+	 * Only valid, if "invalid" is false.
+	 */
+	struct uclogic_params_frame frame;
+	/*
+	 * Bitmask matching frame controls "sub-report" flag in the second
+	 * byte of the pen report, or zero if it's not expected.
+	 * Only valid if both "pen" and "frame" are valid, and "frame.id" is
+	 * not zero.
+	 */
+	__u8 pen_frame_flag;
+};
+
+/* Initialize a tablet interface and discover its parameters */
+extern int uclogic_params_init(struct uclogic_params *params,
+				struct hid_device *hdev);
+
+/* Tablet interface parameters *printf format string */
+#define UCLOGIC_PARAMS_FMT_STR \
+		".invalid = %s\n"                   \
+		".desc_ptr = %p\n"                  \
+		".desc_size = %u\n"                 \
+		".pen_unused = %s\n"                \
+		".pen.desc_ptr = %p\n"              \
+		".pen.desc_size = %u\n"             \
+		".pen.id = %u\n"                    \
+		".pen.inrange = %s\n"               \
+		".pen.fragmented_hires = %s\n"      \
+		".frame.desc_ptr = %p\n"            \
+		".frame.desc_size = %u\n"           \
+		".frame.id = %u\n"                  \
+		".frame.re_lsb = %u\n"              \
+		".frame.dev_id_byte = %u\n"         \
+		".pen_frame_flag = 0x%02x\n"
+
+/* Tablet interface parameters *printf format arguments */
+#define UCLOGIC_PARAMS_FMT_ARGS(_params) \
+		((_params)->invalid ? "true" : "false"),                    \
+		(_params)->desc_ptr,                                        \
+		(_params)->desc_size,                                       \
+		((_params)->pen_unused ? "true" : "false"),                 \
+		(_params)->pen.desc_ptr,                                    \
+		(_params)->pen.desc_size,                                   \
+		(_params)->pen.id,                                          \
+		uclogic_params_pen_inrange_to_str((_params)->pen.inrange),  \
+		((_params)->pen.fragmented_hires ? "true" : "false"),       \
+		(_params)->frame.desc_ptr,                                  \
+		(_params)->frame.desc_size,                                 \
+		(_params)->frame.id,                                        \
+		(_params)->frame.re_lsb,                                    \
+		(_params)->frame.dev_id_byte,                               \
+		(_params)->pen_frame_flag
+
+/* Get a replacement report descriptor for a tablet's interface. */
+extern int uclogic_params_get_desc(const struct uclogic_params *params,
+					__u8 **pdesc,
+					unsigned int *psize);
+
+/* Free resources used by tablet interface's parameters */
+extern void uclogic_params_cleanup(struct uclogic_params *params);
+
+#endif /* _HID_UCLOGIC_PARAMS_H */

drivers/hid/hid-uclogic.c → drivers/hid/hid-uclogic-rdesc.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  *  HID driver for UC-Logic devices not fully compliant with HID standard
+ *  - original and fixed report descriptors
  *
- *  Copyright (c) 2010-2014 Nikolai Kondrashov
+ *  Copyright (c) 2010-2017 Nikolai Kondrashov
  *  Copyright (c) 2013 Martin Rusko
  */
 
@@ -12,20 +14,12 @@
  * any later version.
  */
 
-#include <linux/device.h>
-#include <linux/hid.h>
-#include <linux/module.h>
-#include <linux/usb.h>
+#include "hid-uclogic-rdesc.h"
+#include <linux/slab.h>
 #include <asm/unaligned.h>
-#include "usbhid/usbhid.h"
-
-#include "hid-ids.h"
-
-/* Size of the original descriptor of WPXXXXU tablets */
-#define WPXXXXU_RDESC_ORIG_SIZE	212
 
 /* Fixed WP4030U report descriptor */
-static __u8 wp4030u_rdesc_fixed[] = {
+__u8 uclogic_rdesc_wp4030u_fixed_arr[] = {
 	0x05, 0x0D,         /*  Usage Page (Digitizer),             */
 	0x09, 0x02,         /*  Usage (Pen),                        */
 	0xA1, 0x01,         /*  Collection (Application),           */
@@ -66,8 +60,11 @@ static __u8 wp4030u_rdesc_fixed[] = {
 	0xC0                /*  End Collection                      */
 };
 
+const size_t uclogic_rdesc_wp4030u_fixed_size =
+			sizeof(uclogic_rdesc_wp4030u_fixed_arr);
+
 /* Fixed WP5540U report descriptor */
-static __u8 wp5540u_rdesc_fixed[] = {
+__u8 uclogic_rdesc_wp5540u_fixed_arr[] = {
 	0x05, 0x0D,         /*  Usage Page (Digitizer),             */
 	0x09, 0x02,         /*  Usage (Pen),                        */
 	0xA1, 0x01,         /*  Collection (Application),           */
@@ -140,8 +137,11 @@ static __u8 wp5540u_rdesc_fixed[] = {
 	0xC0                /*  End Collection                      */
 };
 
+const size_t uclogic_rdesc_wp5540u_fixed_size =
+			sizeof(uclogic_rdesc_wp5540u_fixed_arr);
+
 /* Fixed WP8060U report descriptor */
-static __u8 wp8060u_rdesc_fixed[] = {
+__u8 uclogic_rdesc_wp8060u_fixed_arr[] = {
 	0x05, 0x0D,         /*  Usage Page (Digitizer),             */
 	0x09, 0x02,         /*  Usage (Pen),                        */
 	0xA1, 0x01,         /*  Collection (Application),           */
@@ -214,11 +214,11 @@ static __u8 wp8060u_rdesc_fixed[] = {
 	0xC0                /*  End Collection                      */
 };
 
-/* Size of the original descriptor of WP1062 tablet */
-#define WP1062_RDESC_ORIG_SIZE	254
+const size_t uclogic_rdesc_wp8060u_fixed_size =
+			sizeof(uclogic_rdesc_wp8060u_fixed_arr);
 
 /* Fixed WP1062 report descriptor */
-static __u8 wp1062_rdesc_fixed[] = {
+__u8 uclogic_rdesc_wp1062_fixed_arr[] = {
 	0x05, 0x0D,         /*  Usage Page (Digitizer),             */
 	0x09, 0x02,         /*  Usage (Pen),                        */
 	0xA1, 0x01,         /*  Collection (Application),           */
@@ -262,11 +262,11 @@ static __u8 wp1062_rdesc_fixed[] = {
 	0xC0                /*  End Collection                      */
 };
 
-/* Size of the original descriptor of PF1209 tablet */
-#define PF1209_RDESC_ORIG_SIZE	234
+const size_t uclogic_rdesc_wp1062_fixed_size =
+			sizeof(uclogic_rdesc_wp1062_fixed_arr);
 
 /* Fixed PF1209 report descriptor */
-static __u8 pf1209_rdesc_fixed[] = {
+__u8 uclogic_rdesc_pf1209_fixed_arr[] = {
 	0x05, 0x0D,         /*  Usage Page (Digitizer),             */
 	0x09, 0x02,         /*  Usage (Pen),                        */
 	0xA1, 0x01,         /*  Collection (Application),           */
@@ -339,13 +339,11 @@ static __u8 pf1209_rdesc_fixed[] = {
 	0xC0                /*  End Collection                      */
 };
 
-/* Size of the original descriptors of TWHL850 tablet */
-#define TWHL850_RDESC_ORIG_SIZE0	182
-#define TWHL850_RDESC_ORIG_SIZE1	161
-#define TWHL850_RDESC_ORIG_SIZE2	92
+const size_t uclogic_rdesc_pf1209_fixed_size =
+			sizeof(uclogic_rdesc_pf1209_fixed_arr);
 
 /* Fixed PID 0522 tablet report descriptor, interface 0 (stylus) */
-static __u8 twhl850_rdesc_fixed0[] = {
+__u8 uclogic_rdesc_twhl850_fixed0_arr[] = {
 	0x05, 0x0D,         /*  Usage Page (Digitizer),             */
 	0x09, 0x02,         /*  Usage (Pen),                        */
 	0xA1, 0x01,         /*  Collection (Application),           */
@@ -387,8 +385,11 @@ static __u8 twhl850_rdesc_fixed0[] = {
 	0xC0                /*  End Collection                      */
 };
 
+const size_t uclogic_rdesc_twhl850_fixed0_size =
+			sizeof(uclogic_rdesc_twhl850_fixed0_arr);
+
 /* Fixed PID 0522 tablet report descriptor, interface 1 (mouse) */
-static __u8 twhl850_rdesc_fixed1[] = {
+__u8 uclogic_rdesc_twhl850_fixed1_arr[] = {
 	0x05, 0x01,         /*  Usage Page (Desktop),               */
 	0x09, 0x02,         /*  Usage (Mouse),                      */
 	0xA1, 0x01,         /*  Collection (Application),           */
@@ -424,8 +425,11 @@ static __u8 twhl850_rdesc_fixed1[] = {
 	0xC0                /*  End Collection                      */
 };
 
+const size_t uclogic_rdesc_twhl850_fixed1_size =
+			sizeof(uclogic_rdesc_twhl850_fixed1_arr);
+
 /* Fixed PID 0522 tablet report descriptor, interface 2 (frame buttons) */
-static __u8 twhl850_rdesc_fixed2[] = {
+__u8 uclogic_rdesc_twhl850_fixed2_arr[] = {
 	0x05, 0x01,         /*  Usage Page (Desktop),               */
 	0x09, 0x06,         /*  Usage (Keyboard),                   */
 	0xA1, 0x01,         /*  Collection (Application),           */
@@ -447,12 +451,11 @@ static __u8 twhl850_rdesc_fixed2[] = {
 	0xC0                /*  End Collection                      */
 };
 
-/* Size of the original descriptors of TWHA60 tablet */
-#define TWHA60_RDESC_ORIG_SIZE0 254
-#define TWHA60_RDESC_ORIG_SIZE1 139
+const size_t uclogic_rdesc_twhl850_fixed2_size =
+			sizeof(uclogic_rdesc_twhl850_fixed2_arr);
 
 /* Fixed TWHA60 report descriptor, interface 0 (stylus) */
-static __u8 twha60_rdesc_fixed0[] = {
+__u8 uclogic_rdesc_twha60_fixed0_arr[] = {
 	0x05, 0x0D,         /*  Usage Page (Digitizer),             */
 	0x09, 0x02,         /*  Usage (Pen),                        */
 	0xA1, 0x01,         /*  Collection (Application),           */
@@ -497,8 +500,11 @@ static __u8 twha60_rdesc_fixed0[] = {
 	0xC0                /*  End Collection                      */
 };
 
+const size_t uclogic_rdesc_twha60_fixed0_size =
+			sizeof(uclogic_rdesc_twha60_fixed0_arr);
+
 /* Fixed TWHA60 report descriptor, interface 1 (frame buttons) */
-static __u8 twha60_rdesc_fixed1[] = {
+__u8 uclogic_rdesc_twha60_fixed1_arr[] = {
 	0x05, 0x01, /*  Usage Page (Desktop),       */
 	0x09, 0x06, /*  Usage (Keyboard),           */
 	0xA1, 0x01, /*  Collection (Application),   */
@@ -522,29 +528,69 @@ static __u8 twha60_rdesc_fixed1[] = {
 	0xC0        /*  End Collection              */
 };
 
-/* Report descriptor template placeholder head */
-#define UCLOGIC_PH_HEAD	0xFE, 0xED, 0x1D
+const size_t uclogic_rdesc_twha60_fixed1_size =
+			sizeof(uclogic_rdesc_twha60_fixed1_arr);
 
-/* Report descriptor template placeholder IDs */
-enum uclogic_ph_id {
-	UCLOGIC_PH_ID_X_LM,
-	UCLOGIC_PH_ID_X_PM,
-	UCLOGIC_PH_ID_Y_LM,
-	UCLOGIC_PH_ID_Y_PM,
-	UCLOGIC_PH_ID_PRESSURE_LM,
-	UCLOGIC_PH_ID_NUM
+/* Fixed report descriptor template for (tweaked) v1 pen reports */
+const __u8 uclogic_rdesc_pen_v1_template_arr[] = {
+	0x05, 0x0D,             /*  Usage Page (Digitizer),                 */
+	0x09, 0x02,             /*  Usage (Pen),                            */
+	0xA1, 0x01,             /*  Collection (Application),               */
+	0x85, 0x07,             /*      Report ID (7),                      */
+	0x09, 0x20,             /*      Usage (Stylus),                     */
+	0xA0,                   /*      Collection (Physical),              */
+	0x14,                   /*          Logical Minimum (0),            */
+	0x25, 0x01,             /*          Logical Maximum (1),            */
+	0x75, 0x01,             /*          Report Size (1),                */
+	0x09, 0x42,             /*          Usage (Tip Switch),             */
+	0x09, 0x44,             /*          Usage (Barrel Switch),          */
+	0x09, 0x46,             /*          Usage (Tablet Pick),            */
+	0x95, 0x03,             /*          Report Count (3),               */
+	0x81, 0x02,             /*          Input (Variable),               */
+	0x95, 0x03,             /*          Report Count (3),               */
+	0x81, 0x03,             /*          Input (Constant, Variable),     */
+	0x09, 0x32,             /*          Usage (In Range),               */
+	0x95, 0x01,             /*          Report Count (1),               */
+	0x81, 0x02,             /*          Input (Variable),               */
+	0x95, 0x01,             /*          Report Count (1),               */
+	0x81, 0x03,             /*          Input (Constant, Variable),     */
+	0x75, 0x10,             /*          Report Size (16),               */
+	0x95, 0x01,             /*          Report Count (1),               */
+	0xA4,                   /*          Push,                           */
+	0x05, 0x01,             /*          Usage Page (Desktop),           */
+	0x65, 0x13,             /*          Unit (Inch),                    */
+	0x55, 0xFD,             /*          Unit Exponent (-3),             */
+	0x34,                   /*          Physical Minimum (0),           */
+	0x09, 0x30,             /*          Usage (X),                      */
+	0x27, UCLOGIC_RDESC_PEN_PH(X_LM),
+				/*          Logical Maximum (PLACEHOLDER),  */
+	0x47, UCLOGIC_RDESC_PEN_PH(X_PM),
+				/*          Physical Maximum (PLACEHOLDER), */
+	0x81, 0x02,             /*          Input (Variable),               */
+	0x09, 0x31,             /*          Usage (Y),                      */
+	0x27, UCLOGIC_RDESC_PEN_PH(Y_LM),
+				/*          Logical Maximum (PLACEHOLDER),  */
+	0x47, UCLOGIC_RDESC_PEN_PH(Y_PM),
+				/*          Physical Maximum (PLACEHOLDER), */
+	0x81, 0x02,             /*          Input (Variable),               */
+	0xB4,                   /*          Pop,                            */
+	0x09, 0x30,             /*          Usage (Tip Pressure),           */
+	0x27, UCLOGIC_RDESC_PEN_PH(PRESSURE_LM),
+				/*          Logical Maximum (PLACEHOLDER),  */
+	0x81, 0x02,             /*          Input (Variable),               */
+	0xC0,                   /*      End Collection,                     */
+	0xC0                    /*  End Collection                          */
 };
 
-/* Report descriptor template placeholder */
-#define UCLOGIC_PH(_ID) UCLOGIC_PH_HEAD, UCLOGIC_PH_ID_##_ID
-#define UCLOGIC_PEN_REPORT_ID	0x07
+const size_t uclogic_rdesc_pen_v1_template_size =
+			sizeof(uclogic_rdesc_pen_v1_template_arr);
 
-/* Fixed report descriptor template */
-static const __u8 uclogic_tablet_rdesc_template[] = {
+/* Fixed report descriptor template for (tweaked) v2 pen reports */
+const __u8 uclogic_rdesc_pen_v2_template_arr[] = {
 	0x05, 0x0D,             /*  Usage Page (Digitizer),                 */
 	0x09, 0x02,             /*  Usage (Pen),                            */
 	0xA1, 0x01,             /*  Collection (Application),               */
-	0x85, 0x07,             /*      Report ID (7),                      */
+	0x85, 0x08,             /*      Report ID (8),                      */
 	0x09, 0x20,             /*      Usage (Stylus),                     */
 	0xA0,                   /*      Collection (Physical),              */
 	0x14,                   /*          Logical Minimum (0),            */
@@ -562,529 +608,255 @@ static const __u8 uclogic_tablet_rdesc_template[] = {
 	0x81, 0x02,             /*          Input (Variable),               */
 	0x95, 0x01,             /*          Report Count (1),               */
 	0x81, 0x03,             /*          Input (Constant, Variable),     */
-	0x75, 0x10,             /*          Report Size (16),               */
 	0x95, 0x01,             /*          Report Count (1),               */
 	0xA4,                   /*          Push,                           */
 	0x05, 0x01,             /*          Usage Page (Desktop),           */
 	0x65, 0x13,             /*          Unit (Inch),                    */
 	0x55, 0xFD,             /*          Unit Exponent (-3),             */
+	0x75, 0x18,             /*          Report Size (24),               */
 	0x34,                   /*          Physical Minimum (0),           */
 	0x09, 0x30,             /*          Usage (X),                      */
-	0x27, UCLOGIC_PH(X_LM), /*          Logical Maximum (PLACEHOLDER),  */
-	0x47, UCLOGIC_PH(X_PM), /*          Physical Maximum (PLACEHOLDER), */
+	0x27, UCLOGIC_RDESC_PEN_PH(X_LM),
+				/*          Logical Maximum (PLACEHOLDER),  */
+	0x47, UCLOGIC_RDESC_PEN_PH(X_PM),
+				/*          Physical Maximum (PLACEHOLDER), */
 	0x81, 0x02,             /*          Input (Variable),               */
 	0x09, 0x31,             /*          Usage (Y),                      */
-	0x27, UCLOGIC_PH(Y_LM), /*          Logical Maximum (PLACEHOLDER),  */
-	0x47, UCLOGIC_PH(Y_PM), /*          Physical Maximum (PLACEHOLDER), */
+	0x27, UCLOGIC_RDESC_PEN_PH(Y_LM),
+				/*          Logical Maximum (PLACEHOLDER),  */
+	0x47, UCLOGIC_RDESC_PEN_PH(Y_PM),
+				/*          Physical Maximum (PLACEHOLDER), */
 	0x81, 0x02,             /*          Input (Variable),               */
 	0xB4,                   /*          Pop,                            */
 	0x09, 0x30,             /*          Usage (Tip Pressure),           */
-	0x27,
-	UCLOGIC_PH(PRESSURE_LM),/*          Logical Maximum (PLACEHOLDER),  */
+	0x75, 0x10,             /*          Report Size (16),               */
+	0x27, UCLOGIC_RDESC_PEN_PH(PRESSURE_LM),
+				/*          Logical Maximum (PLACEHOLDER),  */
 	0x81, 0x02,             /*          Input (Variable),               */
+	0x81, 0x03,             /*          Input (Constant, Variable),     */
 	0xC0,                   /*      End Collection,                     */
 	0xC0                    /*  End Collection                          */
 };
 
-/* Fixed virtual pad report descriptor */
-static const __u8 uclogic_buttonpad_rdesc[] = {
+const size_t uclogic_rdesc_pen_v2_template_size =
+			sizeof(uclogic_rdesc_pen_v2_template_arr);
+
+/**
+ * Expand to the contents of a generic buttonpad report descriptor.
+ *
+ * @_padding:	Padding from the end of button bits at bit 44, until
+ *		the end of the report, in bits.
+ */
+#define UCLOGIC_RDESC_BUTTONPAD_BYTES(_padding) \
+	0x05, 0x01,     /*  Usage Page (Desktop),               */ \
+	0x09, 0x07,     /*  Usage (Keypad),                     */ \
+	0xA1, 0x01,     /*  Collection (Application),           */ \
+	0x85, 0xF7,     /*      Report ID (247),                */ \
+	0x14,           /*      Logical Minimum (0),            */ \
+	0x25, 0x01,     /*      Logical Maximum (1),            */ \
+	0x75, 0x01,     /*      Report Size (1),                */ \
+	0x05, 0x0D,     /*      Usage Page (Digitizer),         */ \
+	0x09, 0x39,     /*      Usage (Tablet Function Keys),   */ \
+	0xA0,           /*      Collection (Physical),          */ \
+	0x09, 0x44,     /*          Usage (Barrel Switch),      */ \
+	0x95, 0x01,     /*          Report Count (1),           */ \
+	0x81, 0x02,     /*          Input (Variable),           */ \
+	0x05, 0x01,     /*          Usage Page (Desktop),       */ \
+	0x09, 0x30,     /*          Usage (X),                  */ \
+	0x09, 0x31,     /*          Usage (Y),                  */ \
+	0x95, 0x02,     /*          Report Count (2),           */ \
+	0x81, 0x02,     /*          Input (Variable),           */ \
+	0x95, 0x15,     /*          Report Count (21),          */ \
+	0x81, 0x01,     /*          Input (Constant),           */ \
+	0x05, 0x09,     /*          Usage Page (Button),        */ \
+	0x19, 0x01,     /*          Usage Minimum (01h),        */ \
+	0x29, 0x0A,     /*          Usage Maximum (0Ah),        */ \
+	0x95, 0x0A,     /*          Report Count (10),          */ \
+	0x81, 0x02,     /*          Input (Variable),           */ \
+	0xC0,           /*      End Collection,                 */ \
+	0x05, 0x01,     /*      Usage Page (Desktop),           */ \
+	0x09, 0x05,     /*      Usage (Gamepad),                */ \
+	0xA0,           /*      Collection (Physical),          */ \
+	0x05, 0x09,     /*          Usage Page (Button),        */ \
+	0x19, 0x01,     /*          Usage Minimum (01h),        */ \
+	0x29, 0x02,     /*          Usage Maximum (02h),        */ \
+	0x95, 0x02,     /*          Report Count (2),           */ \
+	0x81, 0x02,     /*          Input (Variable),           */ \
+	0x95, _padding, /*          Report Count (_padding),    */ \
+	0x81, 0x01,     /*          Input (Constant),           */ \
+	0xC0,           /*      End Collection,                 */ \
+	0xC0            /*  End Collection                      */
+
+/* Fixed report descriptor for (tweaked) v1 buttonpad reports */
+const __u8 uclogic_rdesc_buttonpad_v1_arr[] = {
+	UCLOGIC_RDESC_BUTTONPAD_BYTES(20)
+};
+const size_t uclogic_rdesc_buttonpad_v1_size =
+			sizeof(uclogic_rdesc_buttonpad_v1_arr);
+
+/* Fixed report descriptor for (tweaked) v2 buttonpad reports */
+const __u8 uclogic_rdesc_buttonpad_v2_arr[] = {
+	UCLOGIC_RDESC_BUTTONPAD_BYTES(52)
+};
+const size_t uclogic_rdesc_buttonpad_v2_size =
+			sizeof(uclogic_rdesc_buttonpad_v2_arr);
+
+/* Fixed report descriptor for Ugee EX07 buttonpad */
+const __u8 uclogic_rdesc_ugee_ex07_buttonpad_arr[] = {
 	0x05, 0x01,             /*  Usage Page (Desktop),                   */
 	0x09, 0x07,             /*  Usage (Keypad),                         */
 	0xA1, 0x01,             /*  Collection (Application),               */
-	0x85, 0xF7,             /*      Report ID (247),                    */
-	0x05, 0x0D,             /*      Usage Page (Digitizers),            */
+	0x85, 0x06,             /*      Report ID (6),                      */
+	0x05, 0x0D,             /*      Usage Page (Digitizer),             */
 	0x09, 0x39,             /*      Usage (Tablet Function Keys),       */
 	0xA0,                   /*      Collection (Physical),              */
 	0x05, 0x09,             /*          Usage Page (Button),            */
 	0x75, 0x01,             /*          Report Size (1),                */
-	0x95, 0x18,             /*          Report Count (24),              */
+	0x19, 0x03,             /*          Usage Minimum (03h),            */
+	0x29, 0x06,             /*          Usage Maximum (06h),            */
+	0x95, 0x04,             /*          Report Count (4),               */
+	0x81, 0x02,             /*          Input (Variable),               */
+	0x95, 0x1A,             /*          Report Count (26),              */
 	0x81, 0x03,             /*          Input (Constant, Variable),     */
 	0x19, 0x01,             /*          Usage Minimum (01h),            */
-	0x29, 0x08,             /*          Usage Maximum (08h),            */
-	0x95, 0x08,             /*          Report Count (8),               */
+	0x29, 0x02,             /*          Usage Maximum (02h),            */
+	0x95, 0x02,             /*          Report Count (2),               */
 	0x81, 0x02,             /*          Input (Variable),               */
-	0xC0,                   /*      End Collection                      */
+	0xC0,                   /*      End Collection,                     */
 	0xC0                    /*  End Collection                          */
 };
+const size_t uclogic_rdesc_ugee_ex07_buttonpad_size =
+			sizeof(uclogic_rdesc_ugee_ex07_buttonpad_arr);
 
-/* Parameter indices */
-enum uclogic_prm {
-	UCLOGIC_PRM_X_LM	= 1,
-	UCLOGIC_PRM_Y_LM	= 2,
-	UCLOGIC_PRM_PRESSURE_LM	= 4,
-	UCLOGIC_PRM_RESOLUTION	= 5,
-	UCLOGIC_PRM_NUM
+/* Fixed report descriptor for Ugee G5 frame controls */
+const __u8 uclogic_rdesc_ugee_g5_frame_arr[] = {
+	0x05, 0x01,         /*  Usage Page (Desktop),               */
+	0x09, 0x07,         /*  Usage (Keypad),                     */
+	0xA1, 0x01,         /*  Collection (Application),           */
+	0x85, 0x06,         /*      Report ID (6),                  */
+	0x05, 0x0D,         /*      Usage Page (Digitizer),         */
+	0x09, 0x39,         /*      Usage (Tablet Function Keys),   */
+	0xA0,               /*      Collection (Physical),          */
+	0x14,               /*          Logical Minimum (0),        */
+	0x25, 0x01,         /*          Logical Maximum (1),        */
+	0x05, 0x01,         /*          Usage Page (Desktop),       */
+	0x05, 0x09,         /*          Usage Page (Button),        */
+	0x19, 0x01,         /*          Usage Minimum (01h),        */
+	0x29, 0x05,         /*          Usage Maximum (05h),        */
+	0x75, 0x01,         /*          Report Size (1),            */
+	0x95, 0x05,         /*          Report Count (5),           */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0x75, 0x01,         /*          Report Size (1),            */
+	0x95, 0x03,         /*          Report Count (3),           */
+	0x81, 0x01,         /*          Input (Constant),           */
+	0x05, 0x0D,         /*          Usage Page (Digitizer),     */
+	0x0A, 0xFF, 0xFF,   /*          Usage (FFFFh),              */
+	0x26, 0xFF, 0x00,   /*          Logical Maximum (255),      */
+	0x75, 0x08,         /*          Report Size (8),            */
+	0x95, 0x01,         /*          Report Count (1),           */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0x25, 0x01,         /*          Logical Maximum (1),        */
+	0x09, 0x44,         /*          Usage (Barrel Switch),      */
+	0x75, 0x01,         /*          Report Size (1),            */
+	0x95, 0x01,         /*          Report Count (1),           */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0x05, 0x01,         /*          Usage Page (Desktop),       */
+	0x09, 0x30,         /*          Usage (X),                  */
+	0x09, 0x31,         /*          Usage (Y),                  */
+	0x75, 0x01,         /*          Report Size (1),            */
+	0x95, 0x02,         /*          Report Count (2),           */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0x75, 0x01,         /*          Report Size (1),            */
+	0x95, 0x0B,         /*          Report Count (11),          */
+	0x81, 0x01,         /*          Input (Constant),           */
+	0x05, 0x01,         /*          Usage Page (Desktop),       */
+	0x09, 0x38,         /*          Usage (Wheel),              */
+	0x15, 0xFF,         /*          Logical Minimum (-1),       */
+	0x25, 0x01,         /*          Logical Maximum (1),        */
+	0x75, 0x02,         /*          Report Size (2),            */
+	0x95, 0x01,         /*          Report Count (1),           */
+	0x81, 0x06,         /*          Input (Variable, Relative), */
+	0xC0,               /*      End Collection,                 */
+	0xC0                /*  End Collection                      */
 };
+const size_t uclogic_rdesc_ugee_g5_frame_size =
+			sizeof(uclogic_rdesc_ugee_g5_frame_arr);
 
-/* Driver data */
-struct uclogic_drvdata {
-	__u8 *rdesc;
-	unsigned int rsize;
-	bool invert_pen_inrange;
-	bool ignore_pen_usage;
-	bool has_virtual_pad_interface;
+/* Fixed report descriptor for XP-Pen Deco 01 frame controls */
+const __u8 uclogic_rdesc_xppen_deco01_frame_arr[] = {
+	0x05, 0x01, /*  Usage Page (Desktop),               */
+	0x09, 0x07, /*  Usage (Keypad),                     */
+	0xA1, 0x01, /*  Collection (Application),           */
+	0x85, 0x06, /*      Report ID (6),                  */
+	0x14,       /*      Logical Minimum (0),            */
+	0x25, 0x01, /*      Logical Maximum (1),            */
+	0x75, 0x01, /*      Report Size (1),                */
+	0x05, 0x0D, /*      Usage Page (Digitizer),         */
+	0x09, 0x39, /*      Usage (Tablet Function Keys),   */
+	0xA0,       /*      Collection (Physical),          */
+	0x05, 0x09, /*          Usage Page (Button),        */
+	0x19, 0x01, /*          Usage Minimum (01h),        */
+	0x29, 0x08, /*          Usage Maximum (08h),        */
+	0x95, 0x08, /*          Report Count (8),           */
+	0x81, 0x02, /*          Input (Variable),           */
+	0x05, 0x0D, /*          Usage Page (Digitizer),     */
+	0x09, 0x44, /*          Usage (Barrel Switch),      */
+	0x95, 0x01, /*          Report Count (1),           */
+	0x81, 0x02, /*          Input (Variable),           */
+	0x05, 0x01, /*          Usage Page (Desktop),       */
+	0x09, 0x30, /*          Usage (X),                  */
+	0x09, 0x31, /*          Usage (Y),                  */
+	0x95, 0x02, /*          Report Count (2),           */
+	0x81, 0x02, /*          Input (Variable),           */
+	0x95, 0x15, /*          Report Count (21),          */
+	0x81, 0x01, /*          Input (Constant),           */
+	0xC0,       /*      End Collection,                 */
+	0xC0        /*  End Collection                      */
 };
 
-static __u8 *uclogic_report_fixup(struct hid_device *hdev, __u8 *rdesc,
-					unsigned int *rsize)
-{
-	struct usb_interface *iface = to_usb_interface(hdev->dev.parent);
-	__u8 iface_num = iface->cur_altsetting->desc.bInterfaceNumber;
-	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
-
-	if (drvdata->rdesc != NULL) {
-		rdesc = drvdata->rdesc;
-		*rsize = drvdata->rsize;
-		return rdesc;
-	}
-
-	switch (hdev->product) {
-	case USB_DEVICE_ID_UCLOGIC_TABLET_PF1209:
-		if (*rsize == PF1209_RDESC_ORIG_SIZE) {
-			rdesc = pf1209_rdesc_fixed;
-			*rsize = sizeof(pf1209_rdesc_fixed);
-		}
-		break;
-	case USB_DEVICE_ID_UCLOGIC_TABLET_WP4030U:
-		if (*rsize == WPXXXXU_RDESC_ORIG_SIZE) {
-			rdesc = wp4030u_rdesc_fixed;
-			*rsize = sizeof(wp4030u_rdesc_fixed);
-		}
-		break;
-	case USB_DEVICE_ID_UCLOGIC_TABLET_WP5540U:
-		if (*rsize == WPXXXXU_RDESC_ORIG_SIZE) {
-			rdesc = wp5540u_rdesc_fixed;
-			*rsize = sizeof(wp5540u_rdesc_fixed);
-		}
-		break;
-	case USB_DEVICE_ID_UCLOGIC_TABLET_WP8060U:
-		if (*rsize == WPXXXXU_RDESC_ORIG_SIZE) {
-			rdesc = wp8060u_rdesc_fixed;
-			*rsize = sizeof(wp8060u_rdesc_fixed);
-		}
-		break;
-	case USB_DEVICE_ID_UCLOGIC_TABLET_WP1062:
-		if (*rsize == WP1062_RDESC_ORIG_SIZE) {
-			rdesc = wp1062_rdesc_fixed;
-			*rsize = sizeof(wp1062_rdesc_fixed);
-		}
-		break;
-	case USB_DEVICE_ID_UCLOGIC_WIRELESS_TABLET_TWHL850:
-		switch (iface_num) {
-		case 0:
-			if (*rsize == TWHL850_RDESC_ORIG_SIZE0) {
-				rdesc = twhl850_rdesc_fixed0;
-				*rsize = sizeof(twhl850_rdesc_fixed0);
-			}
-			break;
-		case 1:
-			if (*rsize == TWHL850_RDESC_ORIG_SIZE1) {
-				rdesc = twhl850_rdesc_fixed1;
-				*rsize = sizeof(twhl850_rdesc_fixed1);
-			}
-			break;
-		case 2:
-			if (*rsize == TWHL850_RDESC_ORIG_SIZE2) {
-				rdesc = twhl850_rdesc_fixed2;
-				*rsize = sizeof(twhl850_rdesc_fixed2);
-			}
-			break;
-		}
-		break;
-	case USB_DEVICE_ID_UCLOGIC_TABLET_TWHA60:
-		switch (iface_num) {
-		case 0:
-			if (*rsize == TWHA60_RDESC_ORIG_SIZE0) {
-				rdesc = twha60_rdesc_fixed0;
-				*rsize = sizeof(twha60_rdesc_fixed0);
-			}
-			break;
-		case 1:
-			if (*rsize == TWHA60_RDESC_ORIG_SIZE1) {
-				rdesc = twha60_rdesc_fixed1;
-				*rsize = sizeof(twha60_rdesc_fixed1);
-			}
-			break;
-		}
-		break;
-	}
-
-	return rdesc;
-}
-
-static int uclogic_input_mapping(struct hid_device *hdev, struct hid_input *hi,
-		struct hid_field *field, struct hid_usage *usage,
-		unsigned long **bit, int *max)
-{
-	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
-
-	/* discard the unused pen interface */
-	if ((drvdata->ignore_pen_usage) &&
-	    (field->application == HID_DG_PEN))
-		return -1;
-
-	/* let hid-core decide what to do */
-	return 0;
-}
-
-static int uclogic_input_configured(struct hid_device *hdev,
-		struct hid_input *hi)
-{
-	char *name;
-	const char *suffix = NULL;
-	struct hid_field *field;
-	size_t len;
-
-	/* no report associated (HID_QUIRK_MULTI_INPUT not set) */
-	if (!hi->report)
-		return 0;
-
-	field = hi->report->field[0];
-
-	switch (field->application) {
-	case HID_GD_KEYBOARD:
-		suffix = "Keyboard";
-		break;
-	case HID_GD_MOUSE:
-		suffix = "Mouse";
-		break;
-	case HID_GD_KEYPAD:
-		suffix = "Pad";
-		break;
-	case HID_DG_PEN:
-		suffix = "Pen";
-		break;
-	case HID_CP_CONSUMER_CONTROL:
-		suffix = "Consumer Control";
-		break;
-	case HID_GD_SYSTEM_CONTROL:
-		suffix = "System Control";
-		break;
-	}
-
-	if (suffix) {
-		len = strlen(hdev->name) + 2 + strlen(suffix);
-		name = devm_kzalloc(&hi->input->dev, len, GFP_KERNEL);
-		if (name) {
-			snprintf(name, len, "%s %s", hdev->name, suffix);
-			hi->input->name = name;
-		}
-	}
-
-	return 0;
-}
+const size_t uclogic_rdesc_xppen_deco01_frame_size =
+			sizeof(uclogic_rdesc_xppen_deco01_frame_arr);
 
 /**
- * Enable fully-functional tablet mode and determine device parameters.
+ * uclogic_rdesc_template_apply() - apply report descriptor parameters to a
+ * report descriptor template, creating a report descriptor. Copies the
+ * template over to the new report descriptor and replaces every occurrence of
+ * UCLOGIC_RDESC_PH_HEAD, followed by an index byte, with the value from the
+ * parameter list at that index.
  *
- * @hdev:	HID device
+ * @template_ptr:	Pointer to the template buffer.
+ * @template_size:	Size of the template buffer.
+ * @param_list:		List of template parameters.
+ * @param_num:		Number of parameters in the list.
+ *
+ * Returns:
+ *	Kmalloc-allocated pointer to the created report descriptor,
+ *	or NULL if allocation failed.
  */
-static int uclogic_tablet_enable(struct hid_device *hdev)
+__u8 *uclogic_rdesc_template_apply(const __u8 *template_ptr,
+				   size_t template_size,
+				   const s32 *param_list,
+				   size_t param_num)
 {
-	int rc;
-	struct usb_device *usb_dev = hid_to_usb_dev(hdev);
-	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
-	__le16 *buf = NULL;
-	size_t len;
-	s32 params[UCLOGIC_PH_ID_NUM];
-	s32 resolution;
+	static const __u8 head[] = {UCLOGIC_RDESC_PH_HEAD};
+	__u8 *rdesc_ptr;
 	__u8 *p;
 	s32 v;
 
-	/*
-	 * Read string descriptor containing tablet parameters. The specific
-	 * string descriptor and data were discovered by sniffing the Windows
-	 * driver traffic.
-	 * NOTE: This enables fully-functional tablet mode.
-	 */
-	len = UCLOGIC_PRM_NUM * sizeof(*buf);
-	buf = kmalloc(len, GFP_KERNEL);
-	if (buf == NULL) {
-		rc = -ENOMEM;
-		goto cleanup;
-	}
-	rc = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
-				USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
-				(USB_DT_STRING << 8) + 0x64,
-				0x0409, buf, len,
-				USB_CTRL_GET_TIMEOUT);
-	if (rc == -EPIPE) {
-		hid_err(hdev, "device parameters not found\n");
-		rc = -ENODEV;
-		goto cleanup;
-	} else if (rc < 0) {
-		hid_err(hdev, "failed to get device parameters: %d\n", rc);
-		rc = -ENODEV;
-		goto cleanup;
-	} else if (rc != len) {
-		hid_err(hdev, "invalid device parameters\n");
-		rc = -ENODEV;
-		goto cleanup;
-	}
-
-	/* Extract device parameters */
-	params[UCLOGIC_PH_ID_X_LM] = le16_to_cpu(buf[UCLOGIC_PRM_X_LM]);
-	params[UCLOGIC_PH_ID_Y_LM] = le16_to_cpu(buf[UCLOGIC_PRM_Y_LM]);
-	params[UCLOGIC_PH_ID_PRESSURE_LM] =
-		le16_to_cpu(buf[UCLOGIC_PRM_PRESSURE_LM]);
-	resolution = le16_to_cpu(buf[UCLOGIC_PRM_RESOLUTION]);
-	if (resolution == 0) {
-		params[UCLOGIC_PH_ID_X_PM] = 0;
-		params[UCLOGIC_PH_ID_Y_PM] = 0;
-	} else {
-		params[UCLOGIC_PH_ID_X_PM] = params[UCLOGIC_PH_ID_X_LM] *
-						1000 / resolution;
-		params[UCLOGIC_PH_ID_Y_PM] = params[UCLOGIC_PH_ID_Y_LM] *
-						1000 / resolution;
-	}
+	rdesc_ptr = kmemdup(template_ptr, template_size, GFP_KERNEL);
+	if (rdesc_ptr == NULL)
+		return NULL;
 
-	/* Allocate fixed report descriptor */
-	drvdata->rdesc = devm_kzalloc(&hdev->dev,
-				sizeof(uclogic_tablet_rdesc_template),
-				GFP_KERNEL);
-	if (drvdata->rdesc == NULL) {
-		rc = -ENOMEM;
-		goto cleanup;
-	}
-	drvdata->rsize = sizeof(uclogic_tablet_rdesc_template);
-
-	/* Format fixed report descriptor */
-	memcpy(drvdata->rdesc, uclogic_tablet_rdesc_template,
-		drvdata->rsize);
-	for (p = drvdata->rdesc;
-	     p <= drvdata->rdesc + drvdata->rsize - 4;) {
-		if (p[0] == 0xFE && p[1] == 0xED && p[2] == 0x1D &&
-		    p[3] < ARRAY_SIZE(params)) {
-			v = params[p[3]];
+	for (p = rdesc_ptr; p + sizeof(head) < rdesc_ptr + template_size;) {
+		if (memcmp(p, head, sizeof(head)) == 0 &&
+		    p[sizeof(head)] < param_num) {
+			v = param_list[p[sizeof(head)]];
 			put_unaligned(cpu_to_le32(v), (s32 *)p);
-			p += 4;
+			p += sizeof(head) + 1;
 		} else {
 			p++;
 		}
 	}
 
-	rc = 0;
-
-cleanup:
-	kfree(buf);
-	return rc;
-}
-
-/**
- * Enable actual button mode.
- *
- * @hdev:	HID device
- */
-static int uclogic_button_enable(struct hid_device *hdev)
-{
-	int rc;
-	struct usb_device *usb_dev = hid_to_usb_dev(hdev);
-	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
-	char *str_buf;
-	size_t str_len = 16;
-	unsigned char *rdesc;
-	size_t rdesc_len;
-
-	str_buf = kzalloc(str_len, GFP_KERNEL);
-	if (str_buf == NULL) {
-		rc = -ENOMEM;
-		goto cleanup;
-	}
-
-	/* Enable abstract keyboard mode */
-	rc = usb_string(usb_dev, 0x7b, str_buf, str_len);
-	if (rc == -EPIPE) {
-		hid_info(hdev, "button mode setting not found\n");
-		rc = 0;
-		goto cleanup;
-	} else if (rc < 0) {
-		hid_err(hdev, "failed to enable abstract keyboard\n");
-		goto cleanup;
-	} else if (strncmp(str_buf, "HK On", rc)) {
-		hid_info(hdev, "invalid answer when requesting buttons: '%s'\n",
-			str_buf);
-		rc = -EINVAL;
-		goto cleanup;
-	}
-
-	/* Re-allocate fixed report descriptor */
-	rdesc_len = drvdata->rsize + sizeof(uclogic_buttonpad_rdesc);
-	rdesc = devm_kzalloc(&hdev->dev, rdesc_len, GFP_KERNEL);
-	if (!rdesc) {
-		rc = -ENOMEM;
-		goto cleanup;
-	}
-
-	memcpy(rdesc, drvdata->rdesc, drvdata->rsize);
-
-	/* Append the buttonpad descriptor */
-	memcpy(rdesc + drvdata->rsize, uclogic_buttonpad_rdesc,
-	       sizeof(uclogic_buttonpad_rdesc));
-
-	/* clean up old rdesc and use the new one */
-	drvdata->rsize = rdesc_len;
-	devm_kfree(&hdev->dev, drvdata->rdesc);
-	drvdata->rdesc = rdesc;
-
-	rc = 0;
-
-cleanup:
-	kfree(str_buf);
-	return rc;
-}
-
-static int uclogic_probe(struct hid_device *hdev,
-		const struct hid_device_id *id)
-{
-	int rc;
-	struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
-	struct usb_device *udev = hid_to_usb_dev(hdev);
-	struct uclogic_drvdata *drvdata;
-
-	/*
-	 * libinput requires the pad interface to be on a different node
-	 * than the pen, so use QUIRK_MULTI_INPUT for all tablets.
-	 */
-	hdev->quirks |= HID_QUIRK_MULTI_INPUT;
-
-	/* Allocate and assign driver data */
-	drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
-	if (drvdata == NULL)
-		return -ENOMEM;
-
-	hid_set_drvdata(hdev, drvdata);
-
-	switch (id->product) {
-	case USB_DEVICE_ID_HUION_TABLET:
-	case USB_DEVICE_ID_YIYNOVA_TABLET:
-	case USB_DEVICE_ID_UGEE_TABLET_81:
-	case USB_DEVICE_ID_UCLOGIC_DRAWIMAGE_G3:
-	case USB_DEVICE_ID_UGEE_TABLET_45:
-		/* If this is the pen interface */
-		if (intf->cur_altsetting->desc.bInterfaceNumber == 0) {
-			rc = uclogic_tablet_enable(hdev);
-			if (rc) {
-				hid_err(hdev, "tablet enabling failed\n");
-				return rc;
-			}
-			drvdata->invert_pen_inrange = true;
-
-			rc = uclogic_button_enable(hdev);
-			drvdata->has_virtual_pad_interface = !rc;
-		} else {
-			drvdata->ignore_pen_usage = true;
-		}
-		break;
-	case USB_DEVICE_ID_UGTIZER_TABLET_GP0610:
-	case USB_DEVICE_ID_UGEE_TABLET_EX07S:
-		/* If this is the pen interface */
-		if (intf->cur_altsetting->desc.bInterfaceNumber == 1) {
-			rc = uclogic_tablet_enable(hdev);
-			if (rc) {
-				hid_err(hdev, "tablet enabling failed\n");
-				return rc;
-			}
-			drvdata->invert_pen_inrange = true;
-		} else {
-			drvdata->ignore_pen_usage = true;
-		}
-		break;
-	case USB_DEVICE_ID_UCLOGIC_TABLET_TWHA60:
-		/*
-		 * If it is the three-interface version, which is known to
-		 * respond to initialization.
-		 */
-		if (udev->config->desc.bNumInterfaces == 3) {
-			/* If it is the pen interface */
-			if (intf->cur_altsetting->desc.bInterfaceNumber == 0) {
-				rc = uclogic_tablet_enable(hdev);
-				if (rc) {
-					hid_err(hdev, "tablet enabling failed\n");
-					return rc;
-				}
-				drvdata->invert_pen_inrange = true;
-
-				rc = uclogic_button_enable(hdev);
-				drvdata->has_virtual_pad_interface = !rc;
-			} else {
-				drvdata->ignore_pen_usage = true;
-			}
-		}
-		break;
-	}
-
-	rc = hid_parse(hdev);
-	if (rc) {
-		hid_err(hdev, "parse failed\n");
-		return rc;
-	}
-
-	rc = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
-	if (rc) {
-		hid_err(hdev, "hw start failed\n");
-		return rc;
-	}
-
-	return 0;
-}
-
-static int uclogic_raw_event(struct hid_device *hdev, struct hid_report *report,
-			u8 *data, int size)
-{
-	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
-
-	if ((report->type == HID_INPUT_REPORT) &&
-	    (report->id == UCLOGIC_PEN_REPORT_ID) &&
-	    (size >= 2)) {
-		if (drvdata->has_virtual_pad_interface && (data[1] & 0x20))
-			/* Change to virtual frame button report ID */
-			data[0] = 0xf7;
-		else if (drvdata->invert_pen_inrange)
-			/* Invert the in-range bit */
-			data[1] ^= 0x40;
-	}
-
-	return 0;
+	return rdesc_ptr;
 }
-
-static const struct hid_device_id uclogic_devices[] = {
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
-				USB_DEVICE_ID_UCLOGIC_TABLET_PF1209) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
-				USB_DEVICE_ID_UCLOGIC_TABLET_WP4030U) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
-				USB_DEVICE_ID_UCLOGIC_TABLET_WP5540U) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
-				USB_DEVICE_ID_UCLOGIC_TABLET_WP8060U) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
-				USB_DEVICE_ID_UCLOGIC_TABLET_WP1062) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
-				USB_DEVICE_ID_UCLOGIC_WIRELESS_TABLET_TWHL850) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC,
-				USB_DEVICE_ID_UCLOGIC_TABLET_TWHA60) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_HUION, USB_DEVICE_ID_HUION_TABLET) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_HUION_TABLET) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_YIYNOVA_TABLET) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UGEE_TABLET_81) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UGEE_TABLET_45) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UCLOGIC, USB_DEVICE_ID_UCLOGIC_DRAWIMAGE_G3) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UGTIZER, USB_DEVICE_ID_UGTIZER_TABLET_GP0610) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE, USB_DEVICE_ID_UGEE_TABLET_EX07S) },
-	{ }
-};
-MODULE_DEVICE_TABLE(hid, uclogic_devices);
-
-static struct hid_driver uclogic_driver = {
-	.name = "uclogic",
-	.id_table = uclogic_devices,
-	.probe = uclogic_probe,
-	.report_fixup = uclogic_report_fixup,
-	.raw_event = uclogic_raw_event,
-	.input_mapping = uclogic_input_mapping,
-	.input_configured = uclogic_input_configured,
-};
-module_hid_driver(uclogic_driver);
-
-MODULE_AUTHOR("Martin Rusko");
-MODULE_AUTHOR("Nikolai Kondrashov");
-MODULE_LICENSE("GPL");

drivers/hid/hid-uclogic-rdesc.h

+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ *  HID driver for UC-Logic devices not fully compliant with HID standard
+ *  - original and fixed report descriptors
+ *
+ *  Copyright (c) 2010-2018 Nikolai Kondrashov
+ *  Copyright (c) 2013 Martin Rusko
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#ifndef _HID_UCLOGIC_RDESC_H
+#define _HID_UCLOGIC_RDESC_H
+
+#include <linux/usb.h>
+
+/* Size of the original descriptor of WPXXXXU tablets */
+#define UCLOGIC_RDESC_WPXXXXU_ORIG_SIZE		212
+
+/* Fixed WP4030U report descriptor */
+extern __u8 uclogic_rdesc_wp4030u_fixed_arr[];
+extern const size_t uclogic_rdesc_wp4030u_fixed_size;
+
+/* Fixed WP5540U report descriptor */
+extern __u8 uclogic_rdesc_wp5540u_fixed_arr[];
+extern const size_t uclogic_rdesc_wp5540u_fixed_size;
+
+/* Fixed WP8060U report descriptor */
+extern __u8 uclogic_rdesc_wp8060u_fixed_arr[];
+extern const size_t uclogic_rdesc_wp8060u_fixed_size;
+
+/* Size of the original descriptor of the new WP5540U tablet */
+#define UCLOGIC_RDESC_WP5540U_V2_ORIG_SIZE	232
+
+/* Size of the original descriptor of WP1062 tablet */
+#define UCLOGIC_RDESC_WP1062_ORIG_SIZE		254
+
+/* Fixed WP1062 report descriptor */
+extern __u8 uclogic_rdesc_wp1062_fixed_arr[];
+extern const size_t uclogic_rdesc_wp1062_fixed_size;
+
+/* Size of the original descriptor of PF1209 tablet */
+#define UCLOGIC_RDESC_PF1209_ORIG_SIZE		234
+
+/* Fixed PF1209 report descriptor */
+extern __u8 uclogic_rdesc_pf1209_fixed_arr[];
+extern const size_t uclogic_rdesc_pf1209_fixed_size;
+
+/* Size of the original descriptors of TWHL850 tablet */
+#define UCLOGIC_RDESC_TWHL850_ORIG0_SIZE	182
+#define UCLOGIC_RDESC_TWHL850_ORIG1_SIZE	161
+#define UCLOGIC_RDESC_TWHL850_ORIG2_SIZE	92
+
+/* Fixed PID 0522 tablet report descriptor, interface 0 (stylus) */
+extern __u8 uclogic_rdesc_twhl850_fixed0_arr[];
+extern const size_t uclogic_rdesc_twhl850_fixed0_size;
+
+/* Fixed PID 0522 tablet report descriptor, interface 1 (mouse) */
+extern __u8 uclogic_rdesc_twhl850_fixed1_arr[];
+extern const size_t uclogic_rdesc_twhl850_fixed1_size;
+
+/* Fixed PID 0522 tablet report descriptor, interface 2 (frame buttons) */
+extern __u8 uclogic_rdesc_twhl850_fixed2_arr[];
+extern const size_t uclogic_rdesc_twhl850_fixed2_size;
+
+/* Size of the original descriptors of TWHA60 tablet */
+#define UCLOGIC_RDESC_TWHA60_ORIG0_SIZE		254
+#define UCLOGIC_RDESC_TWHA60_ORIG1_SIZE		139
+
+/* Fixed TWHA60 report descriptor, interface 0 (stylus) */
+extern __u8 uclogic_rdesc_twha60_fixed0_arr[];
+extern const size_t uclogic_rdesc_twha60_fixed0_size;
+
+/* Fixed TWHA60 report descriptor, interface 1 (frame buttons) */
+extern __u8 uclogic_rdesc_twha60_fixed1_arr[];
+extern const size_t uclogic_rdesc_twha60_fixed1_size;
+
+/* Report descriptor template placeholder head */
+#define UCLOGIC_RDESC_PH_HEAD	0xFE, 0xED, 0x1D
+
+/* Apply report descriptor parameters to a report descriptor template */
+extern __u8 *uclogic_rdesc_template_apply(const __u8 *template_ptr,
+					  size_t template_size,
+					  const s32 *param_list,
+					  size_t param_num);
+
+/* Pen report descriptor template placeholder IDs */
+enum uclogic_rdesc_pen_ph_id {
+	UCLOGIC_RDESC_PEN_PH_ID_X_LM,
+	UCLOGIC_RDESC_PEN_PH_ID_X_PM,
+	UCLOGIC_RDESC_PEN_PH_ID_Y_LM,
+	UCLOGIC_RDESC_PEN_PH_ID_Y_PM,
+	UCLOGIC_RDESC_PEN_PH_ID_PRESSURE_LM,
+	UCLOGIC_RDESC_PEN_PH_ID_NUM
+};
+
+/* Report descriptor pen template placeholder */
+#define UCLOGIC_RDESC_PEN_PH(_ID) \
+	UCLOGIC_RDESC_PH_HEAD, UCLOGIC_RDESC_PEN_PH_ID_##_ID
+
+/* Report ID for v1 pen reports */
+#define UCLOGIC_RDESC_PEN_V1_ID	0x07
+
+/* Fixed report descriptor template for (tweaked) v1 pen reports */
+extern const __u8 uclogic_rdesc_pen_v1_template_arr[];
+extern const size_t uclogic_rdesc_pen_v1_template_size;
+
+/* Report ID for v2 pen reports */
+#define UCLOGIC_RDESC_PEN_V2_ID	0x08
+
+/* Fixed report descriptor template for (tweaked) v2 pen reports */
+extern const __u8 uclogic_rdesc_pen_v2_template_arr[];
+extern const size_t uclogic_rdesc_pen_v2_template_size;
+
+/* Fixed report descriptor for (tweaked) v1 buttonpad reports */
+extern const __u8 uclogic_rdesc_buttonpad_v1_arr[];
+extern const size_t uclogic_rdesc_buttonpad_v1_size;
+
+/* Report ID for tweaked v1 buttonpad reports */
+#define UCLOGIC_RDESC_BUTTONPAD_V1_ID 0xf7
+
+/* Fixed report descriptor for (tweaked) v2 buttonpad reports */
+extern const __u8 uclogic_rdesc_buttonpad_v2_arr[];
+extern const size_t uclogic_rdesc_buttonpad_v2_size;
+
+/* Report ID for tweaked v2 buttonpad reports */
+#define UCLOGIC_RDESC_BUTTONPAD_V2_ID 0xf7
+
+/* Fixed report descriptor for Ugee EX07 buttonpad */
+extern const __u8 uclogic_rdesc_ugee_ex07_buttonpad_arr[];
+extern const size_t uclogic_rdesc_ugee_ex07_buttonpad_size;
+
+/* Fixed report descriptor for XP-Pen Deco 01 frame controls */
+extern const __u8 uclogic_rdesc_xppen_deco01_frame_arr[];
+extern const size_t uclogic_rdesc_xppen_deco01_frame_size;
+
+/* Fixed report descriptor for Ugee G5 frame controls */
+extern const __u8 uclogic_rdesc_ugee_g5_frame_arr[];
+extern const size_t uclogic_rdesc_ugee_g5_frame_size;
+
+/* Report ID of Ugee G5 frame control reports */
+#define UCLOGIC_RDESC_UGEE_G5_FRAME_ID 0x06
+
+/* Device ID byte offset in Ugee G5 frame report */
+#define UCLOGIC_RDESC_UGEE_G5_FRAME_DEV_ID_BYTE	0x2
+
+/* Least-significant bit of Ugee G5 frame rotary encoder state */
+#define UCLOGIC_RDESC_UGEE_G5_FRAME_RE_LSB 38
+
+#endif /* _HID_UCLOGIC_RDESC_H */

drivers/hid/hid-viewsonic.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  HID driver for ViewSonic devices not fully compliant with HID standard
+ *
+ *  Copyright (c) 2017 Nikolai Kondrashov
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+/* Size of the original descriptor of PD1011 signature pad */
+#define PD1011_RDESC_ORIG_SIZE	408
+
+/* Fixed report descriptor of PD1011 signature pad */
+static __u8 pd1011_rdesc_fixed[] = {
+	0x05, 0x0D,             /*  Usage Page (Digitizer),             */
+	0x09, 0x02,             /*  Usage (Pen),                        */
+	0xA1, 0x01,             /*  Collection (Application),           */
+	0x85, 0x02,             /*      Report ID (2),                  */
+	0x09, 0x20,             /*      Usage (Stylus),                 */
+	0xA0,                   /*      Collection (Physical),          */
+	0x75, 0x10,             /*          Report Size (16),           */
+	0x95, 0x01,             /*          Report Count (1),           */
+	0xA4,                   /*          Push,                       */
+	0x05, 0x01,             /*          Usage Page (Desktop),       */
+	0x65, 0x13,             /*          Unit (Inch),                */
+	0x55, 0xFD,             /*          Unit Exponent (-3),         */
+	0x34,                   /*          Physical Minimum (0),       */
+	0x09, 0x30,             /*          Usage (X),                  */
+	0x46, 0x5D, 0x21,       /*          Physical Maximum (8541),    */
+	0x27, 0x80, 0xA9,
+		0x00, 0x00,     /*          Logical Maximum (43392),    */
+	0x81, 0x02,             /*          Input (Variable),           */
+	0x09, 0x31,             /*          Usage (Y),                  */
+	0x46, 0xDA, 0x14,       /*          Physical Maximum (5338),    */
+	0x26, 0xF0, 0x69,       /*          Logical Maximum (27120),    */
+	0x81, 0x02,             /*          Input (Variable),           */
+	0xB4,                   /*          Pop,                        */
+	0x14,                   /*          Logical Minimum (0),        */
+	0x25, 0x01,             /*          Logical Maximum (1),        */
+	0x75, 0x01,             /*          Report Size (1),            */
+	0x95, 0x01,             /*          Report Count (1),           */
+	0x81, 0x03,             /*          Input (Constant, Variable), */
+	0x09, 0x32,             /*          Usage (In Range),           */
+	0x09, 0x42,             /*          Usage (Tip Switch),         */
+	0x95, 0x02,             /*          Report Count (2),           */
+	0x81, 0x02,             /*          Input (Variable),           */
+	0x95, 0x05,             /*          Report Count (5),           */
+	0x81, 0x03,             /*          Input (Constant, Variable), */
+	0x75, 0x10,             /*          Report Size (16),           */
+	0x95, 0x01,             /*          Report Count (1),           */
+	0x09, 0x30,             /*          Usage (Tip Pressure),       */
+	0x15, 0x05,             /*          Logical Minimum (5),        */
+	0x26, 0xFF, 0x07,       /*          Logical Maximum (2047),     */
+	0x81, 0x02,             /*          Input (Variable),           */
+	0x75, 0x10,             /*          Report Size (16),           */
+	0x95, 0x01,             /*          Report Count (1),           */
+	0x81, 0x03,             /*          Input (Constant, Variable), */
+	0xC0,                   /*      End Collection,                 */
+	0xC0                    /*  End Collection                      */
+};
+
+static __u8 *viewsonic_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+				    unsigned int *rsize)
+{
+	switch (hdev->product) {
+	case USB_DEVICE_ID_VIEWSONIC_PD1011:
+	case USB_DEVICE_ID_SIGNOTEC_VIEWSONIC_PD1011:
+		if (*rsize == PD1011_RDESC_ORIG_SIZE) {
+			rdesc = pd1011_rdesc_fixed;
+			*rsize = sizeof(pd1011_rdesc_fixed);
+		}
+		break;
+	}
+
+	return rdesc;
+}
+
+static const struct hid_device_id viewsonic_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_VIEWSONIC,
+				USB_DEVICE_ID_VIEWSONIC_PD1011) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SIGNOTEC,
+				USB_DEVICE_ID_SIGNOTEC_VIEWSONIC_PD1011) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, viewsonic_devices);
+
+static struct hid_driver viewsonic_driver = {
+	.name = "viewsonic",
+	.id_table = viewsonic_devices,
+	.report_fixup = viewsonic_report_fixup,
+};
+module_hid_driver(viewsonic_driver);
+
+MODULE_LICENSE("GPL");