HID: Add driver for Logitech gaming keyboards (G15, G15 v2)

Add a driver to stop the extra "G" keys from sending F1 - F12 instead
making them send KEY_GKEY# and also make the non-functional M1 - M3 and MR
keys and the non-functional buttons below the LCD panel properly generated
key events.

Note the connect_mask and gkeys_settings_output_report variables may seem
unnecessary since they are always set to the same value, these are there in
preparation of adding support for the G, M and LCD keys on the G510 kbd.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

MAINTAINERS

@@ -9587,6 +9587,13 @@ S:	Maintained
 F:	Documentation/admin-guide/ldm.rst
 F:	block/partitions/ldm.*
 
+LOGITECH HID GAMING KEYBOARDS
+M:	Hans de Goede <hdegoede@redhat.com>
+L:	linux-input@vger.kernel.org
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git
+S:	Maintained
+F:	drivers/hid/hid-lg-g15.c
+
 LSILOGIC MPT FUSION DRIVERS (FC/SAS/SPI)
 M:	Sathya Prakash <sathya.prakash@broadcom.com>
 M:	Chaitra P B <chaitra.basappa@broadcom.com>

drivers/hid/Makefile

@@ -64,6 +64,7 @@ obj-$(CONFIG_HID_KYE)		+= hid-kye.o
 obj-$(CONFIG_HID_LCPOWER)	+= hid-lcpower.o
 obj-$(CONFIG_HID_LENOVO)	+= hid-lenovo.o
 obj-$(CONFIG_HID_LOGITECH)	+= hid-logitech.o
+obj-$(CONFIG_HID_LOGITECH)	+= hid-lg-g15.o
 obj-$(CONFIG_HID_LOGITECH_DJ)	+= hid-logitech-dj.o
 obj-$(CONFIG_HID_LOGITECH_HIDPP)	+= hid-logitech-hidpp.o
 obj-$(CONFIG_HID_MACALLY)	+= hid-macally.o

drivers/hid/hid-ids.h

@@ -747,6 +747,8 @@
 #define USB_DEVICE_ID_LOGITECH_DUAL_ACTION	0xc216
 #define USB_DEVICE_ID_LOGITECH_RUMBLEPAD2	0xc218
 #define USB_DEVICE_ID_LOGITECH_RUMBLEPAD2_2	0xc219
+#define USB_DEVICE_ID_LOGITECH_G15_LCD		0xc222
+#define USB_DEVICE_ID_LOGITECH_G15_V2_LCD	0xc227
 #define USB_DEVICE_ID_LOGITECH_G29_WHEEL	0xc24f
 #define USB_DEVICE_ID_LOGITECH_G920_WHEEL	0xc262
 #define USB_DEVICE_ID_LOGITECH_WINGMAN_F3D	0xc283

drivers/hid/hid-lg-g15.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  HID driver for gaming keys on Logitech gaming keyboards (such as the G15)
+ *
+ *  Copyright (c) 2019 Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <linux/usb.h>
+#include <linux/wait.h>
+
+#include "hid-ids.h"
+
+#define LG_G15_TRANSFER_BUF_SIZE	20
+
+enum lg_g15_model {
+	LG_G15,
+	LG_G15_V2,
+};
+
+struct lg_g15_data {
+	/* Must be first for proper dma alignment */
+	u8 transfer_buf[LG_G15_TRANSFER_BUF_SIZE];
+	struct input_dev *input;
+	struct hid_device *hdev;
+	enum lg_g15_model model;
+};
+
+/* On the G15 Mark I Logitech has been quite creative with which bit is what */
+static int lg_g15_event(struct lg_g15_data *g15, u8 *data, int size)
+{
+	int i, val;
+
+	/* G1 - G6 */
+	for (i = 0; i < 6; i++) {
+		val = data[i + 1] & (1 << i);
+		input_report_key(g15->input, KEY_MACRO1 + i, val);
+	}
+	/* G7 - G12 */
+	for (i = 0; i < 6; i++) {
+		val = data[i + 2] & (1 << i);
+		input_report_key(g15->input, KEY_MACRO7 + i, val);
+	}
+	/* G13 - G17 */
+	for (i = 0; i < 5; i++) {
+		val = data[i + 1] & (4 << i);
+		input_report_key(g15->input, KEY_MACRO13 + i, val);
+	}
+	/* G18 */
+	input_report_key(g15->input, KEY_MACRO18, data[8] & 0x40);
+
+	/* M1 - M3 */
+	for (i = 0; i < 3; i++) {
+		val = data[i + 6] & (1 << i);
+		input_report_key(g15->input, KEY_MACRO_PRESET1 + i, val);
+	}
+	/* MR */
+	input_report_key(g15->input, KEY_MACRO_RECORD_START, data[7] & 0x40);
+
+	/* Most left (round) button below the LCD */
+	input_report_key(g15->input, KEY_KBD_LCD_MENU1, data[8] & 0x80);
+	/* 4 other buttons below the LCD */
+	for (i = 0; i < 4; i++) {
+		val = data[i + 2] & 0x80;
+		input_report_key(g15->input, KEY_KBD_LCD_MENU2 + i, val);
+	}
+
+	input_sync(g15->input);
+	return 0;
+}
+
+static int lg_g15_v2_event(struct lg_g15_data *g15, u8 *data, int size)
+{
+	int i, val;
+
+	/* G1 - G6 */
+	for (i = 0; i < 6; i++) {
+		val = data[1] & (1 << i);
+		input_report_key(g15->input, KEY_MACRO1 + i, val);
+	}
+
+	/* M1 - M3 + MR */
+	input_report_key(g15->input, KEY_MACRO_PRESET1, data[1] & 0x40);
+	input_report_key(g15->input, KEY_MACRO_PRESET2, data[1] & 0x80);
+	input_report_key(g15->input, KEY_MACRO_PRESET3, data[2] & 0x20);
+	input_report_key(g15->input, KEY_MACRO_RECORD_START, data[2] & 0x40);
+
+	/* Round button to the left of the LCD */
+	input_report_key(g15->input, KEY_KBD_LCD_MENU1, data[2] & 0x80);
+	/* 4 buttons below the LCD */
+	for (i = 0; i < 4; i++) {
+		val = data[2] & (2 << i);
+		input_report_key(g15->input, KEY_KBD_LCD_MENU2 + i, val);
+	}
+
+	input_sync(g15->input);
+	return 0;
+}
+
+static int lg_g15_raw_event(struct hid_device *hdev, struct hid_report *report,
+			    u8 *data, int size)
+{
+	struct lg_g15_data *g15 = hid_get_drvdata(hdev);
+
+	if (g15->model == LG_G15 && data[0] == 0x02 && size == 9)
+		return lg_g15_event(g15, data, size);
+
+	if (g15->model == LG_G15_V2 && data[0] == 0x02 && size == 5)
+		return lg_g15_v2_event(g15, data, size);
+
+	return 0;
+}
+
+static int lg_g15_input_open(struct input_dev *dev)
+{
+	struct hid_device *hdev = input_get_drvdata(dev);
+
+	return hid_hw_open(hdev);
+}
+
+static void lg_g15_input_close(struct input_dev *dev)
+{
+	struct hid_device *hdev = input_get_drvdata(dev);
+
+	hid_hw_close(hdev);
+}
+
+static int lg_g15_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	u8 gkeys_settings_output_report = 0;
+	unsigned int connect_mask = 0;
+	struct lg_g15_data *g15;
+	struct input_dev *input;
+	int ret, i, gkeys = 0;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	g15 = devm_kzalloc(&hdev->dev, sizeof(*g15), GFP_KERNEL);
+	if (!g15)
+		return -ENOMEM;
+
+	input = devm_input_allocate_device(&hdev->dev);
+	if (!input)
+		return -ENOMEM;
+
+	g15->hdev = hdev;
+	g15->model = id->driver_data;
+	hid_set_drvdata(hdev, (void *)g15);
+
+	switch (g15->model) {
+	case LG_G15:
+		/*
+		 * The G15 and G15 v2 use a separate usb-device (on a builtin
+		 * hub) which emulates a keyboard for the F1 - F12 emulation
+		 * on the G-keys, which we disable, rendering the emulated kbd
+		 * non-functional, so we do not let hid-input connect.
+		 */
+		connect_mask = HID_CONNECT_HIDRAW;
+		gkeys_settings_output_report = 0x02;
+		gkeys = 18;
+		break;
+	case LG_G15_V2:
+		connect_mask = HID_CONNECT_HIDRAW;
+		gkeys_settings_output_report = 0x02;
+		gkeys = 6;
+		break;
+	}
+
+	ret = hid_hw_start(hdev, connect_mask);
+	if (ret)
+		return ret;
+
+	/* Tell the keyboard to stop sending F1-F12 + 1-6 for G1 - G18 */
+	if (gkeys_settings_output_report) {
+		g15->transfer_buf[0] = gkeys_settings_output_report;
+		memset(g15->transfer_buf + 1, 0, gkeys);
+		/*
+		 * The kbd ignores our output report if we do not queue
+		 * an URB on the USB input endpoint first...
+		 */
+		ret = hid_hw_open(hdev);
+		if (ret)
+			goto error_hw_stop;
+		ret = hid_hw_output_report(hdev, g15->transfer_buf, gkeys + 1);
+		hid_hw_close(hdev);
+	}
+
+	if (ret < 0) {
+		hid_err(hdev, "Error disabling keyboard emulation for the G-keys\n");
+		goto error_hw_stop;
+	}
+
+	input->name = "Logitech Gaming Keyboard Gaming Keys";
+	input->phys = hdev->phys;
+	input->uniq = hdev->uniq;
+	input->id.bustype = hdev->bus;
+	input->id.vendor  = hdev->vendor;
+	input->id.product = hdev->product;
+	input->id.version = hdev->version;
+	input->dev.parent = &hdev->dev;
+	input->open = lg_g15_input_open;
+	input->close = lg_g15_input_close;
+
+	/* G-keys */
+	for (i = 0; i < gkeys; i++)
+		input_set_capability(input, EV_KEY, KEY_MACRO1 + i);
+
+	/* M1 - M3 and MR keys */
+	for (i = 0; i < 3; i++)
+		input_set_capability(input, EV_KEY, KEY_MACRO_PRESET1 + i);
+	input_set_capability(input, EV_KEY, KEY_MACRO_RECORD_START);
+
+	/* Keys below the LCD, intended for controlling a menu on the LCD */
+	for (i = 0; i < 5; i++)
+		input_set_capability(input, EV_KEY, KEY_KBD_LCD_MENU1 + i);
+
+	g15->input = input;
+	input_set_drvdata(input, hdev);
+
+	ret = input_register_device(input);
+	if (ret)
+		goto error_hw_stop;
+
+	return 0;
+
+error_hw_stop:
+	hid_hw_stop(hdev);
+	return ret;
+}
+
+static const struct hid_device_id lg_g15_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
+			 USB_DEVICE_ID_LOGITECH_G15_LCD),
+		.driver_data = LG_G15 },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
+			 USB_DEVICE_ID_LOGITECH_G15_V2_LCD),
+		.driver_data = LG_G15_V2 },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, lg_g15_devices);
+
+static struct hid_driver lg_g15_driver = {
+	.name			= "lg-g15",
+	.id_table		= lg_g15_devices,
+	.raw_event		= lg_g15_raw_event,
+	.probe			= lg_g15_probe,
+};
+module_hid_driver(lg_g15_driver);
+
+MODULE_LICENSE("GPL");