Input: add Pegasus Notetaker tablet driver

This adds a driver for the Pegasus Notetaker Pen. When connected,
this uses the Pen as an input tablet.

This device was sold in various different brandings, for example
 "Pegasus Mobile Notetaker M210",
 "Genie e-note The Notetaker",
 "Staedtler Digital ballpoint pen 990 01",
 "IRISnotes Express" or
 "NEWLink Digital Note Taker".

Here's an example, so that you know what we are talking about:
http://www.genie-online.de/genie-e-note-2/

https://pegatech.blogspot.com/ seems to be a remaining official resource.

This device can also transfer saved (offline recorded handwritten) data and
there are userspace programs that do this, see https://launchpad.net/m210
(Well, alternatively there are really fast scanners out there :)

It's *really* fun to use as an input tablet though! So let's support this
for everybody.
Signed-off-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/tablet/Kconfig

@@ -73,6 +73,21 @@ config TABLET_USB_KBTAB
 	  To compile this driver as a module, choose M here: the
 	  module will be called kbtab.
 
+config TABLET_USB_PEGASUS
+	tristate "Pegasus Mobile Notetaker Pen input tablet support"
+	depends on USB_ARCH_HAS_HCD
+	select USB
+	help
+	  Say Y here if you want to use the Pegasus Mobile Notetaker,
+	  also known as:
+	  Genie e-note The Notetaker,
+	  Staedtler Digital ballpoint pen 990 01,
+	  IRISnotes Express or
+	  NEWLink Digital Note Taker.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called pegasus_notetaker.
+
 config TABLET_SERIAL_WACOM4
 	tristate "Wacom protocol 4 serial tablet support"
 	select SERIO

drivers/input/tablet/Makefile

@@ -8,4 +8,5 @@ obj-$(CONFIG_TABLET_USB_AIPTEK)	+= aiptek.o
 obj-$(CONFIG_TABLET_USB_GTCO)	+= gtco.o
 obj-$(CONFIG_TABLET_USB_HANWANG) += hanwang.o
 obj-$(CONFIG_TABLET_USB_KBTAB)	+= kbtab.o
+obj-$(CONFIG_TABLET_USB_PEGASUS) += pegasus_notetaker.o
 obj-$(CONFIG_TABLET_SERIAL_WACOM4) += wacom_serial4.o

drivers/input/tablet/pegasus_notetaker.c

+/*
+ * Pegasus Mobile Notetaker Pen input tablet driver
+ *
+ * Copyright (c) 2016 Martin Kepplinger <martink@posteo.de>
+ */
+
+/*
+ * request packet (control endpoint):
+ * |-------------------------------------|
+ * | Report ID | Nr of bytes | command   |
+ * | (1 byte)  | (1 byte)    | (n bytes) |
+ * |-------------------------------------|
+ * | 0x02      | n           |           |
+ * |-------------------------------------|
+ *
+ * data packet after set xy mode command, 0x80 0xb5 0x02 0x01
+ * and pen is in range:
+ *
+ * byte	byte name		value (bits)
+ * --------------------------------------------
+ * 0	status			0 1 0 0 0 0 X X
+ * 1	color			0 0 0 0 H 0 S T
+ * 2	X low
+ * 3	X high
+ * 4	Y low
+ * 5	Y high
+ *
+ * X X	battery state:
+ *	no state reported	0x00
+ *	battery low		0x01
+ *	battery good		0x02
+ *
+ * H	Hovering
+ * S	Switch 1 (pen button)
+ * T	Tip
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/usb/input.h>
+#include <linux/slab.h>
+
+/* USB HID defines */
+#define USB_REQ_GET_REPORT		0x01
+#define USB_REQ_SET_REPORT		0x09
+
+#define USB_VENDOR_ID_PEGASUSTECH	0x0e20
+#define USB_DEVICE_ID_PEGASUS_NOTETAKER_EN100	0x0101
+
+/* device specific defines */
+#define NOTETAKER_REPORT_ID		0x02
+#define NOTETAKER_SET_CMD		0x80
+#define NOTETAKER_SET_MODE		0xb5
+
+#define NOTETAKER_LED_MOUSE		0x02
+#define PEN_MODE_XY			0x01
+
+#define SPECIAL_COMMAND			0x80
+#define BUTTON_PRESSED			0xb5
+#define COMMAND_VERSION			0xa9
+
+/* in xy data packet */
+#define BATTERY_NO_REPORT		0x40
+#define BATTERY_LOW			0x41
+#define BATTERY_GOOD			0x42
+#define PEN_BUTTON_PRESSED		BIT(1)
+#define PEN_TIP				BIT(0)
+
+struct pegasus {
+	unsigned char *data;
+	u8 data_len;
+	dma_addr_t data_dma;
+	struct input_dev *dev;
+	struct usb_device *usbdev;
+	struct usb_interface *intf;
+	struct urb *irq;
+	char name[128];
+	char phys[64];
+	struct work_struct init;
+};
+
+static void pegasus_control_msg(struct pegasus *pegasus, u8 *data, int len)
+{
+	const int sizeof_buf = len + 2;
+	int result;
+	u8 *cmd_buf;
+
+	cmd_buf = kmalloc(sizeof_buf, GFP_KERNEL);
+	if (!cmd_buf)
+		return;
+
+	cmd_buf[0] = NOTETAKER_REPORT_ID;
+	cmd_buf[1] = len;
+	memcpy(cmd_buf + 2, data, len);
+
+	result = usb_control_msg(pegasus->usbdev,
+				 usb_sndctrlpipe(pegasus->usbdev, 0),
+				 USB_REQ_SET_REPORT,
+				 USB_TYPE_VENDOR | USB_DIR_OUT,
+				 0, 0, cmd_buf, sizeof_buf,
+				 USB_CTRL_SET_TIMEOUT);
+
+	if (result != sizeof_buf)
+		dev_err(&pegasus->usbdev->dev, "control msg error\n");
+
+	kfree(cmd_buf);
+}
+
+static void pegasus_set_mode(struct pegasus *pegasus, u8 mode, u8 led)
+{
+	u8 cmd[] = { NOTETAKER_SET_CMD, NOTETAKER_SET_MODE, led, mode };
+
+	pegasus_control_msg(pegasus, cmd, sizeof(cmd));
+}
+
+static void pegasus_parse_packet(struct pegasus *pegasus)
+{
+	unsigned char *data = pegasus->data;
+	struct input_dev *dev = pegasus->dev;
+	u16 x, y;
+
+	switch (data[0]) {
+	case SPECIAL_COMMAND:
+		/* device button pressed */
+		if (data[1] == BUTTON_PRESSED)
+			schedule_work(&pegasus->init);
+
+		break;
+
+	/* xy data */
+	case BATTERY_LOW:
+		dev_warn_once(&dev->dev, "Pen battery low\n");
+		/* fall through */
+
+	case BATTERY_NO_REPORT:
+	case BATTERY_GOOD:
+		x = le16_to_cpup((__le16 *)&data[2]);
+		y = le16_to_cpup((__le16 *)&data[4]);
+
+		/* pen-up event */
+		if (x == 0 && y == 0)
+			break;
+
+		input_report_key(dev, BTN_TOUCH, data[1] & PEN_TIP);
+		input_report_key(dev, BTN_RIGHT, data[1] & PEN_BUTTON_PRESSED);
+		input_report_key(dev, BTN_TOOL_PEN, 1);
+		input_report_abs(dev, ABS_X, (s16)x);
+		input_report_abs(dev, ABS_Y, y);
+
+		input_sync(dev);
+		break;
+
+	default:
+		dev_warn_once(&pegasus->usbdev->dev,
+			      "unknown answer from device\n");
+	}
+}
+
+static void pegasus_irq(struct urb *urb)
+{
+	struct pegasus *pegasus = urb->context;
+	struct usb_device *dev = pegasus->usbdev;
+	int retval;
+
+	switch (urb->status) {
+	case 0:
+		pegasus_parse_packet(pegasus);
+		usb_mark_last_busy(pegasus->usbdev);
+		break;
+
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		dev_err(&dev->dev, "%s - urb shutting down with status: %d",
+			__func__, urb->status);
+		return;
+
+	default:
+		dev_err(&dev->dev, "%s - nonzero urb status received: %d",
+			__func__, urb->status);
+		break;
+	}
+
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval)
+		dev_err(&dev->dev, "%s - usb_submit_urb failed with result %d",
+			__func__, retval);
+}
+
+static void pegasus_init(struct work_struct *work)
+{
+	struct pegasus *pegasus = container_of(work, struct pegasus, init);
+
+	pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
+}
+
+static int pegasus_open(struct input_dev *dev)
+{
+	struct pegasus *pegasus = input_get_drvdata(dev);
+	int retval;
+
+	retval = usb_autopm_get_interface(pegasus->intf);
+	if (retval)
+		return retval;
+
+	pegasus->irq->dev = pegasus->usbdev;
+	if (usb_submit_urb(pegasus->irq, GFP_KERNEL))
+		retval = -EIO;
+
+	pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
+
+	usb_autopm_put_interface(pegasus->intf);
+
+	return retval;
+}
+
+static void pegasus_close(struct input_dev *dev)
+{
+	struct pegasus *pegasus = input_get_drvdata(dev);
+	int autopm_error;
+
+	autopm_error = usb_autopm_get_interface(pegasus->intf);
+	usb_kill_urb(pegasus->irq);
+	cancel_work_sync(&pegasus->init);
+
+	if (!autopm_error)
+		usb_autopm_put_interface(pegasus->intf);
+}
+
+static int pegasus_probe(struct usb_interface *intf,
+			 const struct usb_device_id *id)
+{
+	struct usb_device *dev = interface_to_usbdev(intf);
+	struct usb_endpoint_descriptor *endpoint;
+	struct pegasus *pegasus;
+	struct input_dev *input_dev;
+	int error;
+	int pipe;
+
+	/* We control interface 0 */
+	if (intf->cur_altsetting->desc.bInterfaceNumber >= 1)
+		return -ENODEV;
+
+	/* Sanity check that the device has an endpoint */
+	if (intf->altsetting[0].desc.bNumEndpoints < 1) {
+		dev_err(&intf->dev, "Invalid number of endpoints\n");
+		return -EINVAL;
+	}
+
+	endpoint = &intf->cur_altsetting->endpoint[0].desc;
+
+	pegasus = kzalloc(sizeof(*pegasus), GFP_KERNEL);
+	input_dev = input_allocate_device();
+	if (!pegasus || !input_dev) {
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	pegasus->usbdev = dev;
+	pegasus->dev = input_dev;
+	pegasus->intf = intf;
+
+	pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);
+	pegasus->data_len = usb_maxpacket(dev, pipe, usb_pipeout(pipe));
+
+	pegasus->data = usb_alloc_coherent(dev, pegasus->data_len, GFP_KERNEL,
+					   &pegasus->data_dma);
+	if (!pegasus->data) {
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	pegasus->irq = usb_alloc_urb(0, GFP_KERNEL);
+	if (!pegasus->irq) {
+		error = -ENOMEM;
+		goto err_free_dma;
+	}
+
+	usb_fill_int_urb(pegasus->irq, dev, pipe,
+			 pegasus->data, pegasus->data_len,
+			 pegasus_irq, pegasus, endpoint->bInterval);
+
+	pegasus->irq->transfer_dma = pegasus->data_dma;
+	pegasus->irq->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+	if (dev->manufacturer)
+		strlcpy(pegasus->name, dev->manufacturer,
+			sizeof(pegasus->name));
+
+	if (dev->product) {
+		if (dev->manufacturer)
+			strlcat(pegasus->name, " ", sizeof(pegasus->name));
+		strlcat(pegasus->name, dev->product, sizeof(pegasus->name));
+	}
+
+	if (!strlen(pegasus->name))
+		snprintf(pegasus->name, sizeof(pegasus->name),
+			 "USB Pegasus Device %04x:%04x",
+			 le16_to_cpu(dev->descriptor.idVendor),
+			 le16_to_cpu(dev->descriptor.idProduct));
+
+	usb_make_path(dev, pegasus->phys, sizeof(pegasus->phys));
+	strlcat(pegasus->phys, "/input0", sizeof(pegasus->phys));
+
+	INIT_WORK(&pegasus->init, pegasus_init);
+
+	usb_set_intfdata(intf, pegasus);
+
+	input_dev->name = pegasus->name;
+	input_dev->phys = pegasus->phys;
+	usb_to_input_id(dev, &input_dev->id);
+	input_dev->dev.parent = &intf->dev;
+
+	input_set_drvdata(input_dev, pegasus);
+
+	input_dev->open = pegasus_open;
+	input_dev->close = pegasus_close;
+
+	__set_bit(EV_ABS, input_dev->evbit);
+	__set_bit(EV_KEY, input_dev->evbit);
+
+	__set_bit(ABS_X, input_dev->absbit);
+	__set_bit(ABS_Y, input_dev->absbit);
+
+	__set_bit(BTN_TOUCH, input_dev->keybit);
+	__set_bit(BTN_RIGHT, input_dev->keybit);
+	__set_bit(BTN_TOOL_PEN, input_dev->keybit);
+
+	__set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
+	__set_bit(INPUT_PROP_POINTER, input_dev->propbit);
+
+	input_set_abs_params(input_dev, ABS_X, -1500, 1500, 8, 0);
+	input_set_abs_params(input_dev, ABS_Y, 1600, 3000, 8, 0);
+
+	error = input_register_device(pegasus->dev);
+	if (error)
+		goto err_free_urb;
+
+	return 0;
+
+err_free_urb:
+	usb_free_urb(pegasus->irq);
+err_free_dma:
+	usb_free_coherent(dev, pegasus->data_len,
+			  pegasus->data, pegasus->data_dma);
+err_free_mem:
+	input_free_device(input_dev);
+	kfree(pegasus);
+	usb_set_intfdata(intf, NULL);
+
+	return error;
+}
+
+static void pegasus_disconnect(struct usb_interface *intf)
+{
+	struct pegasus *pegasus = usb_get_intfdata(intf);
+
+	input_unregister_device(pegasus->dev);
+
+	usb_free_urb(pegasus->irq);
+	usb_free_coherent(interface_to_usbdev(intf),
+			  pegasus->data_len, pegasus->data,
+			  pegasus->data_dma);
+
+	kfree(pegasus);
+	usb_set_intfdata(intf, NULL);
+}
+
+static int pegasus_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct pegasus *pegasus = usb_get_intfdata(intf);
+
+	mutex_lock(&pegasus->dev->mutex);
+	usb_kill_urb(pegasus->irq);
+	mutex_unlock(&pegasus->dev->mutex);
+
+	return 0;
+}
+
+static int pegasus_resume(struct usb_interface *intf)
+{
+	struct pegasus *pegasus = usb_get_intfdata(intf);
+	int retval = 0;
+
+	mutex_lock(&pegasus->dev->mutex);
+	if (pegasus->dev->users && usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
+		retval = -EIO;
+	mutex_unlock(&pegasus->dev->mutex);
+
+	return retval;
+}
+
+static int pegasus_reset_resume(struct usb_interface *intf)
+{
+	return pegasus_resume(intf);
+}
+
+static const struct usb_device_id pegasus_ids[] = {
+	{ USB_DEVICE(USB_VENDOR_ID_PEGASUSTECH,
+		     USB_DEVICE_ID_PEGASUS_NOTETAKER_EN100) },
+	{ }
+};
+MODULE_DEVICE_TABLE(usb, pegasus_ids);
+
+static struct usb_driver pegasus_driver = {
+	.name		= "pegasus_notetaker",
+	.probe		= pegasus_probe,
+	.disconnect	= pegasus_disconnect,
+	.suspend	= pegasus_suspend,
+	.resume		= pegasus_resume,
+	.reset_resume	= pegasus_reset_resume,
+	.id_table	= pegasus_ids,
+	.supports_autosuspend = 1,
+};
+
+module_usb_driver(pegasus_driver);
+
+MODULE_AUTHOR("Martin Kepplinger <martink@posteo.de>");
+MODULE_DESCRIPTION("Pegasus Mobile Notetaker Pen tablet driver");
+MODULE_LICENSE("GPL");