drivers/input/touchscreen/wacom_w8001.c - pub/scm/linux/kernel/git/kbingham/rcar - Git at Google

 /*
  * Wacom W8001 penabled serial touchscreen driver
  *
  * Copyright (c) 2008 Jaya Kumar
  * Copyright (c) 2010 Red Hat, Inc.
  * Copyright (c) 2010 - 2011 Ping Cheng, Wacom. <pingc@wacom.com>
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License. See the file COPYING in the main directory of this archive for
  * more details.
  *
  * Layout based on Elo serial touchscreen driver by Vojtech Pavlik
  */

 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/input/mt.h>
 #include <linux/serio.h>
 #include <linux/ctype.h>
 #include <linux/delay.h>

 #define DRIVER_DESC	"Wacom W8001 serial touchscreen driver"

 MODULE_AUTHOR("Jaya Kumar <jayakumar.lkml@gmail.com>");
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");

 #define W8001_MAX_LENGTH	13
 #define W8001_LEAD_MASK		0x80
 #define W8001_LEAD_BYTE		0x80
 #define W8001_TAB_MASK		0x40
 #define W8001_TAB_BYTE		0x40
 /* set in first byte of touch data packets */
 #define W8001_TOUCH_MASK	(0x10 | W8001_LEAD_MASK)
 #define W8001_TOUCH_BYTE	(0x10 | W8001_LEAD_BYTE)

 #define W8001_QUERY_PACKET	0x20

 #define W8001_CMD_STOP		'0'
 #define W8001_CMD_START		'1'
 #define W8001_CMD_QUERY		'*'
 #define W8001_CMD_TOUCHQUERY	'%'

 /* length of data packets in bytes, depends on device. */
 #define W8001_PKTLEN_TOUCH93	5
 #define W8001_PKTLEN_TOUCH9A	7
 #define W8001_PKTLEN_TPCPEN	9
 #define W8001_PKTLEN_TPCCTL	11	/* control packet */
 #define W8001_PKTLEN_TOUCH2FG	13

 /* resolution in points/mm */
 #define W8001_PEN_RESOLUTION    100
 #define W8001_TOUCH_RESOLUTION  10

 struct w8001_coord {
 	u8 rdy;
 	u8 tsw;
 	u8 f1;
 	u8 f2;
 	u16 x;
 	u16 y;
 	u16 pen_pressure;
 	u8 tilt_x;
 	u8 tilt_y;
 };

 /* touch query reply packet */
 struct w8001_touch_query {
 	u16 x;
 	u16 y;
 	u8 panel_res;
 	u8 capacity_res;
 	u8 sensor_id;
 };

 /*
  * Per-touchscreen data.
  */

 struct w8001 {
 	struct input_dev *pen_dev;
 	struct input_dev *touch_dev;
 	struct serio *serio;
 	struct completion cmd_done;
 	int id;
 	int idx;
 	unsigned char response_type;
 	unsigned char response[W8001_MAX_LENGTH];
 	unsigned char data[W8001_MAX_LENGTH];
 	char phys[32];
 	int type;
 	unsigned int pktlen;
 	u16 max_touch_x;
 	u16 max_touch_y;
 	u16 max_pen_x;
 	u16 max_pen_y;
 	char pen_name[64];
 	char touch_name[64];
 	int open_count;
 	struct mutex mutex;
 };

 static void parse_pen_data(u8 *data, struct w8001_coord *coord)
 {
 	memset(coord, 0, sizeof(*coord));

 	coord->rdy = data[0] & 0x20;
 	coord->tsw = data[0] & 0x01;
 	coord->f1 = data[0] & 0x02;
 	coord->f2 = data[0] & 0x04;

 	coord->x = (data[1] & 0x7F) << 9;
 	coord->x |= (data[2] & 0x7F) << 2;
 	coord->x |= (data[6] & 0x60) >> 5;

 	coord->y = (data[3] & 0x7F) << 9;
 	coord->y |= (data[4] & 0x7F) << 2;
 	coord->y |= (data[6] & 0x18) >> 3;

 	coord->pen_pressure = data[5] & 0x7F;
 	coord->pen_pressure |= (data[6] & 0x07) << 7 ;

 	coord->tilt_x = data[7] & 0x7F;
 	coord->tilt_y = data[8] & 0x7F;
 }

 static void parse_single_touch(u8 *data, struct w8001_coord *coord)
 {
 	coord->x = (data[1] << 7) | data[2];
 	coord->y = (data[3] << 7) | data[4];
 	coord->tsw = data[0] & 0x01;
 }

 static void scale_touch_coordinates(struct w8001 *w8001,
 				    unsigned int *x, unsigned int *y)
 {
 	if (w8001->max_pen_x && w8001->max_touch_x)
 		*x = *x * w8001->max_pen_x / w8001->max_touch_x;

 	if (w8001->max_pen_y && w8001->max_touch_y)
 		*y = *y * w8001->max_pen_y / w8001->max_touch_y;
 }

 static void parse_multi_touch(struct w8001 *w8001)
 {
 	struct input_dev *dev = w8001->touch_dev;
 	unsigned char *data = w8001->data;
 	unsigned int x, y;
 	int i;
 	int count = 0;

 	for (i = 0; i < 2; i++) {
 		bool touch = data[0] & (1 << i);

 		input_mt_slot(dev, i);
 		input_mt_report_slot_state(dev, MT_TOOL_FINGER, touch);
 		if (touch) {
 			x = (data[6 * i + 1] << 7) | data[6 * i + 2];
 			y = (data[6 * i + 3] << 7) | data[6 * i + 4];
 			/* data[5,6] and [11,12] is finger capacity */

 			/* scale to pen maximum */
 			scale_touch_coordinates(w8001, &x, &y);

 			input_report_abs(dev, ABS_MT_POSITION_X, x);
 			input_report_abs(dev, ABS_MT_POSITION_Y, y);
 			count++;
 		}
 	}

 	/* emulate single touch events when stylus is out of proximity.
 	 * This is to make single touch backward support consistent
 	 * across all Wacom single touch devices.
 	 */
 	if (w8001->type != BTN_TOOL_PEN &&
 			    w8001->type != BTN_TOOL_RUBBER) {
 		w8001->type = count == 1 ? BTN_TOOL_FINGER : KEY_RESERVED;
 		input_mt_report_pointer_emulation(dev, true);
 	}

 	input_sync(dev);
 }

 static void parse_touchquery(u8 *data, struct w8001_touch_query *query)
 {
 	memset(query, 0, sizeof(*query));

 	query->panel_res = data[1];
 	query->sensor_id = data[2] & 0x7;
 	query->capacity_res = data[7];

 	query->x = data[3] << 9;
 	query->x |= data[4] << 2;
 	query->x |= (data[2] >> 5) & 0x3;

 	query->y = data[5] << 9;
 	query->y |= data[6] << 2;
 	query->y |= (data[2] >> 3) & 0x3;

 	/* Early days' single-finger touch models need the following defaults */
 	if (!query->x && !query->y) {
 		query->x = 1024;
 		query->y = 1024;
 		if (query->panel_res)
 			query->x = query->y = (1 << query->panel_res);
 		query->panel_res = W8001_TOUCH_RESOLUTION;
 	}
 }

 static void report_pen_events(struct w8001 *w8001, struct w8001_coord *coord)
 {
 	struct input_dev *dev = w8001->pen_dev;

 	/*
 	 * We have 1 bit for proximity (rdy) and 3 bits for tip, side,
 	 * side2/eraser. If rdy && f2 are set, this can be either pen + side2,
 	 * or eraser. Assume:
 	 * - if dev is already in proximity and f2 is toggled → pen + side2
 	 * - if dev comes into proximity with f2 set → eraser
 	 * If f2 disappears after assuming eraser, fake proximity out for
 	 * eraser and in for pen.
 	 */

 	switch (w8001->type) {
 	case BTN_TOOL_RUBBER:
 		if (!coord->f2) {
 			input_report_abs(dev, ABS_PRESSURE, 0);
 			input_report_key(dev, BTN_TOUCH, 0);
 			input_report_key(dev, BTN_STYLUS, 0);
 			input_report_key(dev, BTN_STYLUS2, 0);
 			input_report_key(dev, BTN_TOOL_RUBBER, 0);
 			input_sync(dev);
 			w8001->type = BTN_TOOL_PEN;
 		}
 		break;

 	case BTN_TOOL_FINGER:
 	case KEY_RESERVED:
 		w8001->type = coord->f2 ? BTN_TOOL_RUBBER : BTN_TOOL_PEN;
 		break;

 	default:
 		input_report_key(dev, BTN_STYLUS2, coord->f2);
 		break;
 	}

 	input_report_abs(dev, ABS_X, coord->x);
 	input_report_abs(dev, ABS_Y, coord->y);
 	input_report_abs(dev, ABS_PRESSURE, coord->pen_pressure);
 	input_report_key(dev, BTN_TOUCH, coord->tsw);
 	input_report_key(dev, BTN_STYLUS, coord->f1);
 	input_report_key(dev, w8001->type, coord->rdy);
 	input_sync(dev);

 	if (!coord->rdy)
 		w8001->type = KEY_RESERVED;
 }

 static void report_single_touch(struct w8001 *w8001, struct w8001_coord *coord)
 {
 	struct input_dev *dev = w8001->touch_dev;
 	unsigned int x = coord->x;
 	unsigned int y = coord->y;

 	/* scale to pen maximum */
 	scale_touch_coordinates(w8001, &x, &y);

 	input_report_abs(dev, ABS_X, x);
 	input_report_abs(dev, ABS_Y, y);
 	input_report_key(dev, BTN_TOUCH, coord->tsw);

 	input_sync(dev);

 	w8001->type = coord->tsw ? BTN_TOOL_FINGER : KEY_RESERVED;
 }

 static irqreturn_t w8001_interrupt(struct serio *serio,
 				   unsigned char data, unsigned int flags)
 {
 	struct w8001 *w8001 = serio_get_drvdata(serio);
 	struct w8001_coord coord;
 	unsigned char tmp;

 	w8001->data[w8001->idx] = data;
 	switch (w8001->idx++) {
 	case 0:
 		if ((data & W8001_LEAD_MASK) != W8001_LEAD_BYTE) {
 			pr_debug("w8001: unsynchronized data: 0x%02x\n", data);
 			w8001->idx = 0;
 		}
 		break;

 	case W8001_PKTLEN_TOUCH93 - 1:
 	case W8001_PKTLEN_TOUCH9A - 1:
 		tmp = w8001->data[0] & W8001_TOUCH_BYTE;
 		if (tmp != W8001_TOUCH_BYTE)
 			break;

 		if (w8001->pktlen == w8001->idx) {
 			w8001->idx = 0;
 			if (w8001->type != BTN_TOOL_PEN &&
 			    w8001->type != BTN_TOOL_RUBBER) {
 				parse_single_touch(w8001->data, &coord);
 				report_single_touch(w8001, &coord);
 			}
 		}
 		break;

 	/* Pen coordinates packet */
 	case W8001_PKTLEN_TPCPEN - 1:
 		tmp = w8001->data[0] & W8001_TAB_MASK;
 		if (unlikely(tmp == W8001_TAB_BYTE))
 			break;

 		tmp = w8001->data[0] & W8001_TOUCH_BYTE;
 		if (tmp == W8001_TOUCH_BYTE)
 			break;

 		w8001->idx = 0;
 		parse_pen_data(w8001->data, &coord);
 		report_pen_events(w8001, &coord);
 		break;

 	/* control packet */
 	case W8001_PKTLEN_TPCCTL - 1:
 		tmp = w8001->data[0] & W8001_TOUCH_MASK;
 		if (tmp == W8001_TOUCH_BYTE)
 			break;

 		w8001->idx = 0;
 		memcpy(w8001->response, w8001->data, W8001_MAX_LENGTH);
 		w8001->response_type = W8001_QUERY_PACKET;
 		complete(&w8001->cmd_done);
 		break;

 	/* 2 finger touch packet */
 	case W8001_PKTLEN_TOUCH2FG - 1:
 		w8001->idx = 0;
 		parse_multi_touch(w8001);
 		break;

 	default:
 		/*
 		 * ThinkPad X60 Tablet PC (pen only device) sometimes
 		 * sends invalid data packets that are larger than
 		 * W8001_PKTLEN_TPCPEN. Let's start over again.
 		 */
 		if (!w8001->touch_dev && w8001->idx > W8001_PKTLEN_TPCPEN - 1)
 			w8001->idx = 0;
 	}

 	return IRQ_HANDLED;
 }

 static int w8001_command(struct w8001 *w8001, unsigned char command,
 			 bool wait_response)
 {
 	int rc;

 	w8001->response_type = 0;
 	init_completion(&w8001->cmd_done);

 	rc = serio_write(w8001->serio, command);
 	if (rc == 0 && wait_response) {

 		wait_for_completion_timeout(&w8001->cmd_done, HZ);
 		if (w8001->response_type != W8001_QUERY_PACKET)
 			rc = -EIO;
 	}

 	return rc;
 }

 static int w8001_open(struct input_dev *dev)
 {
 	struct w8001 *w8001 = input_get_drvdata(dev);
 	int err;

 	err = mutex_lock_interruptible(&w8001->mutex);
 	if (err)
 		return err;

 	if (w8001->open_count++ == 0) {
 		err = w8001_command(w8001, W8001_CMD_START, false);
 		if (err)
 			w8001->open_count--;
 	}

 	mutex_unlock(&w8001->mutex);
 	return err;
 }

 static void w8001_close(struct input_dev *dev)
 {
 	struct w8001 *w8001 = input_get_drvdata(dev);

 	mutex_lock(&w8001->mutex);

 	if (--w8001->open_count == 0)
 		w8001_command(w8001, W8001_CMD_STOP, false);

 	mutex_unlock(&w8001->mutex);
 }

 static int w8001_detect(struct w8001 *w8001)
 {
 	int error;

 	error = w8001_command(w8001, W8001_CMD_STOP, false);
 	if (error)
 		return error;

 	msleep(250);	/* wait 250ms before querying the device */

 	return 0;
 }

 static int w8001_setup_pen(struct w8001 *w8001, char *basename,
 			   size_t basename_sz)
 {
 	struct input_dev *dev = w8001->pen_dev;
 	struct w8001_coord coord;
 	int error;

 	/* penabled? */
 	error = w8001_command(w8001, W8001_CMD_QUERY, true);
 	if (error)
 		return error;

 	__set_bit(EV_KEY, dev->evbit);
 	__set_bit(EV_ABS, dev->evbit);
 	__set_bit(BTN_TOUCH, dev->keybit);
 	__set_bit(BTN_TOOL_PEN, dev->keybit);
 	__set_bit(BTN_TOOL_RUBBER, dev->keybit);
 	__set_bit(BTN_STYLUS, dev->keybit);
 	__set_bit(BTN_STYLUS2, dev->keybit);
 	__set_bit(INPUT_PROP_DIRECT, dev->propbit);

 	parse_pen_data(w8001->response, &coord);
 	w8001->max_pen_x = coord.x;
 	w8001->max_pen_y = coord.y;

 	input_set_abs_params(dev, ABS_X, 0, coord.x, 0, 0);
 	input_set_abs_params(dev, ABS_Y, 0, coord.y, 0, 0);
 	input_abs_set_res(dev, ABS_X, W8001_PEN_RESOLUTION);
 	input_abs_set_res(dev, ABS_Y, W8001_PEN_RESOLUTION);
 	input_set_abs_params(dev, ABS_PRESSURE, 0, coord.pen_pressure, 0, 0);
 	if (coord.tilt_x && coord.tilt_y) {
 		input_set_abs_params(dev, ABS_TILT_X, 0, coord.tilt_x, 0, 0);
 		input_set_abs_params(dev, ABS_TILT_Y, 0, coord.tilt_y, 0, 0);
 	}

 	w8001->id = 0x90;
 	strlcat(basename, " Penabled", basename_sz);

 	return 0;
 }

 static int w8001_setup_touch(struct w8001 *w8001, char *basename,
 			     size_t basename_sz)
 {
 	struct input_dev *dev = w8001->touch_dev;
 	struct w8001_touch_query touch;
 	int error;


 	/* Touch enabled? */
 	error = w8001_command(w8001, W8001_CMD_TOUCHQUERY, true);
 	if (error)
 		return error;
 	/*
 	 * Some non-touch devices may reply to the touch query. But their
 	 * second byte is empty, which indicates touch is not supported.
 	 */
 	if (!w8001->response[1])
 		return -ENXIO;

 	__set_bit(EV_KEY, dev->evbit);
 	__set_bit(EV_ABS, dev->evbit);
 	__set_bit(BTN_TOUCH, dev->keybit);
 	__set_bit(INPUT_PROP_DIRECT, dev->propbit);

 	parse_touchquery(w8001->response, &touch);
 	w8001->max_touch_x = touch.x;
 	w8001->max_touch_y = touch.y;

 	if (w8001->max_pen_x && w8001->max_pen_y) {
 		/* if pen is supported scale to pen maximum */
 		touch.x = w8001->max_pen_x;
 		touch.y = w8001->max_pen_y;
 		touch.panel_res = W8001_PEN_RESOLUTION;
 	}

 	input_set_abs_params(dev, ABS_X, 0, touch.x, 0, 0);
 	input_set_abs_params(dev, ABS_Y, 0, touch.y, 0, 0);
 	input_abs_set_res(dev, ABS_X, touch.panel_res);
 	input_abs_set_res(dev, ABS_Y, touch.panel_res);

 	switch (touch.sensor_id) {
 	case 0:
 	case 2:
 		w8001->pktlen = W8001_PKTLEN_TOUCH93;
 		w8001->id = 0x93;
 		strlcat(basename, " 1FG", basename_sz);
 		break;

 	case 1:
 	case 3:
 	case 4:
 		w8001->pktlen = W8001_PKTLEN_TOUCH9A;
 		strlcat(basename, " 1FG", basename_sz);
 		w8001->id = 0x9a;
 		break;

 	case 5:
 		w8001->pktlen = W8001_PKTLEN_TOUCH2FG;

 		__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
 		input_mt_init_slots(dev, 2, 0);
 		input_set_abs_params(dev, ABS_MT_POSITION_X,
 					0, touch.x, 0, 0);
 		input_set_abs_params(dev, ABS_MT_POSITION_Y,
 					0, touch.y, 0, 0);
 		input_set_abs_params(dev, ABS_MT_TOOL_TYPE,
 					0, MT_TOOL_MAX, 0, 0);

 		strlcat(basename, " 2FG", basename_sz);
 		if (w8001->max_pen_x && w8001->max_pen_y)
 			w8001->id = 0xE3;
 		else
 			w8001->id = 0xE2;
 		break;
 	}

 	strlcat(basename, " Touchscreen", basename_sz);

 	return 0;
 }

 static void w8001_set_devdata(struct input_dev *dev, struct w8001 *w8001,
 			      struct serio *serio)
 {
 	dev->phys = w8001->phys;
 	dev->id.bustype = BUS_RS232;
 	dev->id.product = w8001->id;
 	dev->id.vendor = 0x056a;
 	dev->id.version = 0x0100;
 	dev->open = w8001_open;
 	dev->close = w8001_close;

 	dev->dev.parent = &serio->dev;

 	input_set_drvdata(dev, w8001);
 }

 /*
  * w8001_disconnect() is the opposite of w8001_connect()
  */

 static void w8001_disconnect(struct serio *serio)
 {
 	struct w8001 *w8001 = serio_get_drvdata(serio);

 	serio_close(serio);

 	if (w8001->pen_dev)
 		input_unregister_device(w8001->pen_dev);
 	if (w8001->touch_dev)
 		input_unregister_device(w8001->touch_dev);
 	kfree(w8001);

 	serio_set_drvdata(serio, NULL);
 }

 /*
  * w8001_connect() is the routine that is called when someone adds a
  * new serio device that supports the w8001 protocol and registers it as
  * an input device.
  */

 static int w8001_connect(struct serio *serio, struct serio_driver *drv)
 {
 	struct w8001 *w8001;
 	struct input_dev *input_dev_pen;
 	struct input_dev *input_dev_touch;
 	char basename[64];
 	int err, err_pen, err_touch;

 	w8001 = kzalloc(sizeof(struct w8001), GFP_KERNEL);
 	input_dev_pen = input_allocate_device();
 	input_dev_touch = input_allocate_device();
 	if (!w8001 || !input_dev_pen || !input_dev_touch) {
 		err = -ENOMEM;
 		goto fail1;
 	}

 	w8001->serio = serio;
 	w8001->pen_dev = input_dev_pen;
 	w8001->touch_dev = input_dev_touch;
 	mutex_init(&w8001->mutex);
 	init_completion(&w8001->cmd_done);
 	snprintf(w8001->phys, sizeof(w8001->phys), "%s/input0", serio->phys);

 	serio_set_drvdata(serio, w8001);
 	err = serio_open(serio, drv);
 	if (err)
 		goto fail2;

 	err = w8001_detect(w8001);
 	if (err)
 		goto fail3;

 	/* For backwards-compatibility we compose the basename based on
 	 * capabilities and then just append the tool type
 	 */
 	strlcpy(basename, "Wacom Serial", sizeof(basename));

 	err_pen = w8001_setup_pen(w8001, basename, sizeof(basename));
 	err_touch = w8001_setup_touch(w8001, basename, sizeof(basename));
 	if (err_pen && err_touch) {
 		err = -ENXIO;
 		goto fail3;
 	}

 	if (!err_pen) {
 		strlcpy(w8001->pen_name, basename, sizeof(w8001->pen_name));
 		strlcat(w8001->pen_name, " Pen", sizeof(w8001->pen_name));
 		input_dev_pen->name = w8001->pen_name;

 		w8001_set_devdata(input_dev_pen, w8001, serio);

 		err = input_register_device(w8001->pen_dev);
 		if (err)
 			goto fail3;
 	} else {
 		input_free_device(input_dev_pen);
 		input_dev_pen = NULL;
 		w8001->pen_dev = NULL;
 	}

 	if (!err_touch) {
 		strlcpy(w8001->touch_name, basename, sizeof(w8001->touch_name));
 		strlcat(w8001->touch_name, " Finger",
 			sizeof(w8001->touch_name));
 		input_dev_touch->name = w8001->touch_name;

 		w8001_set_devdata(input_dev_touch, w8001, serio);

 		err = input_register_device(w8001->touch_dev);
 		if (err)
 			goto fail4;
 	} else {
 		input_free_device(input_dev_touch);
 		input_dev_touch = NULL;
 		w8001->touch_dev = NULL;
 	}

 	return 0;

 fail4:
 	if (w8001->pen_dev)
 		input_unregister_device(w8001->pen_dev);
 fail3:
 	serio_close(serio);
 fail2:
 	serio_set_drvdata(serio, NULL);
 fail1:
 	input_free_device(input_dev_pen);
 	input_free_device(input_dev_touch);
 	kfree(w8001);
 	return err;
 }

 static struct serio_device_id w8001_serio_ids[] = {
 	{
 		.type	= SERIO_RS232,
 		.proto	= SERIO_W8001,
 		.id	= SERIO_ANY,
 		.extra	= SERIO_ANY,
 	},
 	{ 0 }
 };

 MODULE_DEVICE_TABLE(serio, w8001_serio_ids);

 static struct serio_driver w8001_drv = {
 	.driver		= {
 		.name	= "w8001",
 	},
 	.description	= DRIVER_DESC,
 	.id_table	= w8001_serio_ids,
 	.interrupt	= w8001_interrupt,
 	.connect	= w8001_connect,
 	.disconnect	= w8001_disconnect,
 };

 module_serio_driver(w8001_drv);
	/*
	* Wacom W8001 penabled serial touchscreen driver
	*
	* Copyright (c) 2008 Jaya Kumar
	* Copyright (c) 2010 Red Hat, Inc.
	* Copyright (c) 2010 - 2011 Ping Cheng, Wacom. <pingc@wacom.com>
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file COPYING in the main directory of this archive for
	* more details.
	*
	* Layout based on Elo serial touchscreen driver by Vojtech Pavlik
	*/

	#include <linux/errno.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/input/mt.h>
	#include <linux/serio.h>
	#include <linux/ctype.h>
	#include <linux/delay.h>

	#define DRIVER_DESC "Wacom W8001 serial touchscreen driver"

	MODULE_AUTHOR("Jaya Kumar <jayakumar.lkml@gmail.com>");
	MODULE_DESCRIPTION(DRIVER_DESC);
	MODULE_LICENSE("GPL");

	#define W8001_MAX_LENGTH 13
	#define W8001_LEAD_MASK 0x80
	#define W8001_LEAD_BYTE 0x80
	#define W8001_TAB_MASK 0x40
	#define W8001_TAB_BYTE 0x40
	/* set in first byte of touch data packets */
	#define W8001_TOUCH_MASK (0x10 \| W8001_LEAD_MASK)
	#define W8001_TOUCH_BYTE (0x10 \| W8001_LEAD_BYTE)

	#define W8001_QUERY_PACKET 0x20

	#define W8001_CMD_STOP '0'
	#define W8001_CMD_START '1'
	#define W8001_CMD_QUERY '*'
	#define W8001_CMD_TOUCHQUERY '%'

	/* length of data packets in bytes, depends on device. */
	#define W8001_PKTLEN_TOUCH93 5
	#define W8001_PKTLEN_TOUCH9A 7
	#define W8001_PKTLEN_TPCPEN 9
	#define W8001_PKTLEN_TPCCTL 11 /* control packet */
	#define W8001_PKTLEN_TOUCH2FG 13

	/* resolution in points/mm */
	#define W8001_PEN_RESOLUTION 100
	#define W8001_TOUCH_RESOLUTION 10

	struct w8001_coord {
	u8 rdy;
	u8 tsw;
	u8 f1;
	u8 f2;
	u16 x;
	u16 y;
	u16 pen_pressure;
	u8 tilt_x;
	u8 tilt_y;
	};

	/* touch query reply packet */
	struct w8001_touch_query {
	u16 x;
	u16 y;
	u8 panel_res;
	u8 capacity_res;
	u8 sensor_id;
	};

	/*
	* Per-touchscreen data.
	*/

	struct w8001 {
	struct input_dev *pen_dev;
	struct input_dev *touch_dev;
	struct serio *serio;
	struct completion cmd_done;
	int id;
	int idx;
	unsigned char response_type;
	unsigned char response[W8001_MAX_LENGTH];
	unsigned char data[W8001_MAX_LENGTH];
	char phys[32];
	int type;
	unsigned int pktlen;
	u16 max_touch_x;
	u16 max_touch_y;
	u16 max_pen_x;
	u16 max_pen_y;
	char pen_name[64];
	char touch_name[64];
	int open_count;
	struct mutex mutex;
	};

	static void parse_pen_data(u8 data, struct w8001_coord coord)
	{
	memset(coord, 0, sizeof(*coord));

	coord->rdy = data[0] & 0x20;
	coord->tsw = data[0] & 0x01;
	coord->f1 = data[0] & 0x02;
	coord->f2 = data[0] & 0x04;

	coord->x = (data[1] & 0x7F) << 9;
	coord->x \|= (data[2] & 0x7F) << 2;
	coord->x \|= (data[6] & 0x60) >> 5;

	coord->y = (data[3] & 0x7F) << 9;
	coord->y \|= (data[4] & 0x7F) << 2;
	coord->y \|= (data[6] & 0x18) >> 3;

	coord->pen_pressure = data[5] & 0x7F;
	coord->pen_pressure \|= (data[6] & 0x07) << 7 ;

	coord->tilt_x = data[7] & 0x7F;
	coord->tilt_y = data[8] & 0x7F;
	}

	static void parse_single_touch(u8 data, struct w8001_coord coord)
	{
	coord->x = (data[1] << 7) \| data[2];
	coord->y = (data[3] << 7) \| data[4];
	coord->tsw = data[0] & 0x01;
	}

	static void scale_touch_coordinates(struct w8001 *w8001,
	unsigned int x, unsigned int y)
	{
	if (w8001->max_pen_x && w8001->max_touch_x)
	x = x * w8001->max_pen_x / w8001->max_touch_x;

	if (w8001->max_pen_y && w8001->max_touch_y)
	y = y * w8001->max_pen_y / w8001->max_touch_y;
	}

	static void parse_multi_touch(struct w8001 *w8001)
	{
	struct input_dev *dev = w8001->touch_dev;
	unsigned char *data = w8001->data;
	unsigned int x, y;
	int i;
	int count = 0;

	for (i = 0; i < 2; i++) {
	bool touch = data[0] & (1 << i);

	input_mt_slot(dev, i);
	input_mt_report_slot_state(dev, MT_TOOL_FINGER, touch);
	if (touch) {
	x = (data[6 * i + 1] << 7) \| data[6 * i + 2];
	y = (data[6 * i + 3] << 7) \| data[6 * i + 4];
	/* data[5,6] and [11,12] is finger capacity */

	/* scale to pen maximum */
	scale_touch_coordinates(w8001, &x, &y);

	input_report_abs(dev, ABS_MT_POSITION_X, x);
	input_report_abs(dev, ABS_MT_POSITION_Y, y);
	count++;
	}
	}

	/* emulate single touch events when stylus is out of proximity.
	* This is to make single touch backward support consistent
	* across all Wacom single touch devices.
	*/
	if (w8001->type != BTN_TOOL_PEN &&
	w8001->type != BTN_TOOL_RUBBER) {
	w8001->type = count == 1 ? BTN_TOOL_FINGER : KEY_RESERVED;
	input_mt_report_pointer_emulation(dev, true);
	}

	input_sync(dev);
	}

	static void parse_touchquery(u8 data, struct w8001_touch_query query)
	{
	memset(query, 0, sizeof(*query));

	query->panel_res = data[1];
	query->sensor_id = data[2] & 0x7;
	query->capacity_res = data[7];

	query->x = data[3] << 9;
	query->x \|= data[4] << 2;
	query->x \|= (data[2] >> 5) & 0x3;

	query->y = data[5] << 9;
	query->y \|= data[6] << 2;
	query->y \|= (data[2] >> 3) & 0x3;

	/* Early days' single-finger touch models need the following defaults */
	if (!query->x && !query->y) {
	query->x = 1024;
	query->y = 1024;
	if (query->panel_res)
	query->x = query->y = (1 << query->panel_res);
	query->panel_res = W8001_TOUCH_RESOLUTION;
	}
	}

	static void report_pen_events(struct w8001 w8001, struct w8001_coord coord)
	{
	struct input_dev *dev = w8001->pen_dev;

	/*
	* We have 1 bit for proximity (rdy) and 3 bits for tip, side,
	* side2/eraser. If rdy && f2 are set, this can be either pen + side2,
	* or eraser. Assume:
	* - if dev is already in proximity and f2 is toggled → pen + side2
	* - if dev comes into proximity with f2 set → eraser
	* If f2 disappears after assuming eraser, fake proximity out for
	* eraser and in for pen.
	*/

	switch (w8001->type) {
	case BTN_TOOL_RUBBER:
	if (!coord->f2) {
	input_report_abs(dev, ABS_PRESSURE, 0);
	input_report_key(dev, BTN_TOUCH, 0);
	input_report_key(dev, BTN_STYLUS, 0);
	input_report_key(dev, BTN_STYLUS2, 0);
	input_report_key(dev, BTN_TOOL_RUBBER, 0);
	input_sync(dev);
	w8001->type = BTN_TOOL_PEN;
	}
	break;

	case BTN_TOOL_FINGER:
	case KEY_RESERVED:
	w8001->type = coord->f2 ? BTN_TOOL_RUBBER : BTN_TOOL_PEN;
	break;

	default:
	input_report_key(dev, BTN_STYLUS2, coord->f2);
	break;
	}

	input_report_abs(dev, ABS_X, coord->x);
	input_report_abs(dev, ABS_Y, coord->y);
	input_report_abs(dev, ABS_PRESSURE, coord->pen_pressure);
	input_report_key(dev, BTN_TOUCH, coord->tsw);
	input_report_key(dev, BTN_STYLUS, coord->f1);
	input_report_key(dev, w8001->type, coord->rdy);
	input_sync(dev);

	if (!coord->rdy)
	w8001->type = KEY_RESERVED;
	}

	static void report_single_touch(struct w8001 w8001, struct w8001_coord coord)
	{
	struct input_dev *dev = w8001->touch_dev;
	unsigned int x = coord->x;
	unsigned int y = coord->y;

	/* scale to pen maximum */
	scale_touch_coordinates(w8001, &x, &y);

	input_report_abs(dev, ABS_X, x);
	input_report_abs(dev, ABS_Y, y);
	input_report_key(dev, BTN_TOUCH, coord->tsw);

	input_sync(dev);

	w8001->type = coord->tsw ? BTN_TOOL_FINGER : KEY_RESERVED;
	}

	static irqreturn_t w8001_interrupt(struct serio *serio,
	unsigned char data, unsigned int flags)
	{
	struct w8001 *w8001 = serio_get_drvdata(serio);
	struct w8001_coord coord;
	unsigned char tmp;

	w8001->data[w8001->idx] = data;
	switch (w8001->idx++) {
	case 0:
	if ((data & W8001_LEAD_MASK) != W8001_LEAD_BYTE) {
	pr_debug("w8001: unsynchronized data: 0x%02x\n", data);
	w8001->idx = 0;
	}
	break;

	case W8001_PKTLEN_TOUCH93 - 1:
	case W8001_PKTLEN_TOUCH9A - 1:
	tmp = w8001->data[0] & W8001_TOUCH_BYTE;
	if (tmp != W8001_TOUCH_BYTE)
	break;

	if (w8001->pktlen == w8001->idx) {
	w8001->idx = 0;
	if (w8001->type != BTN_TOOL_PEN &&
	w8001->type != BTN_TOOL_RUBBER) {
	parse_single_touch(w8001->data, &coord);
	report_single_touch(w8001, &coord);
	}
	}
	break;

	/* Pen coordinates packet */
	case W8001_PKTLEN_TPCPEN - 1:
	tmp = w8001->data[0] & W8001_TAB_MASK;
	if (unlikely(tmp == W8001_TAB_BYTE))
	break;

	tmp = w8001->data[0] & W8001_TOUCH_BYTE;
	if (tmp == W8001_TOUCH_BYTE)
	break;

	w8001->idx = 0;
	parse_pen_data(w8001->data, &coord);
	report_pen_events(w8001, &coord);
	break;

	/* control packet */
	case W8001_PKTLEN_TPCCTL - 1:
	tmp = w8001->data[0] & W8001_TOUCH_MASK;
	if (tmp == W8001_TOUCH_BYTE)
	break;

	w8001->idx = 0;
	memcpy(w8001->response, w8001->data, W8001_MAX_LENGTH);
	w8001->response_type = W8001_QUERY_PACKET;
	complete(&w8001->cmd_done);
	break;

	/* 2 finger touch packet */
	case W8001_PKTLEN_TOUCH2FG - 1:
	w8001->idx = 0;
	parse_multi_touch(w8001);
	break;

	default:
	/*
	* ThinkPad X60 Tablet PC (pen only device) sometimes
	* sends invalid data packets that are larger than
	* W8001_PKTLEN_TPCPEN. Let's start over again.
	*/
	if (!w8001->touch_dev && w8001->idx > W8001_PKTLEN_TPCPEN - 1)
	w8001->idx = 0;
	}

	return IRQ_HANDLED;
	}

	static int w8001_command(struct w8001 *w8001, unsigned char command,
	bool wait_response)
	{
	int rc;

	w8001->response_type = 0;
	init_completion(&w8001->cmd_done);

	rc = serio_write(w8001->serio, command);
	if (rc == 0 && wait_response) {

	wait_for_completion_timeout(&w8001->cmd_done, HZ);
	if (w8001->response_type != W8001_QUERY_PACKET)
	rc = -EIO;
	}

	return rc;
	}

	static int w8001_open(struct input_dev *dev)
	{
	struct w8001 *w8001 = input_get_drvdata(dev);
	int err;

	err = mutex_lock_interruptible(&w8001->mutex);
	if (err)
	return err;

	if (w8001->open_count++ == 0) {
	err = w8001_command(w8001, W8001_CMD_START, false);
	if (err)
	w8001->open_count--;
	}

	mutex_unlock(&w8001->mutex);
	return err;
	}

	static void w8001_close(struct input_dev *dev)
	{
	struct w8001 *w8001 = input_get_drvdata(dev);

	mutex_lock(&w8001->mutex);

	if (--w8001->open_count == 0)
	w8001_command(w8001, W8001_CMD_STOP, false);

	mutex_unlock(&w8001->mutex);
	}

	static int w8001_detect(struct w8001 *w8001)
	{
	int error;

	error = w8001_command(w8001, W8001_CMD_STOP, false);
	if (error)
	return error;

	msleep(250); /* wait 250ms before querying the device */

	return 0;
	}

	static int w8001_setup_pen(struct w8001 w8001, char basename,
	size_t basename_sz)
	{
	struct input_dev *dev = w8001->pen_dev;
	struct w8001_coord coord;
	int error;

	/* penabled? */
	error = w8001_command(w8001, W8001_CMD_QUERY, true);
	if (error)
	return error;

	__set_bit(EV_KEY, dev->evbit);
	__set_bit(EV_ABS, dev->evbit);
	__set_bit(BTN_TOUCH, dev->keybit);
	__set_bit(BTN_TOOL_PEN, dev->keybit);
	__set_bit(BTN_TOOL_RUBBER, dev->keybit);
	__set_bit(BTN_STYLUS, dev->keybit);
	__set_bit(BTN_STYLUS2, dev->keybit);
	__set_bit(INPUT_PROP_DIRECT, dev->propbit);

	parse_pen_data(w8001->response, &coord);
	w8001->max_pen_x = coord.x;
	w8001->max_pen_y = coord.y;

	input_set_abs_params(dev, ABS_X, 0, coord.x, 0, 0);
	input_set_abs_params(dev, ABS_Y, 0, coord.y, 0, 0);
	input_abs_set_res(dev, ABS_X, W8001_PEN_RESOLUTION);
	input_abs_set_res(dev, ABS_Y, W8001_PEN_RESOLUTION);
	input_set_abs_params(dev, ABS_PRESSURE, 0, coord.pen_pressure, 0, 0);
	if (coord.tilt_x && coord.tilt_y) {
	input_set_abs_params(dev, ABS_TILT_X, 0, coord.tilt_x, 0, 0);
	input_set_abs_params(dev, ABS_TILT_Y, 0, coord.tilt_y, 0, 0);
	}

	w8001->id = 0x90;
	strlcat(basename, " Penabled", basename_sz);

	return 0;
	}

	static int w8001_setup_touch(struct w8001 w8001, char basename,
	size_t basename_sz)
	{
	struct input_dev *dev = w8001->touch_dev;
	struct w8001_touch_query touch;
	int error;


	/* Touch enabled? */
	error = w8001_command(w8001, W8001_CMD_TOUCHQUERY, true);
	if (error)
	return error;
	/*
	* Some non-touch devices may reply to the touch query. But their
	* second byte is empty, which indicates touch is not supported.
	*/
	if (!w8001->response[1])
	return -ENXIO;

	__set_bit(EV_KEY, dev->evbit);
	__set_bit(EV_ABS, dev->evbit);
	__set_bit(BTN_TOUCH, dev->keybit);
	__set_bit(INPUT_PROP_DIRECT, dev->propbit);

	parse_touchquery(w8001->response, &touch);
	w8001->max_touch_x = touch.x;
	w8001->max_touch_y = touch.y;

	if (w8001->max_pen_x && w8001->max_pen_y) {
	/* if pen is supported scale to pen maximum */
	touch.x = w8001->max_pen_x;
	touch.y = w8001->max_pen_y;
	touch.panel_res = W8001_PEN_RESOLUTION;
	}

	input_set_abs_params(dev, ABS_X, 0, touch.x, 0, 0);
	input_set_abs_params(dev, ABS_Y, 0, touch.y, 0, 0);
	input_abs_set_res(dev, ABS_X, touch.panel_res);
	input_abs_set_res(dev, ABS_Y, touch.panel_res);

	switch (touch.sensor_id) {
	case 0:
	case 2:
	w8001->pktlen = W8001_PKTLEN_TOUCH93;
	w8001->id = 0x93;
	strlcat(basename, " 1FG", basename_sz);
	break;

	case 1:
	case 3:
	case 4:
	w8001->pktlen = W8001_PKTLEN_TOUCH9A;
	strlcat(basename, " 1FG", basename_sz);
	w8001->id = 0x9a;
	break;

	case 5:
	w8001->pktlen = W8001_PKTLEN_TOUCH2FG;

	__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
	input_mt_init_slots(dev, 2, 0);
	input_set_abs_params(dev, ABS_MT_POSITION_X,
	0, touch.x, 0, 0);
	input_set_abs_params(dev, ABS_MT_POSITION_Y,
	0, touch.y, 0, 0);
	input_set_abs_params(dev, ABS_MT_TOOL_TYPE,
	0, MT_TOOL_MAX, 0, 0);

	strlcat(basename, " 2FG", basename_sz);
	if (w8001->max_pen_x && w8001->max_pen_y)
	w8001->id = 0xE3;
	else
	w8001->id = 0xE2;
	break;
	}

	strlcat(basename, " Touchscreen", basename_sz);

	return 0;
	}

	static void w8001_set_devdata(struct input_dev dev, struct w8001 w8001,
	struct serio *serio)
	{
	dev->phys = w8001->phys;
	dev->id.bustype = BUS_RS232;
	dev->id.product = w8001->id;
	dev->id.vendor = 0x056a;
	dev->id.version = 0x0100;
	dev->open = w8001_open;
	dev->close = w8001_close;

	dev->dev.parent = &serio->dev;

	input_set_drvdata(dev, w8001);
	}

	/*
	* w8001_disconnect() is the opposite of w8001_connect()
	*/

	static void w8001_disconnect(struct serio *serio)
	{
	struct w8001 *w8001 = serio_get_drvdata(serio);

	serio_close(serio);

	if (w8001->pen_dev)
	input_unregister_device(w8001->pen_dev);
	if (w8001->touch_dev)
	input_unregister_device(w8001->touch_dev);
	kfree(w8001);

	serio_set_drvdata(serio, NULL);
	}

	/*
	* w8001_connect() is the routine that is called when someone adds a
	* new serio device that supports the w8001 protocol and registers it as
	* an input device.
	*/

	static int w8001_connect(struct serio serio, struct serio_driver drv)
	{
	struct w8001 *w8001;
	struct input_dev *input_dev_pen;
	struct input_dev *input_dev_touch;
	char basename[64];
	int err, err_pen, err_touch;

	w8001 = kzalloc(sizeof(struct w8001), GFP_KERNEL);
	input_dev_pen = input_allocate_device();
	input_dev_touch = input_allocate_device();
	if (!w8001 \|\| !input_dev_pen \|\| !input_dev_touch) {
	err = -ENOMEM;
	goto fail1;
	}

	w8001->serio = serio;
	w8001->pen_dev = input_dev_pen;
	w8001->touch_dev = input_dev_touch;
	mutex_init(&w8001->mutex);
	init_completion(&w8001->cmd_done);
	snprintf(w8001->phys, sizeof(w8001->phys), "%s/input0", serio->phys);

	serio_set_drvdata(serio, w8001);
	err = serio_open(serio, drv);
	if (err)
	goto fail2;

	err = w8001_detect(w8001);
	if (err)
	goto fail3;

	/* For backwards-compatibility we compose the basename based on
	* capabilities and then just append the tool type
	*/
	strlcpy(basename, "Wacom Serial", sizeof(basename));

	err_pen = w8001_setup_pen(w8001, basename, sizeof(basename));
	err_touch = w8001_setup_touch(w8001, basename, sizeof(basename));
	if (err_pen && err_touch) {
	err = -ENXIO;
	goto fail3;
	}

	if (!err_pen) {
	strlcpy(w8001->pen_name, basename, sizeof(w8001->pen_name));
	strlcat(w8001->pen_name, " Pen", sizeof(w8001->pen_name));
	input_dev_pen->name = w8001->pen_name;

	w8001_set_devdata(input_dev_pen, w8001, serio);

	err = input_register_device(w8001->pen_dev);
	if (err)
	goto fail3;
	} else {
	input_free_device(input_dev_pen);
	input_dev_pen = NULL;
	w8001->pen_dev = NULL;
	}

	if (!err_touch) {
	strlcpy(w8001->touch_name, basename, sizeof(w8001->touch_name));
	strlcat(w8001->touch_name, " Finger",
	sizeof(w8001->touch_name));
	input_dev_touch->name = w8001->touch_name;

	w8001_set_devdata(input_dev_touch, w8001, serio);

	err = input_register_device(w8001->touch_dev);
	if (err)
	goto fail4;
	} else {
	input_free_device(input_dev_touch);
	input_dev_touch = NULL;
	w8001->touch_dev = NULL;
	}

	return 0;

	fail4:
	if (w8001->pen_dev)
	input_unregister_device(w8001->pen_dev);
	fail3:
	serio_close(serio);
	fail2:
	serio_set_drvdata(serio, NULL);
	fail1:
	input_free_device(input_dev_pen);
	input_free_device(input_dev_touch);
	kfree(w8001);
	return err;
	}

	static struct serio_device_id w8001_serio_ids[] = {
	{
	.type = SERIO_RS232,
	.proto = SERIO_W8001,
	.id = SERIO_ANY,
	.extra = SERIO_ANY,
	},
	{ 0 }
	};

	MODULE_DEVICE_TABLE(serio, w8001_serio_ids);

	static struct serio_driver w8001_drv = {
	.driver = {
	.name = "w8001",
	},
	.description = DRIVER_DESC,
	.id_table = w8001_serio_ids,
	.interrupt = w8001_interrupt,
	.connect = w8001_connect,
	.disconnect = w8001_disconnect,
	};

	module_serio_driver(w8001_drv);