drivers/mfd/ucb1x00-ts.c - arm/linux-arm64-legacy - Git at Google

 /*
  *  Touchscreen driver for UCB1x00-based touchscreens
  *
  *  Copyright (C) 2001 Russell King, All Rights Reserved.
  *  Copyright (C) 2005 Pavel Machek
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * 21-Jan-2002 <jco@ict.es> :
  *
  * Added support for synchronous A/D mode. This mode is useful to
  * avoid noise induced in the touchpanel by the LCD, provided that
  * the UCB1x00 has a valid LCD sync signal routed to its ADCSYNC pin.
  * It is important to note that the signal connected to the ADCSYNC
  * pin should provide pulses even when the LCD is blanked, otherwise
  * a pen touch needed to unblank the LCD will never be read.
  */
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/init.h>
 #include <linux/smp.h>
 #include <linux/sched.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/string.h>
 #include <linux/input.h>
 #include <linux/device.h>
 #include <linux/freezer.h>
 #include <linux/slab.h>
 #include <linux/kthread.h>

 #include <asm/dma.h>
 #include <asm/semaphore.h>
 #include <asm/arch/collie.h>
 #include <asm/mach-types.h>

 #include "ucb1x00.h"


 struct ucb1x00_ts {
 	struct input_dev	*idev;
 	struct ucb1x00		*ucb;

 	wait_queue_head_t	irq_wait;
 	struct task_struct	*rtask;
 	u16			x_res;
 	u16			y_res;

 	unsigned int		restart:1;
 	unsigned int		adcsync:1;
 };

 static int adcsync;

 static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
 {
 	struct input_dev *idev = ts->idev;

 	input_report_abs(idev, ABS_X, x);
 	input_report_abs(idev, ABS_Y, y);
 	input_report_abs(idev, ABS_PRESSURE, pressure);
 	input_sync(idev);
 }

 static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
 {
 	struct input_dev *idev = ts->idev;

 	input_report_abs(idev, ABS_PRESSURE, 0);
 	input_sync(idev);
 }

 /*
  * Switch to interrupt mode.
  */
 static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
 {
 	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 			UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
 			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
 			UCB_TS_CR_MODE_INT);
 }

 /*
  * Switch to pressure mode, and read pressure.  We don't need to wait
  * here, since both plates are being driven.
  */
 static inline unsigned int ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
 {
 	if (machine_is_collie()) {
 		ucb1x00_io_write(ts->ucb, COLLIE_TC35143_GPIO_TBL_CHK, 0);
 		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 				  UCB_TS_CR_TSPX_POW | UCB_TS_CR_TSMX_POW |
 				  UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);

 		udelay(55);

 		return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_AD2, ts->adcsync);
 	} else {
 		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 				  UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
 				  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
 				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);

 		return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
 	}
 }

 /*
  * Switch to X position mode and measure Y plate.  We switch the plate
  * configuration in pressure mode, then switch to position mode.  This
  * gives a faster response time.  Even so, we need to wait about 55us
  * for things to stabilise.
  */
 static inline unsigned int ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
 {
 	if (machine_is_collie())
 		ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
 	else {
 		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 				  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 				  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 	}
 	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);

 	udelay(55);

 	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
 }

 /*
  * Switch to Y position mode and measure X plate.  We switch the plate
  * configuration in pressure mode, then switch to position mode.  This
  * gives a faster response time.  Even so, we need to wait about 55us
  * for things to stabilise.
  */
 static inline unsigned int ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
 {
 	if (machine_is_collie())
 		ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
 	else {
 		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 				  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 				  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 	}

 	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);

 	udelay(55);

 	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
 }

 /*
  * Switch to X plate resistance mode.  Set MX to ground, PX to
  * supply.  Measure current.
  */
 static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
 {
 	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 	return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
 }

 /*
  * Switch to Y plate resistance mode.  Set MY to ground, PY to
  * supply.  Measure current.
  */
 static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
 {
 	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 	return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
 }

 static inline int ucb1x00_ts_pen_down(struct ucb1x00_ts *ts)
 {
 	unsigned int val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);

 	if (machine_is_collie())
 		return (!(val & (UCB_TS_CR_TSPX_LOW)));
 	else
 		return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
 }

 /*
  * This is a RT kernel thread that handles the ADC accesses
  * (mainly so we can use semaphores in the UCB1200 core code
  * to serialise accesses to the ADC).
  */
 static int ucb1x00_thread(void *_ts)
 {
 	struct ucb1x00_ts *ts = _ts;
 	struct task_struct *tsk = current;
 	DECLARE_WAITQUEUE(wait, tsk);
 	int valid = 0;

 	add_wait_queue(&ts->irq_wait, &wait);
 	while (!kthread_should_stop()) {
 		unsigned int x, y, p;
 		signed long timeout;

 		ts->restart = 0;

 		ucb1x00_adc_enable(ts->ucb);

 		x = ucb1x00_ts_read_xpos(ts);
 		y = ucb1x00_ts_read_ypos(ts);
 		p = ucb1x00_ts_read_pressure(ts);

 		/*
 		 * Switch back to interrupt mode.
 		 */
 		ucb1x00_ts_mode_int(ts);
 		ucb1x00_adc_disable(ts->ucb);

 		msleep(10);

 		ucb1x00_enable(ts->ucb);


 		if (ucb1x00_ts_pen_down(ts)) {
 			set_task_state(tsk, TASK_INTERRUPTIBLE);

 			ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, machine_is_collie() ? UCB_RISING : UCB_FALLING);
 			ucb1x00_disable(ts->ucb);

 			/*
 			 * If we spat out a valid sample set last time,
 			 * spit out a "pen off" sample here.
 			 */
 			if (valid) {
 				ucb1x00_ts_event_release(ts);
 				valid = 0;
 			}

 			timeout = MAX_SCHEDULE_TIMEOUT;
 		} else {
 			ucb1x00_disable(ts->ucb);

 			/*
 			 * Filtering is policy.  Policy belongs in user
 			 * space.  We therefore leave it to user space
 			 * to do any filtering they please.
 			 */
 			if (!ts->restart) {
 				ucb1x00_ts_evt_add(ts, p, x, y);
 				valid = 1;
 			}

 			set_task_state(tsk, TASK_INTERRUPTIBLE);
 			timeout = HZ / 100;
 		}

 		try_to_freeze();

 		schedule_timeout(timeout);
 	}

 	remove_wait_queue(&ts->irq_wait, &wait);

 	ts->rtask = NULL;
 	return 0;
 }

 /*
  * We only detect touch screen _touches_ with this interrupt
  * handler, and even then we just schedule our task.
  */
 static void ucb1x00_ts_irq(int idx, void *id)
 {
 	struct ucb1x00_ts *ts = id;

 	ucb1x00_disable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
 	wake_up(&ts->irq_wait);
 }

 static int ucb1x00_ts_open(struct input_dev *idev)
 {
 	struct ucb1x00_ts *ts = input_get_drvdata(idev);
 	int ret = 0;

 	BUG_ON(ts->rtask);

 	init_waitqueue_head(&ts->irq_wait);
 	ret = ucb1x00_hook_irq(ts->ucb, UCB_IRQ_TSPX, ucb1x00_ts_irq, ts);
 	if (ret < 0)
 		goto out;

 	/*
 	 * If we do this at all, we should allow the user to
 	 * measure and read the X and Y resistance at any time.
 	 */
 	ucb1x00_adc_enable(ts->ucb);
 	ts->x_res = ucb1x00_ts_read_xres(ts);
 	ts->y_res = ucb1x00_ts_read_yres(ts);
 	ucb1x00_adc_disable(ts->ucb);

 	ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
 	if (!IS_ERR(ts->rtask)) {
 		ret = 0;
 	} else {
 		ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 		ts->rtask = NULL;
 		ret = -EFAULT;
 	}

  out:
 	return ret;
 }

 /*
  * Release touchscreen resources.  Disable IRQs.
  */
 static void ucb1x00_ts_close(struct input_dev *idev)
 {
 	struct ucb1x00_ts *ts = input_get_drvdata(idev);

 	if (ts->rtask)
 		kthread_stop(ts->rtask);

 	ucb1x00_enable(ts->ucb);
 	ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 	ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
 	ucb1x00_disable(ts->ucb);
 }

 #ifdef CONFIG_PM
 static int ucb1x00_ts_resume(struct ucb1x00_dev *dev)
 {
 	struct ucb1x00_ts *ts = dev->priv;

 	if (ts->rtask != NULL) {
 		/*
 		 * Restart the TS thread to ensure the
 		 * TS interrupt mode is set up again
 		 * after sleep.
 		 */
 		ts->restart = 1;
 		wake_up(&ts->irq_wait);
 	}
 	return 0;
 }
 #else
 #define ucb1x00_ts_resume NULL
 #endif


 /*
  * Initialisation.
  */
 static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
 {
 	struct ucb1x00_ts *ts;
 	struct input_dev *idev;
 	int err;

 	ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
 	idev = input_allocate_device();
 	if (!ts || !idev) {
 		err = -ENOMEM;
 		goto fail;
 	}

 	ts->ucb = dev->ucb;
 	ts->idev = idev;
 	ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;

 	idev->name       = "Touchscreen panel";
 	idev->id.product = ts->ucb->id;
 	idev->open       = ucb1x00_ts_open;
 	idev->close      = ucb1x00_ts_close;

 	__set_bit(EV_ABS, idev->evbit);
 	__set_bit(ABS_X, idev->absbit);
 	__set_bit(ABS_Y, idev->absbit);
 	__set_bit(ABS_PRESSURE, idev->absbit);

 	input_set_drvdata(idev, ts);

 	err = input_register_device(idev);
 	if (err)
 		goto fail;

 	dev->priv = ts;

 	return 0;

  fail:
 	input_free_device(idev);
 	kfree(ts);
 	return err;
 }

 static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
 {
 	struct ucb1x00_ts *ts = dev->priv;

 	input_unregister_device(ts->idev);
 	kfree(ts);
 }

 static struct ucb1x00_driver ucb1x00_ts_driver = {
 	.add		= ucb1x00_ts_add,
 	.remove		= ucb1x00_ts_remove,
 	.resume		= ucb1x00_ts_resume,
 };

 static int __init ucb1x00_ts_init(void)
 {
 	return ucb1x00_register_driver(&ucb1x00_ts_driver);
 }

 static void __exit ucb1x00_ts_exit(void)
 {
 	ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 }

 module_param(adcsync, int, 0444);
 module_init(ucb1x00_ts_init);
 module_exit(ucb1x00_ts_exit);

 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 MODULE_LICENSE("GPL");
	/*
	* Touchscreen driver for UCB1x00-based touchscreens
	*
	* Copyright (C) 2001 Russell King, All Rights Reserved.
	* Copyright (C) 2005 Pavel Machek
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* 21-Jan-2002 <jco@ict.es> :
	*
	* Added support for synchronous A/D mode. This mode is useful to
	* avoid noise induced in the touchpanel by the LCD, provided that
	* the UCB1x00 has a valid LCD sync signal routed to its ADCSYNC pin.
	* It is important to note that the signal connected to the ADCSYNC
	* pin should provide pulses even when the LCD is blanked, otherwise
	* a pen touch needed to unblank the LCD will never be read.
	*/
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/init.h>
	#include <linux/smp.h>
	#include <linux/sched.h>
	#include <linux/completion.h>
	#include <linux/delay.h>
	#include <linux/string.h>
	#include <linux/input.h>
	#include <linux/device.h>
	#include <linux/freezer.h>
	#include <linux/slab.h>
	#include <linux/kthread.h>

	#include <asm/dma.h>
	#include <asm/semaphore.h>
	#include <asm/arch/collie.h>
	#include <asm/mach-types.h>

	#include "ucb1x00.h"


	struct ucb1x00_ts {
	struct input_dev *idev;
	struct ucb1x00 *ucb;

	wait_queue_head_t irq_wait;
	struct task_struct *rtask;
	u16 x_res;
	u16 y_res;

	unsigned int restart:1;
	unsigned int adcsync:1;
	};

	static int adcsync;

	static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
	{
	struct input_dev *idev = ts->idev;

	input_report_abs(idev, ABS_X, x);
	input_report_abs(idev, ABS_Y, y);
	input_report_abs(idev, ABS_PRESSURE, pressure);
	input_sync(idev);
	}

	static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
	{
	struct input_dev *idev = ts->idev;

	input_report_abs(idev, ABS_PRESSURE, 0);
	input_sync(idev);
	}

	/*
	* Switch to interrupt mode.
	*/
	static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
	{
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMX_POW \| UCB_TS_CR_TSPX_POW \|
	UCB_TS_CR_TSMY_GND \| UCB_TS_CR_TSPY_GND \|
	UCB_TS_CR_MODE_INT);
	}

	/*
	* Switch to pressure mode, and read pressure. We don't need to wait
	* here, since both plates are being driven.
	*/
	static inline unsigned int ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
	{
	if (machine_is_collie()) {
	ucb1x00_io_write(ts->ucb, COLLIE_TC35143_GPIO_TBL_CHK, 0);
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSPX_POW \| UCB_TS_CR_TSMX_POW \|
	UCB_TS_CR_MODE_POS \| UCB_TS_CR_BIAS_ENA);

	udelay(55);

	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_AD2, ts->adcsync);
	} else {
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMX_POW \| UCB_TS_CR_TSPX_POW \|
	UCB_TS_CR_TSMY_GND \| UCB_TS_CR_TSPY_GND \|
	UCB_TS_CR_MODE_PRES \| UCB_TS_CR_BIAS_ENA);

	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
	}
	}

	/*
	* Switch to X position mode and measure Y plate. We switch the plate
	* configuration in pressure mode, then switch to position mode. This
	* gives a faster response time. Even so, we need to wait about 55us
	* for things to stabilise.
	*/
	static inline unsigned int ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
	{
	if (machine_is_collie())
	ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
	else {
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMX_GND \| UCB_TS_CR_TSPX_POW \|
	UCB_TS_CR_MODE_PRES \| UCB_TS_CR_BIAS_ENA);
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMX_GND \| UCB_TS_CR_TSPX_POW \|
	UCB_TS_CR_MODE_PRES \| UCB_TS_CR_BIAS_ENA);
	}
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMX_GND \| UCB_TS_CR_TSPX_POW \|
	UCB_TS_CR_MODE_POS \| UCB_TS_CR_BIAS_ENA);

	udelay(55);

	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
	}

	/*
	* Switch to Y position mode and measure X plate. We switch the plate
	* configuration in pressure mode, then switch to position mode. This
	* gives a faster response time. Even so, we need to wait about 55us
	* for things to stabilise.
	*/
	static inline unsigned int ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
	{
	if (machine_is_collie())
	ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
	else {
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMY_GND \| UCB_TS_CR_TSPY_POW \|
	UCB_TS_CR_MODE_PRES \| UCB_TS_CR_BIAS_ENA);
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMY_GND \| UCB_TS_CR_TSPY_POW \|
	UCB_TS_CR_MODE_PRES \| UCB_TS_CR_BIAS_ENA);
	}

	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMY_GND \| UCB_TS_CR_TSPY_POW \|
	UCB_TS_CR_MODE_POS \| UCB_TS_CR_BIAS_ENA);

	udelay(55);

	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
	}

	/*
	* Switch to X plate resistance mode. Set MX to ground, PX to
	* supply. Measure current.
	*/
	static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
	{
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMX_GND \| UCB_TS_CR_TSPX_POW \|
	UCB_TS_CR_MODE_PRES \| UCB_TS_CR_BIAS_ENA);
	return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
	}

	/*
	* Switch to Y plate resistance mode. Set MY to ground, PY to
	* supply. Measure current.
	*/
	static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
	{
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
	UCB_TS_CR_TSMY_GND \| UCB_TS_CR_TSPY_POW \|
	UCB_TS_CR_MODE_PRES \| UCB_TS_CR_BIAS_ENA);
	return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
	}

	static inline int ucb1x00_ts_pen_down(struct ucb1x00_ts *ts)
	{
	unsigned int val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);

	if (machine_is_collie())
	return (!(val & (UCB_TS_CR_TSPX_LOW)));
	else
	return (val & (UCB_TS_CR_TSPX_LOW \| UCB_TS_CR_TSMX_LOW));
	}

	/*
	* This is a RT kernel thread that handles the ADC accesses
	* (mainly so we can use semaphores in the UCB1200 core code
	* to serialise accesses to the ADC).
	*/
	static int ucb1x00_thread(void *_ts)
	{
	struct ucb1x00_ts *ts = _ts;
	struct task_struct *tsk = current;
	DECLARE_WAITQUEUE(wait, tsk);
	int valid = 0;

	add_wait_queue(&ts->irq_wait, &wait);
	while (!kthread_should_stop()) {
	unsigned int x, y, p;
	signed long timeout;

	ts->restart = 0;

	ucb1x00_adc_enable(ts->ucb);

	x = ucb1x00_ts_read_xpos(ts);
	y = ucb1x00_ts_read_ypos(ts);
	p = ucb1x00_ts_read_pressure(ts);

	/*
	* Switch back to interrupt mode.
	*/
	ucb1x00_ts_mode_int(ts);
	ucb1x00_adc_disable(ts->ucb);

	msleep(10);

	ucb1x00_enable(ts->ucb);


	if (ucb1x00_ts_pen_down(ts)) {
	set_task_state(tsk, TASK_INTERRUPTIBLE);

	ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, machine_is_collie() ? UCB_RISING : UCB_FALLING);
	ucb1x00_disable(ts->ucb);

	/*
	* If we spat out a valid sample set last time,
	* spit out a "pen off" sample here.
	*/
	if (valid) {
	ucb1x00_ts_event_release(ts);
	valid = 0;
	}

	timeout = MAX_SCHEDULE_TIMEOUT;
	} else {
	ucb1x00_disable(ts->ucb);

	/*
	* Filtering is policy. Policy belongs in user
	* space. We therefore leave it to user space
	* to do any filtering they please.
	*/
	if (!ts->restart) {
	ucb1x00_ts_evt_add(ts, p, x, y);
	valid = 1;
	}

	set_task_state(tsk, TASK_INTERRUPTIBLE);
	timeout = HZ / 100;
	}

	try_to_freeze();

	schedule_timeout(timeout);
	}

	remove_wait_queue(&ts->irq_wait, &wait);

	ts->rtask = NULL;
	return 0;
	}

	/*
	* We only detect touch screen _touches_ with this interrupt
	* handler, and even then we just schedule our task.
	*/
	static void ucb1x00_ts_irq(int idx, void *id)
	{
	struct ucb1x00_ts *ts = id;

	ucb1x00_disable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
	wake_up(&ts->irq_wait);
	}

	static int ucb1x00_ts_open(struct input_dev *idev)
	{
	struct ucb1x00_ts *ts = input_get_drvdata(idev);
	int ret = 0;

	BUG_ON(ts->rtask);

	init_waitqueue_head(&ts->irq_wait);
	ret = ucb1x00_hook_irq(ts->ucb, UCB_IRQ_TSPX, ucb1x00_ts_irq, ts);
	if (ret < 0)
	goto out;

	/*
	* If we do this at all, we should allow the user to
	* measure and read the X and Y resistance at any time.
	*/
	ucb1x00_adc_enable(ts->ucb);
	ts->x_res = ucb1x00_ts_read_xres(ts);
	ts->y_res = ucb1x00_ts_read_yres(ts);
	ucb1x00_adc_disable(ts->ucb);

	ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
	if (!IS_ERR(ts->rtask)) {
	ret = 0;
	} else {
	ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
	ts->rtask = NULL;
	ret = -EFAULT;
	}

	out:
	return ret;
	}

	/*
	* Release touchscreen resources. Disable IRQs.
	*/
	static void ucb1x00_ts_close(struct input_dev *idev)
	{
	struct ucb1x00_ts *ts = input_get_drvdata(idev);

	if (ts->rtask)
	kthread_stop(ts->rtask);

	ucb1x00_enable(ts->ucb);
	ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
	ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
	ucb1x00_disable(ts->ucb);
	}

	#ifdef CONFIG_PM
	static int ucb1x00_ts_resume(struct ucb1x00_dev *dev)
	{
	struct ucb1x00_ts *ts = dev->priv;

	if (ts->rtask != NULL) {
	/*
	* Restart the TS thread to ensure the
	* TS interrupt mode is set up again
	* after sleep.
	*/
	ts->restart = 1;
	wake_up(&ts->irq_wait);
	}
	return 0;
	}
	#else
	#define ucb1x00_ts_resume NULL
	#endif


	/*
	* Initialisation.
	*/
	static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
	{
	struct ucb1x00_ts *ts;
	struct input_dev *idev;
	int err;

	ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
	idev = input_allocate_device();
	if (!ts \|\| !idev) {
	err = -ENOMEM;
	goto fail;
	}

	ts->ucb = dev->ucb;
	ts->idev = idev;
	ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;

	idev->name = "Touchscreen panel";
	idev->id.product = ts->ucb->id;
	idev->open = ucb1x00_ts_open;
	idev->close = ucb1x00_ts_close;

	__set_bit(EV_ABS, idev->evbit);
	__set_bit(ABS_X, idev->absbit);
	__set_bit(ABS_Y, idev->absbit);
	__set_bit(ABS_PRESSURE, idev->absbit);

	input_set_drvdata(idev, ts);

	err = input_register_device(idev);
	if (err)
	goto fail;

	dev->priv = ts;

	return 0;

	fail:
	input_free_device(idev);
	kfree(ts);
	return err;
	}

	static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
	{
	struct ucb1x00_ts *ts = dev->priv;

	input_unregister_device(ts->idev);
	kfree(ts);
	}

	static struct ucb1x00_driver ucb1x00_ts_driver = {
	.add = ucb1x00_ts_add,
	.remove = ucb1x00_ts_remove,
	.resume = ucb1x00_ts_resume,
	};

	static int __init ucb1x00_ts_init(void)
	{
	return ucb1x00_register_driver(&ucb1x00_ts_driver);
	}

	static void __exit ucb1x00_ts_exit(void)
	{
	ucb1x00_unregister_driver(&ucb1x00_ts_driver);
	}

	module_param(adcsync, int, 0444);
	module_init(ucb1x00_ts_init);
	module_exit(ucb1x00_ts_exit);

	MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
	MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
	MODULE_LICENSE("GPL");