// SPDX-License-Identifier: GPL-2.0-only

  /*

   *  Touchscreen driver for UCB1x00-based touchscreens

   *
   *  Copyright (C) 2001 Russell King, All Rights Reserved.

   *  Copyright (C) 2005 Pavel Machek

   *

   * 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/interrupt.h>

  #include <linux/sched.h>

  #include <linux/spinlock.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 <linux/mfd/ucb1x00.h>

  #include <mach/collie.h>

  #include <asm/mach-types.h>

  
  
  struct ucb1x00_ts {

  	struct input_dev	*idev;

  	struct ucb1x00		*ucb;

  	spinlock_t		irq_lock;
  	unsigned		irq_disabled;

  	wait_queue_head_t	irq_wait;

  	struct task_struct	*rtask;

  	u16			x_res;
  	u16			y_res;

  	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_report_key(idev, BTN_TOUCH, 1);

  	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_report_key(idev, BTN_TOUCH, 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;

  	DECLARE_WAITQUEUE(wait, current);

  	bool frozen, ignore = false;

  	int valid = 0;

  	set_freezable();

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

  	while (!kthread_freezable_should_stop(&frozen)) {

  		unsigned int x, y, p;

  		signed long timeout;

  		if (frozen)
  			ignore = true;

  
  		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_current_state(TASK_INTERRUPTIBLE);

  			spin_lock_irq(&ts->irq_lock);
  			if (ts->irq_disabled) {
  				ts->irq_disabled = 0;
  				enable_irq(ts->ucb->irq_base + UCB_IRQ_TSPX);
  			}
  			spin_unlock_irq(&ts->irq_lock);

  			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 (!ignore) {

  				ucb1x00_ts_evt_add(ts, p, x, y);
  				valid = 1;
  			}

  			set_current_state(TASK_INTERRUPTIBLE);

  			timeout = HZ / 100;
  		}

  		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 irqreturn_t ucb1x00_ts_irq(int irq, void *id)

  {
  	struct ucb1x00_ts *ts = id;

  	spin_lock(&ts->irq_lock);
  	ts->irq_disabled = 1;
  	disable_irq_nosync(ts->ucb->irq_base + UCB_IRQ_TSPX);
  	spin_unlock(&ts->irq_lock);

  	wake_up(&ts->irq_wait);

  
  	return IRQ_HANDLED;

  }
  
  static int ucb1x00_ts_open(struct input_dev *idev)
  {

  	struct ucb1x00_ts *ts = input_get_drvdata(idev);

  	unsigned long flags = 0;

  	int ret = 0;

  	BUG_ON(ts->rtask);

  	if (machine_is_collie())
  		flags = IRQF_TRIGGER_RISING;
  	else
  		flags = IRQF_TRIGGER_FALLING;
  
  	ts->irq_disabled = 0;

  	init_waitqueue_head(&ts->irq_wait);

  	ret = request_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ucb1x00_ts_irq,
  			  flags, "ucb1x00-ts", 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 {

  		free_irq(ts->ucb->irq_base + 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);

  	free_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ts);

  	ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
  	ucb1x00_disable(ts->ucb);

  }

  
  /*
   * 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;

  	spin_lock_init(&ts->irq_lock);

  	idev->name       = "Touchscreen panel";

  	idev->id.product = ts->ucb->id;

  	idev->open       = ucb1x00_ts_open;
  	idev->close      = ucb1x00_ts_close;

  	idev->dev.parent = &ts->ucb->dev;

  	idev->evbit[0]   = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
  	idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);

  	input_set_drvdata(idev, ts);

  	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);
  
  	input_set_abs_params(idev, ABS_X, 0, ts->x_res, 0, 0);
  	input_set_abs_params(idev, ABS_Y, 0, ts->y_res, 0, 0);
  	input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);

  	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,

  };
  
  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");