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Commit 7de90a8c authored by Imre Deak's avatar Imre Deak Committed by Dmitry Torokhov
Browse files

Input: ads7846 - miscellaneous fixes 



- Add disable attribute to support device locking mode where
  unintentional touch event shouldn't wake up the system;
- Update comments;
- Add missing spin_lock_init;
- Do device resume with the lock held;
- Do cleanup calls / free memory in the reverse order of initialization.

Signed-off-by: default avatarImre Deak <imre.deak@nokia.com>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent c4febb94

drivers/input/touchscreen/ads7846.c

+114 −30
Original line number Diff line number Diff line
@@ -2,6 +2,8 @@ 
 * ADS7846 based touchscreen and sensor driver

 *

 * Copyright (c) 2005 David Brownell

 * Copyright (c) 2006 Nokia Corporation

 * Various changes: Imre Deak <imre.deak@nokia.com>

 *

 * Using code from:

 *  - corgi_ts.c
@@ -34,17 +36,25 @@ 




/*

 * This code has been lightly tested on an ads7846.

 * This code has been tested on an ads7846 / N770 device.

 * Support for ads7843 and ads7845 has only been stubbed in.

 *

 * Not yet done:  investigate the values reported.  Are x/y/pressure

 * event values sane enough for X11?  How accurate are the temperature

 * and voltage readings?  (System-specific calibration should support

 * Not yet done:  How accurate are the temperature and voltage

 * readings? (System-specific calibration should support

 * accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.)

 *

 * IRQ handling needs a workaround because of a shortcoming in handling

 * edge triggered IRQs on some platforms like the OMAP1/2. These

 * platforms don't handle the ARM lazy IRQ disabling properly, thus we

 * have to maintain our own SW IRQ disabled status. This should be

 * removed as soon as the affected platform's IRQ handling is fixed.

 *

 * app note sbaa036 talks in more detail about accurate sampling...

 * that ought to help in situations like LCDs inducing noise (which

 * can also be helped by using synch signals) and more generally.

 * This driver tries to utilize the measures described in the app

 * note. The strength of filtering can be set in the board-* specific

 * files.

 */



#define	TS_POLL_PERIOD	msecs_to_jiffies(10)
@@ -91,6 +101,7 @@ struct ads7846 { 
	unsigned		pending:1;	/* P: lock */

// FIXME remove "irq_disabled"

	unsigned		irq_disabled:1;	/* P: lock */

	unsigned		disabled:1;

};



/* leave chip selected when we're done, for quicker re-select? */
@@ -161,6 +172,9 @@ struct ser_req { 
	struct spi_transfer	xfer[6];

};



static void ads7846_enable(struct ads7846 *ts);

static void ads7846_disable(struct ads7846 *ts);



static int ads7846_read12_ser(struct device *dev, unsigned command)

{

	struct spi_device	*spi = to_spi_device(dev);
@@ -257,6 +271,37 @@ static ssize_t ads7846_pen_down_show(struct device *dev, 


static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);



static ssize_t ads7846_disable_show(struct device *dev,

				     struct device_attribute *attr, char *buf)

{

	struct ads7846	*ts = dev_get_drvdata(dev);



	return sprintf(buf, "%u\n", ts->disabled);

}



static ssize_t ads7846_disable_store(struct device *dev,

				     struct device_attribute *attr,

				     const char *buf, size_t count)

{

	struct ads7846 *ts = dev_get_drvdata(dev);

	char *endp;

	int i;



	i = simple_strtoul(buf, &endp, 10);

	spin_lock_irq(&ts->lock);



	if (i)

		ads7846_disable(ts);

	else

		ads7846_enable(ts);



	spin_unlock_irq(&ts->lock);



	return count;

}



static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);



/*--------------------------------------------------------------------------*/



/*
@@ -396,12 +441,9 @@ static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs) 
{

	struct ads7846 *ts = handle;

	unsigned long flags;

	int r = IRQ_HANDLED;



	spin_lock_irqsave(&ts->lock, flags);

	if (ts->irq_disabled)

		r = IRQ_HANDLED;

	else {

	if (likely(!ts->irq_disabled && !ts->disabled)) {

		if (!ts->irq_disabled) {

			/* REVISIT irq logic for many ARM chips has cloned a

			 * bug wherein disabling an irq in its handler won't
@@ -419,20 +461,17 @@ static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs) 
		}

	}

	spin_unlock_irqrestore(&ts->lock, flags);

	return r;



	return IRQ_HANDLED;

}



/*--------------------------------------------------------------------------*/



static int

ads7846_suspend(struct spi_device *spi, pm_message_t message)

/* Must be called with ts->lock held */

static void ads7846_disable(struct ads7846 *ts)

{

	struct ads7846 *ts = dev_get_drvdata(&spi->dev);

	unsigned long	flags;



	spin_lock_irqsave(&ts->lock, flags);



	spi->dev.power.power_state = message;

	if (ts->disabled)

		return;



	/* are we waiting for IRQ, or polling? */

	if (!ts->pendown) {
@@ -448,9 +487,9 @@ ads7846_suspend(struct spi_device *spi, pm_message_t message) 
			mod_timer(&ts->timer, jiffies);



		while (ts->pendown || ts->pending) {

			spin_unlock_irqrestore(&ts->lock, flags);

			spin_unlock_irq(&ts->lock);

			msleep(1);

			spin_lock_irqsave(&ts->lock, flags);

			spin_lock_irq(&ts->lock);

		}

	}
@@ -458,17 +497,46 @@ ads7846_suspend(struct spi_device *spi, pm_message_t message) 
	 * leave it that way after every request

	 */



	spin_unlock_irqrestore(&ts->lock, flags);

	ts->disabled = 1;

}



/* Must be called with ts->lock held */

static void ads7846_enable(struct ads7846 *ts)

{

	if (!ts->disabled)

		return;



	ts->disabled = 0;

	ts->irq_disabled = 0;

	enable_irq(ts->spi->irq);

}



static int ads7846_suspend(struct spi_device *spi, pm_message_t message)

{

	struct ads7846 *ts = dev_get_drvdata(&spi->dev);



	spin_lock_irq(&ts->lock);



	spi->dev.power.power_state = message;

	ads7846_disable(ts);



	spin_unlock_irq(&ts->lock);



	return 0;



}



static int ads7846_resume(struct spi_device *spi)

{

	struct ads7846 *ts = dev_get_drvdata(&spi->dev);



	ts->irq_disabled = 0;

	enable_irq(ts->spi->irq);

	spin_lock_irq(&ts->lock);



	spi->dev.power.power_state = PMSG_ON;

	ads7846_enable(ts);



	spin_unlock_irq(&ts->lock);



	return 0;

}
@@ -521,6 +589,8 @@ static int __devinit ads7846_probe(struct spi_device *spi) 
	ts->timer.data = (unsigned long) ts;

	ts->timer.function = ads7846_timer;



	spin_lock_init(&ts->lock);



	ts->model = pdata->model ? : 7846;

	ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;

	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
@@ -671,13 +741,25 @@ static int __devinit ads7846_probe(struct spi_device *spi) 


	device_create_file(&spi->dev, &dev_attr_pen_down);



	device_create_file(&spi->dev, &dev_attr_disable);



	err = input_register_device(input_dev);

	if (err)

		goto err_free_irq;

		goto err_remove_attr;



	return 0;



 err_free_irq:

 err_remove_attr:

	device_remove_file(&spi->dev, &dev_attr_disable);

	device_remove_file(&spi->dev, &dev_attr_pen_down);

	if (ts->model == 7846) {

		device_remove_file(&spi->dev, &dev_attr_temp1);

		device_remove_file(&spi->dev, &dev_attr_temp0);

	}

	if (ts->model != 7845)

		device_remove_file(&spi->dev, &dev_attr_vbatt);

	device_remove_file(&spi->dev, &dev_attr_vaux);



	free_irq(spi->irq, ts);

 err_free_mem:

	input_free_device(input_dev);
@@ -689,22 +771,24 @@ static int __devexit ads7846_remove(struct spi_device *spi) 
{

	struct ads7846		*ts = dev_get_drvdata(&spi->dev);



	input_unregister_device(ts->input);



	ads7846_suspend(spi, PMSG_SUSPEND);

	free_irq(ts->spi->irq, ts);

	if (ts->irq_disabled)

		enable_irq(ts->spi->irq);



	device_remove_file(&spi->dev, &dev_attr_disable);

	device_remove_file(&spi->dev, &dev_attr_pen_down);



	if (ts->model == 7846) {

		device_remove_file(&spi->dev, &dev_attr_temp0);

		device_remove_file(&spi->dev, &dev_attr_temp1);

		device_remove_file(&spi->dev, &dev_attr_temp0);

	}

	if (ts->model != 7845)

		device_remove_file(&spi->dev, &dev_attr_vbatt);

	device_remove_file(&spi->dev, &dev_attr_vaux);



	input_unregister_device(ts->input);

	free_irq(ts->spi->irq, ts);

	if (ts->irq_disabled)

		enable_irq(ts->spi->irq);



	kfree(ts);



	dev_dbg(&spi->dev, "unregistered touchscreen\n");