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Commit 1936d590 authored by Imre Deak's avatar Imre Deak Committed by Dmitry Torokhov
Browse files

Input: ads7846 - switch to using hrtimer 



Use hrtimer instead of the normal timer, since it provides better
sampling resolution. This will:

 - avoid a problem where we have a 1 jiffy poll period and
   dynamic tick on
 - utilize high resolution HW clocks when they are added to
   the hrtimer framework

Signed-off-by: default avatarImre Deak <imre.deak@solidboot.com>
Signed-off-by: default avatarJuha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent de2defd9

drivers/input/touchscreen/ads7846.c

+15 −11
Original line number Diff line number Diff line
@@ -54,7 +54,8 @@ 
 * files.

 */



#define	TS_POLL_PERIOD	msecs_to_jiffies(10)

#define TS_POLL_DELAY	(1 * 1000000)	/* ns delay before the first sample */

#define TS_POLL_PERIOD	(5 * 1000000)	/* ns delay between samples */



/* this driver doesn't aim at the peak continuous sample rate */

#define	SAMPLE_BITS	(8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
@@ -99,7 +100,7 @@ struct ads7846 { 
	u16			debounce_rep;



	spinlock_t		lock;

	struct timer_list	timer;		/* P: lock */

	struct hrtimer		timer;

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

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

// FIXME remove "irq_disabled"
@@ -408,9 +409,11 @@ static void ads7846_rx(void *ads) 


	/* Sample found inconsistent by debouncing or pressure is beyond

	 * the maximum. Don't report it to user space, repeat at least

	* once more the measurement */

	 * once more the measurement

	 */

	if (ts->tc.ignore || Rt > ts->pressure_max) {

		mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);

		hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),

			      HRTIMER_REL);

		return;

	}
@@ -452,7 +455,7 @@ static void ads7846_rx(void *ads) 
	spin_lock_irqsave(&ts->lock, flags);



	ts->pendown = (Rt != 0);

	mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);

	hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), HRTIMER_REL);



	spin_unlock_irqrestore(&ts->lock, flags);

}
@@ -543,9 +546,9 @@ static void ads7846_rx_val(void *ads) 
				status);

}



static void ads7846_timer(unsigned long handle)

static int ads7846_timer(struct hrtimer *handle)

{

	struct ads7846	*ts = (void *)handle;

	struct ads7846	*ts = container_of(handle, struct ads7846, timer);

	int		status = 0;



	spin_lock_irq(&ts->lock);
@@ -567,6 +570,7 @@ static void ads7846_timer(unsigned long handle) 
	}



	spin_unlock_irq(&ts->lock);

	return HRTIMER_NORESTART;

}



static irqreturn_t ads7846_irq(int irq, void *handle)
@@ -585,7 +589,8 @@ static irqreturn_t ads7846_irq(int irq, void *handle) 
			ts->irq_disabled = 1;

			disable_irq(ts->spi->irq);

			ts->pending = 1;

			mod_timer(&ts->timer, jiffies);

			hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),

					HRTIMER_REL);

		}

	}

	spin_unlock_irqrestore(&ts->lock, flags);
@@ -719,8 +724,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) 
	ts->spi = spi;

	ts->input = input_dev;



	init_timer(&ts->timer);

	ts->timer.data = (unsigned long) ts;

	hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_REL);

	ts->timer.function = ads7846_timer;



	spin_lock_init(&ts->lock);