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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: Imre Deak <imre.deak@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
Imre Deak 2007-01-18 00:45:31 -05:00 committed by Dmitry Torokhov
parent de2defd96d
commit 1936d590a9
1 changed files with 15 additions and 11 deletions
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26
drivers/input/touchscreen/ads7846.c
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@ -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"
@ -407,10 +408,12 @@ static void ads7846_rx(void *ads)
Rt = 0;
/* 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 */
* the maximum. Don't report it to user space, repeat at least
* 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);