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>
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index c34e59b..d983cc5 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -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 @@
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 @@
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 @@
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 @@
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 @@
}
spin_unlock_irq(&ts->lock);
+ return HRTIMER_NORESTART;
}
static irqreturn_t ads7846_irq(int irq, void *handle)
@@ -585,7 +589,8 @@
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 @@
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);