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authorSemih Hazar <semih.hazar@indefia.com>2007-07-18 00:36:04 -0400
committerDmitry Torokhov <dtor@insightbb.com>2007-07-18 00:36:04 -0400
commit1d25891f3241103d14ea78236504474a138b8ada (patch)
treecaeef0ea5f41eae2a005b6eab642e823d4791a0f /drivers/input
parente4f48861993294c27849076741eb0c090482560b (diff)
Input: ads7846 - re-check pendown status before reporting events
Pendown status from the PENIRQ pin is currently read only at the beginning of a sample set. If the pen is lifted just after sampling has began then sampled values become wrong. This patch adds an optional platform penirq_recheck_delay attribute. If non-zero, samples are only reported to the input subsystem if PENIRQ is still active that long after the samples taken. Signed-off-by: Semih Hazar <semih.hazar@indefia.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input')
-rw-r--r--drivers/input/touchscreen/ads7846.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 103ee6ad299e..96581d08774f 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -107,6 +107,8 @@ struct ads7846 {
107 u16 debounce_tol; 107 u16 debounce_tol;
108 u16 debounce_rep; 108 u16 debounce_rep;
109 109
110 u16 penirq_recheck_delay_usecs;
111
110 spinlock_t lock; 112 spinlock_t lock;
111 struct hrtimer timer; 113 struct hrtimer timer;
112 unsigned pendown:1; /* P: lock */ 114 unsigned pendown:1; /* P: lock */
@@ -553,6 +555,15 @@ static void ads7846_rx(void *ads)
553 return; 555 return;
554 } 556 }
555 557
558 /* Maybe check the pendown state before reporting. This discards
559 * false readings when the pen is lifted.
560 */
561 if (ts->penirq_recheck_delay_usecs) {
562 udelay(ts->penirq_recheck_delay_usecs);
563 if (!ts->get_pendown_state())
564 Rt = 0;
565 }
566
556 /* NOTE: We can't rely on the pressure to determine the pen down 567 /* NOTE: We can't rely on the pressure to determine the pen down
557 * state, even this controller has a pressure sensor. The pressure 568 * state, even this controller has a pressure sensor. The pressure
558 * value can fluctuate for quite a while after lifting the pen and 569 * value can fluctuate for quite a while after lifting the pen and
@@ -896,6 +907,10 @@ static int __devinit ads7846_probe(struct spi_device *spi)
896 ts->filter = ads7846_no_filter; 907 ts->filter = ads7846_no_filter;
897 ts->get_pendown_state = pdata->get_pendown_state; 908 ts->get_pendown_state = pdata->get_pendown_state;
898 909
910 if (pdata->penirq_recheck_delay_usecs)
911 ts->penirq_recheck_delay_usecs =
912 pdata->penirq_recheck_delay_usecs;
913
899 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); 914 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
900 915
901 input_dev->name = "ADS784x Touchscreen"; 916 input_dev->name = "ADS784x Touchscreen";