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-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 103ee6ad299..96581d08774 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -107,6 +107,8 @@ struct ads7846 {
u16 debounce_tol;
u16 debounce_rep;
+ u16 penirq_recheck_delay_usecs;
+
spinlock_t lock;
struct hrtimer timer;
unsigned pendown:1; /* P: lock */
@@ -553,6 +555,15 @@ static void ads7846_rx(void *ads)
return;
}
+ /* Maybe check the pendown state before reporting. This discards
+ * false readings when the pen is lifted.
+ */
+ if (ts->penirq_recheck_delay_usecs) {
+ udelay(ts->penirq_recheck_delay_usecs);
+ if (!ts->get_pendown_state())
+ Rt = 0;
+ }
+
/* NOTE: We can't rely on the pressure to determine the pen down
* state, even this controller has a pressure sensor. The pressure
* 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)
ts->filter = ads7846_no_filter;
ts->get_pendown_state = pdata->get_pendown_state;
+ if (pdata->penirq_recheck_delay_usecs)
+ ts->penirq_recheck_delay_usecs =
+ pdata->penirq_recheck_delay_usecs;
+
snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
input_dev->name = "ADS784x Touchscreen";