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>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h
index a44fa7a02bd9..334d31411629 100644
--- a/include/linux/spi/ads7846.h
+++ b/include/linux/spi/ads7846.h
@@ -24,6 +24,12 @@ struct ads7846_platform_data {
          */
         u16     settle_delay_usecs;
 
+        /* If set to non-zero, after samples are taken this delay is applied
+         * and penirq is rechecked, to help avoid false events.  This value
+         * is affected by the material used to build the touch layer.
+         */
+        u16     penirq_recheck_delay_usecs;
+
         u16     x_plate_ohms;
         u16     y_plate_ohms;