Input: ads7846 - improve filtering for thumb press accuracy

Providing more accurate coordinates for thumb press requires additional
steps in the filtering logic:

- Ignore samples found invalid by the debouncing logic, or the ones that
  have out of bound pressure value.
- Add a parameter to repeat debouncing, so that more then two consecutive
  good readings are required for a valid sample.

Signed-off-by: Imre Deak <imre.deak@nokia.com>
Acked-by: Juha Yrjola <juha.yrjola@nokia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 4 insertions, 2 deletions

diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h
index d8823e237e0b..adb3dafd33e9 100644
--- a/include/linux/spi/ads7846.h
+++ b/include/linux/spi/ads7846.h
@@ -15,9 +15,11 @@ struct ads7846_platform_data {
         u16     y_min, y_max;
         u16     pressure_min, pressure_max;
 
-        u16     debounce_max;           /* max number of readings per sample */
+        u16     debounce_max;           /* max number of additional readings
+                                         * per sample */
         u16     debounce_tol;           /* tolerance used for filtering */
-
+        u16     debounce_rep;           /* additional consecutive good readings
+                                         * required after the first two */
         int     (*get_pendown_state)(void);
 };