[PATCH] appletouch: Improved finger detection

[Jeremy Huddleston <jeremyhu@xxxxxxxxxxxxxxx>]

The appletouch driver is prone to reporting multiple fingers when only  
one is
pressing.  The appletouch driver queries an array of pressure sensors  
and
counts local maxima in pressure to determine the number of fingers.   
It just
does this on the raw values, so a data stream like:

0 100 250 300 299 300 250 100 0

actually registers as 2 fingers.

This patch updates the logic to ignore small dips in pressure that are  
less
than the threshold.

Signed-off-by: Jeremy Huddleston <jeremyhu@xxxxxxxxxxxxxxx>

diff --git a/drivers/input/mouse/appletouch.c b/drivers/input/mouse/ 
appletouch.c
index 454b961..9bb42f6 100644
--- a/drivers/input/mouse/appletouch.c
+++ b/drivers/input/mouse/appletouch.c
@@ -349,7 +349,7 @@ static int atp_calculate_abs(int *xy_sensors, int  
nb_sensors, int fact,
 		    (!is_increasing && xy_sensors[i - 1] < xy_sensors[i])) {
 			(*fingers)++;
 			is_increasing = 1;
-		} else if (i > 0 && xy_sensors[i - 1] >= xy_sensors[i]) {
+		} else if (i > 0 && (xy_sensors[i - 1] - xy_sensors[i] >  
threshold)) {
 			is_increasing = 0;
 		}

Attachment: appletouch.patch
Description: Binary data