hid: egalax: Add event filtering
Use estimated signal-to-noise ratios to reduce noise and limit the
amount of events emitted.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Stephane Chatty <chatty@enac.fr>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
diff --git a/drivers/hid/hid-egalax.c b/drivers/hid/hid-egalax.c
index aac8a63..66b2c5d 100644
--- a/drivers/hid/hid-egalax.c
+++ b/drivers/hid/hid-egalax.c
@@ -25,6 +25,10 @@
#include "hid-ids.h"
+/* estimated signal-to-noise ratios */
+#define SN_MOVE 4096
+#define SN_PRESSURE 32
+
struct egalax_data {
__u16 x, y, z;
__u8 id;
@@ -57,17 +61,17 @@
field->logical_maximum = 32760;
hid_map_usage(hi, usage, bit, max,
EV_ABS, ABS_MT_POSITION_X);
- set_abs(input, ABS_MT_POSITION_X, field, 0);
+ set_abs(input, ABS_MT_POSITION_X, field, SN_MOVE);
/* touchscreen emulation */
- set_abs(input, ABS_X, field, 0);
+ set_abs(input, ABS_X, field, SN_MOVE);
return 1;
case HID_GD_Y:
field->logical_maximum = 32760;
hid_map_usage(hi, usage, bit, max,
EV_ABS, ABS_MT_POSITION_Y);
- set_abs(input, ABS_MT_POSITION_Y, field, 0);
+ set_abs(input, ABS_MT_POSITION_Y, field, SN_MOVE);
/* touchscreen emulation */
- set_abs(input, ABS_Y, field, 0);
+ set_abs(input, ABS_Y, field, SN_MOVE);
return 1;
}
return 0;
@@ -93,9 +97,9 @@
field->logical_minimum = 0;
hid_map_usage(hi, usage, bit, max,
EV_ABS, ABS_MT_PRESSURE);
- set_abs(input, ABS_MT_PRESSURE, field, 0);
+ set_abs(input, ABS_MT_PRESSURE, field, SN_PRESSURE);
/* touchscreen emulation */
- set_abs(input, ABS_PRESSURE, field, 0);
+ set_abs(input, ABS_PRESSURE, field, SN_PRESSURE);
return 1;
}
return 0;