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Subject[PATCH 5/6] hid: egalax: Add event filtering
Date
Use estimated signal-to-noise ratios to reduce noise and limit the
amount of events emitted.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
---
drivers/hid/hid-egalax.c | 16 ++++++++++------
1 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/hid/hid-egalax.c b/drivers/hid/hid-egalax.c
index 2aba897..b21e7dc 100644
--- a/drivers/hid/hid-egalax.c
+++ b/drivers/hid/hid-egalax.c
@@ -27,6 +27,10 @@ MODULE_LICENSE("GPL");

#define MAX_EVENTS 120

+/* estimated signal-to-noise ratios */
+#define SN_MOVE 1024
+#define SN_PRESSURE 32
+
struct egalax_data {
__u16 x, y, z;
__u8 id;
@@ -59,17 +63,17 @@ static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
field->logical_maximum <<= 3;
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 <<= 3;
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;
@@ -96,9 +100,9 @@ static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
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;
--
1.7.1


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