[PATCH 5/5] input: wacom: Add a quirk for lowres Bamboo devices

[Henrik Rydberg]

The Bamboo Touch reports a sub-screen resolution of 480x320.
The signal-to-noise ratio is only about 100, so filtering is
needed in order to reduce the jitter to a usable level. However,
the low resolution leads to round-off errors in the EWMA filter,
resulting in extremely jerky pointer motion. This patch explicitly
sets a higher resolution for those devices, and tells this to
the completion handler via a low-resolution quirk.

Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>
---
 drivers/input/tablet/wacom_wac.c |   15 +++++++++++++++
 drivers/input/tablet/wacom_wac.h |    1 +
 2 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/drivers/input/tablet/wacom_wac.c b/drivers/input/tablet/wacom_wac.c
index 78e5345..fd2d46a 100644
--- a/drivers/input/tablet/wacom_wac.c
+++ b/drivers/input/tablet/wacom_wac.c
@@ -858,6 +858,7 @@ static int wacom_tpc_irq(struct wacom_wac *wacom, size_t len)
 static int wacom_bpt_irq(struct wacom_wac *wacom, size_t len)
 {
 	static int trkid;
+	struct wacom_features *features = &wacom->features;
 	struct input_dev *input = wacom->input;
 	unsigned char *data = wacom->data;
 	int sp = 0, sx = 0, sy = 0, count = 0;
@@ -872,6 +873,10 @@ static int wacom_bpt_irq(struct wacom_wac *wacom, size_t len)
 		if (p) {
 			int x = get_unaligned_be16(&data[9 * i + 3]) & 0x7ff;
 			int y = get_unaligned_be16(&data[9 * i + 5]) & 0x7ff;
+			if (features->quirks & WACOM_QUIRK_BBTOUCH_LOWRES) {
+				x <<= 5;
+				y <<= 5;
+			}
 			input_report_abs(input, ABS_MT_PRESSURE, p);
 			input_report_abs(input, ABS_MT_POSITION_X, x);
 			input_report_abs(input, ABS_MT_POSITION_Y, y);
@@ -1007,6 +1012,16 @@ void wacom_setup_device_quirks(struct wacom_features *features)
 	if (features->type == TABLETPC || features->type == TABLETPC2FG ||
 	    features->type == BAMBOO_PT)
 		features->quirks |= WACOM_QUIRK_MULTI_INPUT;
+
+	/* quirks for bamboo touch */
+	if (features->x_max == 480 && features->y_max == 320) {
+		features->x_max = 15360;
+		features->y_max = 10240;
+		features->x_fuzz = 128;
+		features->y_fuzz = 128;
+		features->pressure_fuzz = 16;
+		features->quirks |= WACOM_QUIRK_BBTOUCH_LOWRES;
+	}
 }
 
 void wacom_setup_input_capabilities(struct input_dev *input_dev,
diff --git a/drivers/input/tablet/wacom_wac.h b/drivers/input/tablet/wacom_wac.h
index 1284f33..b9de134 100644
--- a/drivers/input/tablet/wacom_wac.h
+++ b/drivers/input/tablet/wacom_wac.h
@@ -43,6 +43,7 @@
 
 /* device quirks */
 #define WACOM_QUIRK_MULTI_INPUT		0x0001
+#define WACOM_QUIRK_BBTOUCH_LOWRES	0x0002
 
 enum {
 	PENPARTNER = 0,
-- 
1.7.1

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