[PATCH v3] input : wacom_w8001 - report resolution to userland

[Ping Cheng <pinglinux@gmail.com>]

Serial devices send both pen and touch data through the same logical
port. Since we scaled touch to pen maximum, we use pen resolution
for touch as well here.

This is under the assumption that pen and touch share the same physical
surface. In the case when a small physical dimensional difference occurs
between pen and touch, we assume the tolerance for touch point precision
is higher than pen and the difference is within touch point tolerance.

A per-MT tool based resolution mechanism should be introduced if the
above assumption does not hold true for the pen and touch devices any
more. A good candidate to resolve this issue without introducing design
change could be to report touch resolution through ABS_MT_POSITION_X/Y.

This version corrected an oversimplified if statement in v2.

Signed-off-by: Ping Cheng <pingc@wacom.com>
---
 drivers/input/touchscreen/wacom_w8001.c |   20 +++++++++++++++-----
 1 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/wacom_w8001.c b/drivers/input/touchscreen/wacom_w8001.c
index 5cb8449..68dcca0 100644
--- a/drivers/input/touchscreen/wacom_w8001.c
+++ b/drivers/input/touchscreen/wacom_w8001.c
@@ -51,6 +51,10 @@ MODULE_LICENSE("GPL");
 #define W8001_PKTLEN_TPCCTL	11	/* control packet */
 #define W8001_PKTLEN_TOUCH2FG	13
 
+/* resolution in points/mm */
+#define W8001_PEN_RESOLUTION    100
+#define W8001_TOUCH_RESOLUTION  10
+
 struct w8001_coord {
 	u8 rdy;
 	u8 tsw;
@@ -198,7 +202,7 @@ static void parse_touchquery(u8 *data, struct w8001_touch_query *query)
 		query->y = 1024;
 		if (query->panel_res)
 			query->x = query->y = (1 << query->panel_res);
-		query->panel_res = 10;
+		query->panel_res = W8001_TOUCH_RESOLUTION;
 	}
 }
 
@@ -394,6 +398,8 @@ static int w8001_setup(struct w8001 *w8001)
 
 		input_set_abs_params(dev, ABS_X, 0, coord.x, 0, 0);
 		input_set_abs_params(dev, ABS_Y, 0, coord.y, 0, 0);
+		input_abs_set_res(dev, ABS_X, W8001_PEN_RESOLUTION);
+		input_abs_set_res(dev, ABS_Y, W8001_PEN_RESOLUTION);
 		input_set_abs_params(dev, ABS_PRESSURE, 0, coord.pen_pressure, 0, 0);
 		if (coord.tilt_x && coord.tilt_y) {
 			input_set_abs_params(dev, ABS_TILT_X, 0, coord.tilt_x, 0, 0);
@@ -418,15 +424,19 @@ static int w8001_setup(struct w8001 *w8001)
 		w8001->max_touch_x = touch.x;
 		w8001->max_touch_y = touch.y;
 
-		/* scale to pen maximum */
+		/* pen supported */
 		if (w8001->max_pen_x && w8001->max_pen_y) {
+			/* scale to pen maximum */
 			touch.x = w8001->max_pen_x;
 			touch.y = w8001->max_pen_y;
+		} else { /* touch only */
+			/* set axes with touch data */
+			input_set_abs_params(dev, ABS_X, 0, touch.x, 0, 0);
+			input_set_abs_params(dev, ABS_Y, 0, touch.y, 0, 0);
+			input_abs_set_res(dev, ABS_X, touch.panel_res);
+			input_abs_set_res(dev, ABS_Y, touch.panel_res);
 		}
 
-		input_set_abs_params(dev, ABS_X, 0, touch.x, 0, 0);
-		input_set_abs_params(dev, ABS_Y, 0, touch.y, 0, 0);
-
 		switch (touch.sensor_id) {
 		case 0:
 		case 2:
-- 
1.7.3.5