[PATCH] Input: synaptics - add support for reporting x/y resolution

[Tero Saarni <tero.saarni@gmail.com>]

Synaptics uses anisotropic coordinate system.  On some wide touchpads
vertical resolution can be twice as high as horizontal leading to
unequal sensitivity.  To allow compensation add support for reading
the resolution.

Signed-off-by: Tero Saarni <tero.saarni@gmail.com>
---

This is revision 2 of the patch.

Added more validity checks for resolution query, according to 
chapter 3.5.1 in Synaptics TouchPad Interfacing Guide [1].

[1] http://www.synaptics.com/sites/default/files/ACF126.pdf


 drivers/input/mouse/synaptics.c |   27 +++++++++++++++++++++++++++
 drivers/input/mouse/synaptics.h |    2 ++
 include/linux/input.h           |    2 ++
 3 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index f3e4f7b..1afbb49 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -180,6 +180,29 @@ static int synaptics_identify(struct psmouse *psmouse)
 	return -1;
 }
 
+/*
+ * Read touchpad resolution
+ * Resolution is left zero if touchpad does not support the query
+ */
+static int synaptics_resolution(struct psmouse *psmouse)
+{
+	struct synaptics_data *priv = psmouse->private;
+	unsigned char res[3];
+
+	if (SYN_ID_MAJOR(priv->identity) < 4)
+		return 0;
+
+	if (synaptics_send_cmd(psmouse, SYN_QUE_RESOLUTION, res))
+		return 0;
+
+	if ((res[0] != 0) && (res[1] & 0x80) && (res[2] != 0)) {
+		priv->x_res = res[0];
+		priv->y_res = res[2];
+	}
+
+	return 0;
+}
+
 static int synaptics_query_hardware(struct psmouse *psmouse)
 {
 	if (synaptics_identify(psmouse))
@@ -188,6 +211,8 @@ static int synaptics_query_hardware(struct psmouse *psmouse)
 		return -1;
 	if (synaptics_capability(psmouse))
 		return -1;
+	if (synaptics_resolution(psmouse))
+		return -1;
 
 	return 0;
 }
@@ -534,6 +559,8 @@ static void set_input_params(struct input_dev *dev, struct synaptics_data *priv)
 	set_bit(EV_ABS, dev->evbit);
 	input_set_abs_params(dev, ABS_X, XMIN_NOMINAL, XMAX_NOMINAL, 0, 0);
 	input_set_abs_params(dev, ABS_Y, YMIN_NOMINAL, YMAX_NOMINAL, 0, 0);
+	input_set_abs_params(dev, ABS_RESX, 0, priv->x_res, 0, 0);
+	input_set_abs_params(dev, ABS_RESY, 0, priv->y_res, 0, 0);
 	input_set_abs_params(dev, ABS_PRESSURE, 0, 255, 0, 0);
 	set_bit(ABS_TOOL_WIDTH, dev->absbit);
 
diff --git a/drivers/input/mouse/synaptics.h b/drivers/input/mouse/synaptics.h
index 02aa4cf..e9a69c9 100644
--- a/drivers/input/mouse/synaptics.h
+++ b/drivers/input/mouse/synaptics.h
@@ -101,6 +101,8 @@ struct synaptics_data {
 	unsigned char pkt_type;			/* packet type - old, new, etc */
 	unsigned char mode;			/* current mode byte */
 	int scroll;
+	int x_res;                              /* x resolution in units/mm */
+	int y_res;                              /* y resolution in units/mm */
 };
 
 int synaptics_detect(struct psmouse *psmouse, int set_properties);
diff --git a/include/linux/input.h b/include/linux/input.h
index 0e6ff5d..029cece 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -645,6 +645,8 @@ struct input_absinfo {
 #define ABS_TILT_Y		0x1b
 #define ABS_TOOL_WIDTH		0x1c
 #define ABS_VOLUME		0x20
+#define ABS_RESX		0x26
+#define ABS_RESY		0x27
 #define ABS_MISC		0x28
 
 #define ABS_MT_TOUCH_MAJOR	0x30	/* Major axis of touching ellipse */
-- 
1.6.0.4