[PATCH 4/4] Input: synaptics - emit multitouch data

["Henrik Rydberg" <rydberg@euromail.se>]

In multitouch mode, two data packets are sent from the device.  Due to
limitations in the hardware detection mechanism, individual contacts
cannot be reliably extracted. However, the bounding rectangle of the
individual contacts can be accurately reproduced. This patch emits the
MT data as rectangle corners, allowing userspace to track and produce
appropriate gestures. The number of fingers are still reported as before.
The INPUT_PROP_SEMI_MT quirk is set to signal this special behavior.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
---
 drivers/input/mouse/synaptics.c |   42 ++++++++++++++++++++++++++++++++++++++-
 1 files changed, 41 insertions(+), 1 deletions(-)

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index 01302db..1ae5c29 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -25,7 +25,7 @@
 
 #include <linux/module.h>
 #include <linux/dmi.h>
-#include <linux/input.h>
+#include <linux/input/mt.h>
 #include <linux/serio.h>
 #include <linux/libps2.h>
 #include <linux/slab.h>
@@ -489,6 +489,34 @@ static int synaptics_parse_hw_state(unsigned char buf[], struct synaptics_data *
 	return 0;
 }
 
+static void set_slot(struct input_dev *dev, int slot, bool active, int x, int y)
+{
+	input_mt_slot(dev, slot);
+	input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
+	if (active) {
+		input_report_abs(dev, ABS_MT_POSITION_X, x);
+		input_report_abs(dev, ABS_MT_POSITION_Y,
+				 YMAX_NOMINAL + YMIN_NOMINAL - y);
+	}
+}
+
+static void synaptics_report_mt_data(struct input_dev *dev,
+				     const struct synaptics_hw_state *a,
+				     const struct synaptics_hw_state *b,
+				     int num_fingers)
+{
+	if (num_fingers >= 2) {
+		set_slot(dev, 0, true, min(a->x, b->x), min(a->y, b->y));
+		set_slot(dev, 1, true, max(a->x, b->x), max(a->y, b->y));
+	} else if (num_fingers == 1) {
+		set_slot(dev, 0, true, a->x, a->y);
+		set_slot(dev, 1, false, 0, 0);
+	} else {
+		set_slot(dev, 0, false, 0, 0);
+		set_slot(dev, 1, false, 0, 0);
+	}
+}
+
 /*
  *  called for each full received packet from the touchpad
  */
@@ -551,6 +579,9 @@ static void synaptics_process_packet(struct psmouse *psmouse)
 		finger_width = 0;
 	}
 
+	if (priv->multitouch)
+		synaptics_report_mt_data(dev, &hw, &priv->mt, num_fingers);
+
 	/* Post events
 	 * BTN_TOUCH has to be first as mousedev relies on it when doing
 	 * absolute -> relative conversion
@@ -662,6 +693,7 @@ static void set_input_params(struct input_dev *dev, struct synaptics_data *priv)
 	int i;
 
 	__set_bit(INPUT_PROP_POINTER, dev->propbit);
+	__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
 
 	__set_bit(EV_ABS, dev->evbit);
 	input_set_abs_params(dev, ABS_X,
@@ -670,6 +702,14 @@ static void set_input_params(struct input_dev *dev, struct synaptics_data *priv)
 			     YMIN_NOMINAL, priv->y_max ?: YMAX_NOMINAL, 0, 0);
 	input_set_abs_params(dev, ABS_PRESSURE, 0, 255, 0, 0);
 
+	if (priv->multitouch) {
+		input_mt_init_slots(dev, 2);
+		input_set_abs_params(dev, ABS_MT_POSITION_X, XMIN_NOMINAL,
+				     priv->x_max ?: XMAX_NOMINAL, 0, 0);
+		input_set_abs_params(dev, ABS_MT_POSITION_Y, YMIN_NOMINAL,
+				     priv->y_max ?: YMAX_NOMINAL, 0, 0);
+	}
+
 	if (SYN_CAP_PALMDETECT(priv->capabilities))
 		input_set_abs_params(dev, ABS_TOOL_WIDTH, 0, 15, 0, 0);
 
-- 
1.7.2.3