Make bcm5974 report raw multi-touch (MT) data in the form of ABS_MT

events.  The module parameter (nomt) may be used to turn off the effect of
this patch.

The module paremeter was added because all MT events bypass the input
filtering and get sent directly to the X driver.

Although it works as intended, without visible side effects, the stream of
events is rather large, and since the bypassing is completely new
behavior, I felt compelled to provide an option to turn it all off. 
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/input/mouse/bcm5974.c

@@ -96,6 +96,10 @@ static int debug = 1;
 module_param(debug, int, 0644);
 MODULE_PARM_DESC(debug, "Activate debugging output");
 
+static int nomt;
+module_param(nomt, int, 0644);
+MODULE_PARM_DESC(nomt, "Disable multitouch (MT) events");
+
 /* button data structure */
 struct bt_data {
 	u8 unknown1;		/* constant */
@@ -139,6 +143,7 @@ struct tp_finger {
 /* trackpad finger data size, empirically at least ten fingers */
 #define SIZEOF_FINGER		sizeof(struct tp_finger)
 #define SIZEOF_ALL_FINGERS	(16 * SIZEOF_FINGER)
+#define MAX_FINGER_ORIENTATION	16384
 
 /* device-specific parameters */
 struct bcm5974_param {
@@ -284,6 +289,28 @@ static void setup_events_to_report(struct input_dev *input_dev,
 	input_set_abs_params(input_dev, ABS_Y,
 				0, cfg->y.dim, cfg->y.fuzz, 0);
 
+	if (!nomt) {
+		/* finger touch area */
+		input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
+				     cfg->w.devmin, cfg->w.devmax, 0, 0);
+		input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR,
+				     cfg->w.devmin, cfg->w.devmax, 0, 0);
+		/* finger approach area */
+		input_set_abs_params(input_dev, ABS_MT_WIDTH_MAJOR,
+				     cfg->w.devmin, cfg->w.devmax, 0, 0);
+		input_set_abs_params(input_dev, ABS_MT_WIDTH_MINOR,
+				     cfg->w.devmin, cfg->w.devmax, 0, 0);
+		/* finger orientation */
+		input_set_abs_params(input_dev, ABS_MT_ORIENTATION,
+				     -MAX_FINGER_ORIENTATION,
+				     MAX_FINGER_ORIENTATION, 0, 0);
+		/* finger position */
+		input_set_abs_params(input_dev, ABS_MT_POSITION_X,
+				     cfg->x.devmin, cfg->x.devmax, 0, 0);
+		input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
+				     cfg->y.devmin, cfg->y.devmax, 0, 0);
+	}
+
 	__set_bit(EV_KEY, input_dev->evbit);
 	__set_bit(BTN_TOUCH, input_dev->keybit);
 	__set_bit(BTN_TOOL_FINGER, input_dev->keybit);
@@ -316,7 +343,7 @@ static int report_tp_state(struct bcm5974 *dev, int size)
 	const struct bcm5974_config *c = &dev->cfg;
 	const struct tp_finger *f;
 	struct input_dev *input = dev->input;
-	int raw_p, raw_w, raw_x, raw_y, raw_n;
+	int raw_p, raw_w, raw_x, raw_y, raw_n, i;
 	int ptest, origin, ibt = 0, nmin = 0, nmax = 0;
 	int abs_p = 0, abs_w = 0, abs_x = 0, abs_y = 0;
 
@@ -329,6 +356,30 @@ static int report_tp_state(struct bcm5974 *dev, int size)
 
 	/* always track the first finger; when detached, start over */
 	if (raw_n) {
+
+		/* report raw trackpad data */
+		if (!nomt) {
+			for (i = 0; i < raw_n; i++) {
+				int y = c->y.devmin + c->y.devmax;
+				input_report_abs(input, ABS_MT_TOUCH_MAJOR,
+						 raw2int(f[i].force_major));
+				input_report_abs(input, ABS_MT_TOUCH_MINOR,
+						 raw2int(f[i].force_minor));
+				input_report_abs(input, ABS_MT_WIDTH_MAJOR,
+						 raw2int(f[i].size_major));
+				input_report_abs(input, ABS_MT_WIDTH_MINOR,
+						 raw2int(f[i].size_minor));
+				input_report_abs(input, ABS_MT_ORIENTATION,
+						 MAX_FINGER_ORIENTATION -
+						 raw2int(f[i].orientation));
+				input_report_abs(input, ABS_MT_POSITION_X,
+						 raw2int(f[i].abs_x));
+				input_report_abs(input, ABS_MT_POSITION_Y,
+						 y - raw2int(f[i].abs_y));
+				input_mt_sync(input);
+			}
+		}
+
 		raw_p = raw2int(f->force_major);
 		raw_w = raw2int(f->size_major);
 		raw_x = raw2int(f->abs_x);