Input: elantech - report multitouch with proper ABS_MT messages

Multitouch info was reported only via a old protocol used by the
proprietary X driver from elantech. Let's report the multitouch info
also following the official MT protocol. It's semi-mt because the device
only reports the lowest/highest coordinates.

This was done following the multi-touch-protocol.txt documentation, and
inspired by the bcm5974 and elantech implementations. Testing was light
as there is not many applications using this protocol yet, but the X
synaptics driver didn't complain and the X multitouch driver behaved
correctly.

Signed-off-by: Éric Piel <eric.piel@tremplin-utc.net>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 34 insertions, 5 deletions

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index 5cde11f4ef5e..32648b34b115 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/input.h>
+#include <linux/input/mt.h>
 #include <linux/serio.h>
 #include <linux/libps2.h>
 #include "psmouse.h"
@@ -242,6 +243,27 @@ static void elantech_report_absolute_v1(struct psmouse *psmouse)
         input_sync(dev);
 }
 
+static void elantech_set_slot(struct input_dev *dev, int slot, bool active,
+                              unsigned int x, unsigned 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, y);
+        }
+}
+
+/* x1 < x2 and y1 < y2 when two fingers, x = y = 0 when not pressed */
+static void elantech_report_semi_mt_data(struct input_dev *dev,
+                                         unsigned int num_fingers,
+                                         unsigned int x1, unsigned int y1,
+                                         unsigned int x2, unsigned int y2)
+{
+        elantech_set_slot(dev, 0, num_fingers != 0, x1, y1);
+        elantech_set_slot(dev, 1, num_fingers == 2, x2, y2);
+}
+
 /*
  * Interpret complete data packets and report absolute mode input events for
  * hardware version 2. (6 byte packets)
@@ -251,7 +273,7 @@ static void elantech_report_absolute_v2(struct psmouse *psmouse)
         struct elantech_data *etd = psmouse->private;
         struct input_dev *dev = psmouse->dev;
         unsigned char *packet = psmouse->packet;
-        int fingers, x1, y1, x2, y2, width = 0, pres = 0;
+        unsigned int fingers, x1 = 0, y1 = 0, x2 = 0, y2 = 0, width = 0, pres = 0;
 
         /* byte 0: n1  n0   .   .   .   .   R   L */
         fingers = (packet[0] & 0xc0) >> 6;
@@ -271,14 +293,16 @@ static void elantech_report_absolute_v2(struct psmouse *psmouse)
                  * byte 1:  .   .   .   .   .  x10 x9  x8
                  * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
                  */
-                input_report_abs(dev, ABS_X,
-                        ((packet[1] & 0x07) << 8) | packet[2]);
+                x1 = ((packet[1] & 0x07) << 8) | packet[2];
                 /*
                  * byte 4:  .   .   .   .   .   .  y9  y8
                  * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
                  */
-                input_report_abs(dev, ABS_Y,
-                        ETP_YMAX_V2 - (((packet[4] & 0x03) << 8) | packet[5]));
+                y1 = ETP_YMAX_V2 - (((packet[4] & 0x03) << 8) | packet[5]);
+
+                input_report_abs(dev, ABS_X, x1);
+                input_report_abs(dev, ABS_Y, y1);
+
                 pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
                 width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
                 break;
@@ -321,6 +345,7 @@ static void elantech_report_absolute_v2(struct psmouse *psmouse)
                 break;
         }
 
+        elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
         input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
         input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
         input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
@@ -495,6 +520,10 @@ static void elantech_set_input_params(struct psmouse *psmouse)
                         input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
                                              ETP_WMAX_V2, 0, 0);
                 }
+                __set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
+                input_mt_init_slots(dev, 2);
+                input_set_abs_params(dev, ABS_MT_POSITION_X, ETP_XMIN_V2, ETP_XMAX_V2, 0, 0);
+                input_set_abs_params(dev, ABS_MT_POSITION_Y, ETP_YMIN_V2, ETP_YMAX_V2, 0, 0);
                 input_set_abs_params(dev, ABS_HAT0X, ETP_2FT_XMIN, ETP_2FT_XMAX, 0, 0);
                 input_set_abs_params(dev, ABS_HAT0Y, ETP_2FT_YMIN, ETP_2FT_YMAX, 0, 0);
                 input_set_abs_params(dev, ABS_HAT1X, ETP_2FT_XMIN, ETP_2FT_XMAX, 0, 0);