Input: synaptics - refactor agm packet parsing

When a Synaptics touchpad is in "AGM" mode, and multiple fingers are
detected, the touchpad sends alternating "Advanced Gesture Mode" (AGM) and
"Simple Gesture Mode" (SGM) packets.
  The AGM packets have w=2, and contain reduced resolution finger data.
  The SGM packets have w={0,1} and contain full resolution finger data.

Refactor the parsing of agm packets to its own function, and rename the
synaptics_data.mt field to .agm to indicate that it contains the contents of
the last agm packet.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Acked-by: Chase Douglas <chase.douglas@canonical.com>
Acked-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

2 files changed, 19 insertions, 6 deletions

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index b0008bcb26fc..34bcc1fc59fd 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -419,6 +419,17 @@ static void synaptics_pt_create(struct psmouse *psmouse)
  *      Functions to interpret the absolute mode packets
  ****************************************************************************/
 
+static void synaptics_parse_agm(const unsigned char buf[],
+                                struct synaptics_data *priv)
+{
+        struct synaptics_hw_state *agm = &priv->agm;
+
+        /* Gesture packet: (x, y, z) at half resolution */
+        agm->x = (((buf[4] & 0x0f) << 8) | buf[1]) << 1;
+        agm->y = (((buf[4] & 0xf0) << 4) | buf[2]) << 1;
+        agm->z = ((buf[3] & 0x30) | (buf[5] & 0x0f)) << 1;
+}
+
 static int synaptics_parse_hw_state(const unsigned char buf[],
                                     struct synaptics_data *priv,
                                     struct synaptics_hw_state *hw)
@@ -453,10 +464,7 @@ static int synaptics_parse_hw_state(const unsigned char buf[],
                 }
 
                 if (SYN_CAP_ADV_GESTURE(priv->ext_cap_0c) && hw->w == 2) {
-                        /* Gesture packet: (x, y, z) at half resolution */
-                        priv->mt.x = (((buf[4] & 0x0f) << 8) | buf[1]) << 1;
-                        priv->mt.y = (((buf[4] & 0xf0) << 4) | buf[2]) << 1;
-                        priv->mt.z = ((buf[3] & 0x30) | (buf[5] & 0x0f)) << 1;
+                        synaptics_parse_agm(buf, priv);
                         return 1;
                 }
 
@@ -595,7 +603,8 @@ static void synaptics_process_packet(struct psmouse *psmouse)
         }
 
         if (SYN_CAP_ADV_GESTURE(priv->ext_cap_0c))
-                synaptics_report_semi_mt_data(dev, &hw, &priv->mt, num_fingers);
+                synaptics_report_semi_mt_data(dev, &hw, &priv->agm,
+                                              num_fingers);
 
         /* Post events
          * BTN_TOUCH has to be first as mousedev relies on it when doing
diff --git a/drivers/input/mouse/synaptics.h b/drivers/input/mouse/synaptics.h
index ca040aa80fa7..a9efbf3e3ea1 100644
--- a/drivers/input/mouse/synaptics.h
+++ b/drivers/input/mouse/synaptics.h
@@ -146,7 +146,11 @@ struct synaptics_data {
 
         struct serio *pt_port;                  /* Pass-through serio port */
 
-        struct synaptics_hw_state mt;           /* current gesture packet */
+        /*
+         * Last received Advanced Gesture Mode (AGM) packet. An AGM packet
+         * contains position data for a second contact, at half resolution.
+         */
+        struct synaptics_hw_state agm;
 };
 
 void synaptics_module_init(void);