Input: alps - Rushmore and v7 resolution support

Add support for querying the physical size from the touchpad for Rushmore
and v7 touchpads, and use that to tell userspace the device resolution.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

2 files changed, 50 insertions, 0 deletions

diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
index 76d372f0084c..a59a1a64b674 100644
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -1792,6 +1792,45 @@ error:
         return -1;
 }
 
+static int alps_get_v3_v7_resolution(struct psmouse *psmouse, int reg_pitch)
+{
+        int reg, x_pitch, y_pitch, x_electrode, y_electrode, x_phys, y_phys;
+        struct alps_data *priv = psmouse->private;
+
+        reg = alps_command_mode_read_reg(psmouse, reg_pitch);
+        if (reg < 0)
+                return reg;
+
+        x_pitch = (char)(reg << 4) >> 4; /* sign extend lower 4 bits */
+        x_pitch = 50 + 2 * x_pitch; /* In 0.1 mm units */
+
+        y_pitch = (char)reg >> 4; /* sign extend upper 4 bits */
+        y_pitch = 36 + 2 * y_pitch; /* In 0.1 mm units */
+
+        reg = alps_command_mode_read_reg(psmouse, reg_pitch + 1);
+        if (reg < 0)
+                return reg;
+
+        x_electrode = (char)(reg << 4) >> 4; /* sign extend lower 4 bits */
+        x_electrode = 17 + x_electrode;
+
+        y_electrode = (char)reg >> 4; /* sign extend upper 4 bits */
+        y_electrode = 13 + y_electrode;
+
+        x_phys = x_pitch * (x_electrode - 1); /* In 0.1 mm units */
+        y_phys = y_pitch * (y_electrode - 1); /* In 0.1 mm units */
+
+        priv->x_res = priv->x_max * 10 / x_phys; /* units / mm */
+        priv->y_res = priv->y_max * 10 / y_phys; /* units / mm */
+
+        psmouse_dbg(psmouse,
+                    "pitch %dx%d num-electrodes %dx%d physical size %dx%d mm res %dx%d\n",
+                    x_pitch, y_pitch, x_electrode, y_electrode,
+                    x_phys / 10, y_phys / 10, priv->x_res, priv->y_res);
+
+        return 0;
+}
+
 static int alps_hw_init_rushmore_v3(struct psmouse *psmouse)
 {
         struct alps_data *priv = psmouse->private;
@@ -1812,6 +1851,9 @@ static int alps_hw_init_rushmore_v3(struct psmouse *psmouse)
             alps_command_mode_write_reg(psmouse, 0xc2cb, 0x00))
                 goto error;
 
+        if (alps_get_v3_v7_resolution(psmouse, 0xc2da))
+                goto error;
+
         reg_val = alps_command_mode_read_reg(psmouse, 0xc2c6);
         if (reg_val == -1)
                 goto error;
@@ -1997,6 +2039,9 @@ static int alps_hw_init_v7(struct psmouse *psmouse)
             alps_command_mode_read_reg(psmouse, 0xc2d9) == -1)
                 goto error;
 
+        if (alps_get_v3_v7_resolution(psmouse, 0xc397))
+                goto error;
+
         if (alps_command_mode_write_reg(psmouse, 0xc2c9, 0x64))
                 goto error;
 
@@ -2230,6 +2275,9 @@ static void alps_set_abs_params_mt(struct alps_data *priv,
         input_set_abs_params(dev1, ABS_MT_POSITION_X, 0, priv->x_max, 0, 0);
         input_set_abs_params(dev1, ABS_MT_POSITION_Y, 0, priv->y_max, 0, 0);
 
+        input_abs_set_res(dev1, ABS_MT_POSITION_X, priv->x_res);
+        input_abs_set_res(dev1, ABS_MT_POSITION_Y, priv->y_res);
+
         input_mt_init_slots(dev1, MAX_TOUCHES, INPUT_MT_POINTER |
                 INPUT_MT_DROP_UNUSED | INPUT_MT_TRACK | INPUT_MT_SEMI_MT);
 
diff --git a/drivers/input/mouse/alps.h b/drivers/input/mouse/alps.h
index a98ac9ba5043..66240b47819a 100644
--- a/drivers/input/mouse/alps.h
+++ b/drivers/input/mouse/alps.h
@@ -174,6 +174,8 @@ struct alps_data {
         int y_max;
         int x_bits;
         int y_bits;
+        unsigned int x_res;
+        unsigned int y_res;
 
         int (*hw_init)(struct psmouse *psmouse);
         void (*process_packet)(struct psmouse *psmouse);