Input: synaptics - add support for reporting x/y resolution

Synaptics uses anisotropic coordinate system.  On some wide touchpads
vertical resolution can be twice as high as horizontal which causes
unequal sensitivity on x/y directions.  Add support for reading the
resolution with EVIOCGABS ioctl.

Signed-off-by: Tero Saarni <tero.saarni@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

3 files changed, 39 insertions, 3 deletions

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index c238116400b..114efd8dc8f 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -626,8 +626,11 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                                 abs.maximum = dev->absmax[t];
                                 abs.fuzz = dev->absfuzz[t];
                                 abs.flat = dev->absflat[t];
+                                abs.resolution = dev->absres[t];
 
-                                if (copy_to_user(p, &abs, sizeof(struct input_absinfo)))
+                                if (copy_to_user(p, &abs, min_t(size_t,
+                                                                _IOC_SIZE(cmd),
+                                                                sizeof(struct input_absinfo))))
                                         return -EFAULT;
 
                                 return 0;
@@ -654,8 +657,9 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 
                                 t = _IOC_NR(cmd) & ABS_MAX;
 
-                                if (copy_from_user(&abs, p,
-                                                sizeof(struct input_absinfo)))
+                                if (copy_from_user(&abs, p, min_t(size_t,
+                                                                  _IOC_SIZE(cmd),
+                                                                  sizeof(struct input_absinfo))))
                                         return -EFAULT;
 
                                 /*
@@ -670,6 +674,8 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                                 dev->absmax[t] = abs.maximum;
                                 dev->absfuzz[t] = abs.fuzz;
                                 dev->absflat[t] = abs.flat;
+                                dev->absres[t] = _IOC_SIZE(cmd) < sizeof(struct input_absinfo) ?
+                                                        0 : abs.resolution;
 
                                 spin_unlock_irq(&dev->event_lock);
 
diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index f3e4f7b0240..19984bf06ca 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -180,6 +180,29 @@ static int synaptics_identify(struct psmouse *psmouse)
         return -1;
 }
 
+/*
+ * Read touchpad resolution
+ * Resolution is left zero if touchpad does not support the query
+ */
+static int synaptics_resolution(struct psmouse *psmouse)
+{
+        struct synaptics_data *priv = psmouse->private;
+        unsigned char res[3];
+
+        if (SYN_ID_MAJOR(priv->identity) < 4)
+                return 0;
+
+        if (synaptics_send_cmd(psmouse, SYN_QUE_RESOLUTION, res))
+                return 0;
+
+        if ((res[0] != 0) && (res[1] & 0x80) && (res[2] != 0)) {
+                priv->x_res = res[0]; /* x resolution in units/mm */
+                priv->y_res = res[2]; /* y resolution in units/mm */
+        }
+
+        return 0;
+}
+
 static int synaptics_query_hardware(struct psmouse *psmouse)
 {
         if (synaptics_identify(psmouse))
@@ -188,6 +211,8 @@ static int synaptics_query_hardware(struct psmouse *psmouse)
                 return -1;
         if (synaptics_capability(psmouse))
                 return -1;
+        if (synaptics_resolution(psmouse))
+                return -1;
 
         return 0;
 }
@@ -563,6 +588,9 @@ static void set_input_params(struct input_dev *dev, struct synaptics_data *priv)
         clear_bit(EV_REL, dev->evbit);
         clear_bit(REL_X, dev->relbit);
         clear_bit(REL_Y, dev->relbit);
+
+        dev->absres[ABS_X] = priv->x_res;
+        dev->absres[ABS_Y] = priv->y_res;
 }
 
 static void synaptics_disconnect(struct psmouse *psmouse)
diff --git a/drivers/input/mouse/synaptics.h b/drivers/input/mouse/synaptics.h
index 02aa4cf7bc7..30238215175 100644
--- a/drivers/input/mouse/synaptics.h
+++ b/drivers/input/mouse/synaptics.h
@@ -97,6 +97,8 @@ struct synaptics_data {
         unsigned long int capabilities;         /* Capabilities */
         unsigned long int ext_cap;              /* Extended Capabilities */
         unsigned long int identity;             /* Identification */
+        int x_res;                              /* X resolution in units/mm */
+        int y_res;                              /* Y resolution in units/mm */
 
         unsigned char pkt_type;                 /* packet type - old, new, etc */
         unsigned char mode;                     /* current mode byte */