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>

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);
 

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)

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 */

include/linux/input.h

@@ -53,6 +53,7 @@ struct input_absinfo {
 	__s32 maximum;
 	__s32 fuzz;
 	__s32 flat;
+	__s32 resolution;
 };
 
 #define EVIOCGVERSION		_IOR('E', 0x01, int)			/* get driver version */
@@ -1109,6 +1110,7 @@ struct input_dev {
 	int absmin[ABS_MAX + 1];
 	int absfuzz[ABS_MAX + 1];
 	int absflat[ABS_MAX + 1];
+	int absres[ABS_MAX + 1];
 
 	int (*open)(struct input_dev *dev);
 	void (*close)(struct input_dev *dev);