Input: add INPUT_PROP_POINTING_STICK property

It is useful for userspace to know that there not dealing with a regular
mouse but rather with a pointing stick (e.g. a trackpoint) so that
userspace can e.g. automatically enable middle button scrollwheel
emulation.

It is impossible to tell the difference from the evdev info without
resorting to putting a list of device / driver names in userspace, this is
undesirable.

Add a property which allows userspace to see if a device is a pointing
stick, and set it on all the pointing stick drivers.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/alps.c

@@ -2373,6 +2373,9 @@ int alps_init(struct psmouse *psmouse)
 	dev2->keybit[BIT_WORD(BTN_LEFT)] =
 		BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT);
 
+	if (priv->flags & ALPS_DUALPOINT)
+		__set_bit(INPUT_PROP_POINTING_STICK, dev2->propbit);
+
 	if (input_register_device(priv->dev2))
 		goto init_fail;
 

drivers/input/mouse/elantech.c

@@ -1614,6 +1614,9 @@ int elantech_init(struct psmouse *psmouse)
 		tp_dev->keybit[BIT_WORD(BTN_LEFT)] =
 			BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) |
 			BIT_MASK(BTN_RIGHT);
+
+		__set_bit(INPUT_PROP_POINTING_STICK, tp_dev->propbit);
+
 		error = input_register_device(etd->tp_dev);
 		if (error < 0)
 			goto init_fail_tp_reg;

drivers/input/mouse/synaptics_usb.c

@@ -387,6 +387,7 @@ static int synusb_probe(struct usb_interface *intf,
 		__set_bit(EV_REL, input_dev->evbit);
 		__set_bit(REL_X, input_dev->relbit);
 		__set_bit(REL_Y, input_dev->relbit);
+		__set_bit(INPUT_PROP_POINTING_STICK, input_dev->propbit);
 		input_set_abs_params(input_dev, ABS_PRESSURE, 0, 127, 0, 0);
 	} else {
 		input_set_abs_params(input_dev, ABS_X,

drivers/input/mouse/trackpoint.c

@@ -393,6 +393,8 @@ int trackpoint_detect(struct psmouse *psmouse, bool set_properties)
 	if ((button_info & 0x0f) >= 3)
 		__set_bit(BTN_MIDDLE, psmouse->dev->keybit);
 
+	__set_bit(INPUT_PROP_POINTING_STICK, psmouse->dev->propbit);
+
 	trackpoint_defaults(psmouse->private);
 
 	error = trackpoint_power_on_reset(&psmouse->ps2dev);

include/uapi/linux/input.h

@@ -165,6 +165,7 @@ struct input_keymap_entry {
 #define INPUT_PROP_BUTTONPAD		0x02	/* has button(s) under pad */
 #define INPUT_PROP_SEMI_MT		0x03	/* touch rectangle only */
 #define INPUT_PROP_TOPBUTTONPAD		0x04	/* softbuttons at top of pad */
+#define INPUT_PROP_POINTING_STICK	0x05	/* is a pointing stick */
 
 #define INPUT_PROP_MAX			0x1f
 #define INPUT_PROP_CNT			(INPUT_PROP_MAX + 1)