[PATCH libinput] evdev: retrieve udev tags

[Benjamin Tissoires]

Udev already tags the devices by opening each of them and analyzing their
features. We are basically re-doing this in libinput.

The advantage of udev tags over the plain heuristic from libinput is that
users (or driver writers) can force some tags that are not detected by
common rules. For instance, the pad part of the Wacom tablets is difficult
to discriminate from a joystlick or a pointer.

This patch adds a udev_tags field in struct evdev_device and populates
it accroding to the current known udev built in tags.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires at gmail.com>
---

Hi,

I had to rely on the udev tags when working on the tablet branch.
I think master could benefit from it as well, given one of the recent patches
Hans sent.

Cheers,
Benjamin


 src/evdev.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/evdev.h | 11 +++++++++++
 2 files changed, 62 insertions(+)

diff --git a/src/evdev.c b/src/evdev.c
index 24d30e0..838a5e5 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -49,6 +49,24 @@ enum evdev_key_type {
 	EVDEV_KEY_TYPE_BUTTON,
 };
 
+struct evdev_udev_tag_match {
+	const char *name;
+	enum evdev_device_udev_tags tag;
+};
+
+static const struct evdev_udev_tag_match evdev_udev_tag_matches[] = {
+	{"ID_INPUT_KEYBOARD",		EVDEV_UDEV_TAG_KEYBOARD},
+	{"ID_INPUT_MOUSE",		EVDEV_UDEV_TAG_MOUSE},
+	{"ID_INPUT_TOUCHPAD",		EVDEV_UDEV_TAG_TOUCHPAD},
+	{"ID_INPUT_TOUCHSCREEN",	EVDEV_UDEV_TAG_TOUCHSCREEN},
+	{"ID_INPUT_TABLET",		EVDEV_UDEV_TAG_TABLET},
+	{"ID_INPUT_JOYSTICK",		EVDEV_UDEV_TAG_JOYSTICK},
+	{"ID_INPUT_ACCELEROMETER",	EVDEV_UDEV_TAG_ACCELEROMETER},
+
+	/* sentinel value */
+	{ 0 },
+};
+
 static void
 hw_set_key_down(struct evdev_device *device, int code, int pressed)
 {
@@ -1340,6 +1358,18 @@ evdev_configure_device(struct evdev_device *device)
 	has_keyboard = 0;
 	has_touch = 0;
 
+	if (device->udev_tags)
+		log_info(libinput,
+			 "input device '%s', %s is tagged by udev as:%s%s%s%s%s%s\n",
+			 device->devname, devnode,
+			 device->udev_tags & EVDEV_UDEV_TAG_KEYBOARD ? " Keyboard" : "",
+			 device->udev_tags & EVDEV_UDEV_TAG_MOUSE ? " Mouse" : "",
+			 device->udev_tags & EVDEV_UDEV_TAG_TOUCHPAD ? " Touchpad" : "",
+			 device->udev_tags & EVDEV_UDEV_TAG_TOUCHSCREEN ? " Touchscreen" : "",
+			 device->udev_tags & EVDEV_UDEV_TAG_TABLET ? " Tablet" : "",
+			 device->udev_tags & EVDEV_UDEV_TAG_JOYSTICK ? " Joystick" : "",
+			 device->udev_tags & EVDEV_UDEV_TAG_ACCELEROMETER ? " Accelerometer" : "");
+
 	for (i = BTN_JOYSTICK; i <= BTN_PINKIE; i++)
 		if (libevdev_has_event_code(evdev, EV_KEY, i))
 			has_joystick_button = 1;
@@ -1559,6 +1589,25 @@ out:
 	return rc;
 }
 
+static enum evdev_device_udev_tags
+evdev_device_get_udev_tags(struct evdev_device *device,
+			   struct udev_device *udev_device)
+{
+	const char *prop;
+	enum evdev_device_udev_tags tags = 0;
+	const struct evdev_udev_tag_match *match = evdev_udev_tag_matches;
+
+	while (match->name) {
+		prop = udev_device_get_property_value(device->udev_device,
+						      match->name);
+		if (prop)
+			tags |= match->tag;
+
+		match++;
+	}
+	return tags;
+}
+
 struct evdev_device *
 evdev_device_create(struct libinput_seat *seat,
 		    struct udev_device *udev_device)
@@ -1620,6 +1669,8 @@ evdev_device_create(struct libinput_seat *seat,
 	matrix_init_identity(&device->abs.usermatrix);
 	matrix_init_identity(&device->abs.default_calibration);
 
+	device->udev_tags = evdev_device_get_udev_tags(device, udev_device);
+
 	if (evdev_configure_device(device) == -1)
 		goto err;
 
diff --git a/src/evdev.h b/src/evdev.h
index fc70a28..91c8624 100644
--- a/src/evdev.h
+++ b/src/evdev.h
@@ -57,6 +57,16 @@ enum evdev_device_tags {
 	EVDEV_TAG_TOUCHPAD_TRACKPOINT = (1 << 3),
 };
 
+enum evdev_device_udev_tags {
+	EVDEV_UDEV_TAG_KEYBOARD = (1 << 0),
+	EVDEV_UDEV_TAG_MOUSE = (1 << 1),
+	EVDEV_UDEV_TAG_TOUCHPAD = (1 << 2),
+	EVDEV_UDEV_TAG_TOUCHSCREEN = (1 << 3),
+	EVDEV_UDEV_TAG_TABLET = (1 << 4),
+	EVDEV_UDEV_TAG_JOYSTICK = (1 << 5),
+	EVDEV_UDEV_TAG_ACCELEROMETER = (1 << 6),
+};
+
 struct mt_slot {
 	int32_t seat_slot;
 	int32_t x, y;
@@ -128,6 +138,7 @@ struct evdev_device {
 	enum evdev_event_type pending_event;
 	enum evdev_device_seat_capability seat_caps;
 	enum evdev_device_tags tags;
+	enum evdev_device_udev_tags udev_tags;
 
 	int is_mt;
 	int suspended;
-- 
2.1.0