hwdb: add a touchpad hwdb

Currently used to tag devices in the new Lenovo *50 series and the X1 Carbon
3rd. These laptops re-introduced the physical trackpoint buttons that were
missing from the *40 series but those buttons are now wired up to the
touchpad.

The touchpad now sends BTN_0, BTN_1 and BTN_2 for the trackpoint. The same
button codes were used in older touchpads that had dedicated scroll up/down
buttons. Input drivers need to work around this and thus know what they're
dealing with.

For the previous gen we introduced INPUT_PROP_TOPBUTTONPAD in the kernel, but
the resulting mess showed that these per-device quirks should really live in
userspace.

The list currently includes the X1 Carbon 3rd PNPID, others will be added as
get to know which PNPID they have.

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>

hwdb/70-touchpad.hwdb

@@ -0,0 +1,39 @@
+# This file is part of systemd.
+#
+# The lookup keys are composed in:
+#   70-touchpad.rules
+#
+# Note: The format of the "touchpad:" prefix match key is a
+# contract between the rules file and the hardware data, it might
+# change in later revisions to support more or better matches, it
+# is not necessarily expected to be a stable ABI.
+#
+# Match string format:
+# touchpad:pnpid:<pnpid>:
+#
+# To add local entries, create a new file
+#   /etc/udev/hwdb.d/71-touchpad-local.hwdb
+# and add your rules there. To load the new rules execute (as root):
+#   udevadm hwdb --update
+#   udevadm trigger /dev/input/eventXX
+# where /dev/input/eventXX is the touchpad in question. If in
+# doubt, simply use /dev/input/event* to reload all input rules.
+#
+# If your changes are generally applicable, open a bug report on
+#   http://bugs.freedesktop.org/enter_bug.cgi?product=systemd
+# and include your new rules, a description of the device, and the
+# output of
+#   udevadm info /dev/input/eventXX
+# (or /dev/input/event*).
+#
+# Allowed properties are:
+#    TOUCHPAD_HAS_TRACKPOINT_BUTTONS=1
+#
+# If the TOUCHPAD_HAS_TRACKPOINT_BUTTONS property is set, this
+# device has # the trackpoint buttons wired up to the touchpad as
+# BTN_0, BTN_1 and BTN_2. This affects the Lenovo X1 Carbon 3rd
+# and the *50 series (T450, T550, etc.)
+
+# Lenovo X1 Carbon 3rd
+touchpad:pnpid:*LEN0048*:
+ TOUCHPAD_HAS_TRACKPOINT_BUTTONS=1

hwdb/Makefile.am

@@ -10,7 +10,8 @@ dist_udevhwdb_DATA = \
 	20-sdio-vendor-model.hwdb \
 	20-usb-classes.hwdb \
 	20-usb-vendor-model.hwdb \
-	70-mouse.hwdb
+	70-mouse.hwdb \
+	70-touchpad.hwdb
 
 if ENABLE_KEYMAP
 dist_udevhwdb_DATA += \

rules/70-touchpad.rules

@@ -0,0 +1,12 @@
+# do not edit this file, it will be overwritten on update
+
+ACTION=="remove", GOTO="touchpad_end"
+KERNEL!="event*", GOTO="touchpad_end"
+ENV{ID_INPUT_TOUCHPAD}=="", GOTO="touchpad_end"
+
+# touchpad:pnpid:<pnpid>:*
+KERNELS=="serio1", \
+    IMPORT{builtin}="hwdb 'touchpad:pnpid:$attr{firmware_id}:'", \
+    GOTO="touchpad_end"
+
+LABEL="touchpad_end"

rules/Makefile.am

@@ -13,6 +13,7 @@ dist_udevrules_DATA = \
 	61-accelerometer.rules \
 	64-btrfs.rules \
 	70-mouse.rules \
+	70-touchpad.rules \
 	75-net-description.rules \
 	75-probe_mtd.rules \
 	75-tty-description.rules \