hwdb: support pressing buttons on a keyboard

Support BTN_* codes with btn_ prefix and keys with KEY_ prefix
optionally removed.

hwdb/60-keyboard.hwdb

@@ -58,6 +58,8 @@
 #   KEYBOARD_KEY_<hex scan code>=<key code identifier>
 # The scan code should be expressed in hex lowercase. The key codes
 # are retrieved and normalized from the kernel input API header.
+# Keycodes are either KEY_* defines in lowercase with the key_ prefix
+# optionally removed or BTN_ defines in lowercase with btn_ preserved.
 #
 # An '!' as the first character of the key identifier string
 # will add the scan code to the AT keyboard's list of scan codes

hwdb/parse_hwdb.py

@@ -172,7 +172,9 @@ def check_one_keycode(prop, value):
     if value != '!' and ecodes is not None:
         key = 'KEY_' + value.upper()
         if key not in ecodes:
-            error('Keycode {} unknown', key)
+            key = value.upper()
+            if key not in ecodes:
+                error('Keycode {} unknown', key)
 
 def check_properties(groups):
     grammar = property_grammar()

src/udev/generate-keyboard-keys-gperf.sh

@@ -6,4 +6,5 @@ awk '   BEGIN {
         }
 
         /^KEY_/ { print tolower(substr($1 ,5)) ", " $1 }
+                { print tolower($1) ", " $1 }
 ' < "$1"

src/udev/generate-keyboard-keys-list.sh

@@ -1,4 +1,4 @@
 #!/bin/sh -eu
 
 $1 -dM -include linux/input.h - </dev/null | \
-        awk '/^#define[ \t]+KEY_[^ ]+[ \t]+[0-9K]/ { if ($2 != "KEY_MAX") { print $2 } }'
+        awk '/^#define[ \t]+(KEY|BTN)_[^ ]+[ \t]+[0-9BK]/ { if ($2 != "KEY_MAX") { print $2 } }'