input: document gamepad API and add extra keycodes

Until today all gamepad input drivers report their data differently. It is
nearly impossible to write applications for more than one device in a
generic way. Therefore, this patch introduces a uniform gamepad API which
will be used for all new drivers.

Instead of mapping buttons by their labels, we now map them by position.
This allows applications to work with any gamepad regardless of the labels
on the buttons. Furthermore, we standardize the ABS_* codes for analog
triggers and sticks.

For D-Pads the long overdue BTN_DPAD_* codes are introduced. They should
be fairly obvious how to use. To avoid confusion, the action buttons now
have BTN_EAST/SOUTH/WEST/NORTH aliases.

Reported-by: Todd Showalter <todd@electronjump.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/uapi/linux/input.h b/include/uapi/linux/input.h
index 4649ee35b605..8f82ad29fc30 100644
--- a/include/uapi/linux/input.h
+++ b/include/uapi/linux/input.h
@@ -507,10 +507,14 @@ struct input_keymap_entry {
 
 #define BTN_GAMEPAD             0x130
 #define BTN_A                   0x130
+#define BTN_SOUTH               0x130
 #define BTN_B                   0x131
+#define BTN_EAST                0x131
 #define BTN_C                   0x132
 #define BTN_X                   0x133
+#define BTN_NORTH               0x133
 #define BTN_Y                   0x134
+#define BTN_WEST                0x134
 #define BTN_Z                   0x135
 #define BTN_TL                  0x136
 #define BTN_TR                  0x137
@@ -707,6 +711,11 @@ struct input_keymap_entry {
 #define KEY_ATTENDANT_TOGGLE    0x21d   /* Attendant call on or off */
 #define KEY_LIGHTS_TOGGLE       0x21e   /* Reading light on or off */
 
+#define BTN_DPAD_UP             0x220
+#define BTN_DPAD_DOWN           0x221
+#define BTN_DPAD_LEFT           0x222
+#define BTN_DPAD_RIGHT          0x223
+
 #define BTN_TRIGGER_HAPPY               0x2c0
 #define BTN_TRIGGER_HAPPY1              0x2c0
 #define BTN_TRIGGER_HAPPY2              0x2c1