Add a property to toggle function key mode

On some keyboards, the multimedia function keys are overlaid with the F
keys. This property enables clients to switch the primary mode of these F
keys between function keys and multimedia keys.
Some keyboards provide an Fn key to toggle between the modes. This is
hardware-specific and may or may not work on any given keyboard device.

The current imlementation is only hooked up to apple keyboards.
The kernel provides a tweak to enable/disable.

/sys/module/hid_apple/parameters/fnmode
    0 .. keyboard sends Fx keys, Fn disabled
    1 .. keyboard sends multimedia keys, Fn toggles to function keys
    2 .. keyboard sends function keys, Fn toggles to multimedia keys

If fnmode is on 0, we force it to 2.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Michel Dänzer <michel@daenzer.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/evdev.h b/src/evdev.h
index 1741e59..ff50d0a 100644
--- a/src/evdev.h
+++ b/src/evdev.h
@@ -85,6 +85,13 @@
 /* Number of longs needed to hold the given number of bits */
 #define NLONGS(x) (((x) + LONG_BITS - 1) / LONG_BITS)
 
+/* Function key mode */
+enum fkeymode {
+    FKEYMODE_UNKNOWN = 0,
+    FKEYMODE_FKEYS,       /* function keys send function keys */
+    FKEYMODE_MMKEYS,      /* function keys send multimedia keys */
+};
+
 /* axis specific data for wheel emulation */
 typedef struct {
     int up_button;
@@ -197,6 +204,8 @@ typedef struct {
     /* Event queue used to defer keyboard/button events until EV_SYN time. */
     int                     num_queue;
     EventQueueRec           queue[EVDEV_MAXQUEUE];
+
+    enum fkeymode           fkeymode;
 } EvdevRec, *EvdevPtr;
 
 /* Event posting functions */
@@ -243,4 +252,5 @@ void EvdevMBEmuInitProperty(DeviceIntPtr);
 void Evdev3BEmuInitProperty(DeviceIntPtr);
 void EvdevWheelEmuInitProperty(DeviceIntPtr);
 void EvdevDragLockInitProperty(DeviceIntPtr);
+void EvdevAppleInitProperty(DeviceIntPtr);
 #endif