leds: trigger: Introduce audio mute LED trigger

This patch adds a new LED trigger for coupling the audio mixer change
with the LED on laptops or other devices.  Currently there are two
trigger types, "audio-mute" and "audio-micmute".

The audio driver triggers the LED brightness change via
ledtrig_audio_set() call with the proper type (either mute or
mic-mute).  OTOH, the consumers may call ledtrig_audio_get() for the
initial brightness value that may have been set by the audio driver
beforehand.

This new stuff will be used by HD-audio codec driver and some platform
drivers (thinkpad_acpi and dell-laptop, also upcoming huawei-wmi).

Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/leds.h b/include/linux/leds.h
index 7393a316d9fa..580cbaef789a 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -487,4 +487,24 @@ struct led_pattern {
 	int brightness;
 };
 
+enum led_audio {
+	LED_AUDIO_MUTE,		/* master mute LED */
+	LED_AUDIO_MICMUTE,	/* mic mute LED */
+	NUM_AUDIO_LEDS
+};
+
+#if IS_ENABLED(CONFIG_LEDS_TRIGGER_AUDIO)
+enum led_brightness ledtrig_audio_get(enum led_audio type);
+void ledtrig_audio_set(enum led_audio type, enum led_brightness state);
+#else
+static inline enum led_brightness ledtrig_audio_get(enum led_audio type)
+{
+	return LED_OFF;
+}
+static inline void ledtrig_audio_set(enum led_audio type,
+				     enum led_brightness state)
+{
+}
+#endif
+
 #endif		/* __LINUX_LEDS_H_INCLUDED */