leds: add camera LED triggers

Some LED devices support flash/torch functionality through the LED subsystem.
This patch enables direct LED trigger controls by the driver.
Flash on/off and torch on/off can be done simply by other driver space.
Two trigger APIs are added, ledtrig_flash_ctrl() and ledtrig_torch_ctrl().

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 2d8c0b4..0287ab2 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -218,6 +218,14 @@
 static inline void ledtrig_ide_activity(void) {}
 #endif
 
+#if defined(CONFIG_LEDS_TRIGGER_CAMERA) || defined(CONFIG_LEDS_TRIGGER_CAMERA_MODULE)
+extern void ledtrig_flash_ctrl(bool on);
+extern void ledtrig_torch_ctrl(bool on);
+#else
+static inline void ledtrig_flash_ctrl(bool on) {}
+static inline void ledtrig_torch_ctrl(bool on) {}
+#endif
+
 /*
  * Generic LED platform data for describing LED names and default triggers.
  */