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>

3 files changed, 66 insertions, 0 deletions

diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index eaa286dc494e..49794b47b51c 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -100,4 +100,12 @@ config LEDS_TRIGGER_TRANSIENT
           GPIO/PWM based hardware.
           If unsure, say Y.
 
+config LEDS_TRIGGER_CAMERA
+        tristate "LED Camera Flash/Torch Trigger"
+        depends on LEDS_TRIGGERS
+        help
+          This allows LEDs to be controlled as a camera flash/torch device.
+          This enables direct flash/torch on/off by the driver, kernel space.
+          If unsure, say Y.
+
 endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 554e46ee4c24..1abf48dacf7e 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_LEDS_TRIGGER_GPIO)		+= ledtrig-gpio.o
 obj-$(CONFIG_LEDS_TRIGGER_CPU)          += ledtrig-cpu.o
 obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)   += ledtrig-default-on.o
 obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT)    += ledtrig-transient.o
+obj-$(CONFIG_LEDS_TRIGGER_CAMERA)       += ledtrig-camera.o
diff --git a/drivers/leds/trigger/ledtrig-camera.c b/drivers/leds/trigger/ledtrig-camera.c
new file mode 100644
index 000000000000..9bd73a8bad5c
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-camera.c
@@ -0,0 +1,57 @@
+/*
+ * Camera Flash and Torch On/Off Trigger
+ *
+ * based on ledtrig-ide-disk.c
+ *
+ * Copyright 2013 Texas Instruments
+ *
+ * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+
+DEFINE_LED_TRIGGER(ledtrig_flash);
+DEFINE_LED_TRIGGER(ledtrig_torch);
+
+void ledtrig_flash_ctrl(bool on)
+{
+        enum led_brightness brt = on ? LED_FULL : LED_OFF;
+
+        led_trigger_event(ledtrig_flash, brt);
+}
+EXPORT_SYMBOL_GPL(ledtrig_flash_ctrl);
+
+void ledtrig_torch_ctrl(bool on)
+{
+        enum led_brightness brt = on ? LED_FULL : LED_OFF;
+
+        led_trigger_event(ledtrig_torch, brt);
+}
+EXPORT_SYMBOL_GPL(ledtrig_torch_ctrl);
+
+static int __init ledtrig_camera_init(void)
+{
+        led_trigger_register_simple("flash", &ledtrig_flash);
+        led_trigger_register_simple("torch", &ledtrig_torch);
+        return 0;
+}
+module_init(ledtrig_camera_init);
+
+static void __exit ledtrig_camera_exit(void)
+{
+        led_trigger_unregister_simple(ledtrig_torch);
+        led_trigger_unregister_simple(ledtrig_flash);
+}
+module_exit(ledtrig_camera_exit);
+
+MODULE_DESCRIPTION("LED Trigger for Camera Flash/Torch Control");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL");