LM355x family devices provide flash, torch and indicator functions.
 This patch support LED trigger feature.
 Using LED trigger APIs(), other driver simply turn on/off the flash, torch
 and indicator.

 Platform data
  the name of LED trigger is configurable.

 Documentation
  example and detailed description added.

Signed-off-by: Milo(Woogyom) Kim <milo....@ti.com>
---
 Documentation/leds/leds-lm3556.txt        |   62 +++++++++++++++++++++++++++++
 drivers/leds/leds-lm355x.c                |    3 ++
 include/linux/platform_data/leds-lm355x.h |    8 ++++
 3 files changed, 73 insertions(+)

diff --git a/Documentation/leds/leds-lm3556.txt 
b/Documentation/leds/leds-lm3556.txt
index d9eb91b..73244cd 100644
--- a/Documentation/leds/leds-lm3556.txt
+++ b/Documentation/leds/leds-lm3556.txt
@@ -83,3 +83,65 @@ and register it in the platform init function
 Example:
        board_register_i2c_bus(4, 400,
                                board_i2c_ch4, ARRAY_SIZE(board_i2c_ch4));
+
+Support LED Triggers
+--------------------
+Flash, torch and indicator can be controlled not only by an user-space but also
+by other drivers, kernel space.
+For example, flash turns on by camera driver internally.
+To support this functionality, LED trigger is registered.
+The name of LED trigger is configurable in the platform data.
+
+Example: LED trigger name for flash
+#include <linux/platform_data/leds-lm355x.h>
+
+struct lm355x_trigger_name lm3556_trigger_name = {
+       .flash = "flash",
+};
+
+struct lm355x_platform_data lm3556_pdata = {
+       ...
+       .trigger = &lm3556_trigger_name,
+};
+
+Example: Flash control in simple camera driver
+#include <linux/leds.h>
+
+#ifdef CONFIG_LEDS_TRIGGERS
+DEFINE_LED_TRIGGER(flash_led_trigger);
+#endif
+
+static int foo_camera_init()
+{
+       ...
+
+#ifdef CONFIG_LEDS_TRIGGERS
+       /* should be same name as in lm355x_platform_data */
+       led_trigger_register_simple("flash", &flash_led_trigger);
+#endif
+
+       ...
+}
+
+static void foo_camera_exit()
+{
+       ...
+
+#ifdef CONFIG_LEDS_TRIGGERS
+       led_trigger_unregister_simple(flash_led_trigger);
+#endif
+
+       ...
+}
+
+#ifdef CONFIG_LEDS_TRIGGERS
+static void foo_camera_flash_ctrl(bool on)
+{
+       if (on)
+               led_trigger_event(flash_led_trigger, LED_FULL);
+       else
+               led_trigger_event(flash_led_trigger, LED_OFF);
+}
+#else
+#define foo_camera_flash_ctrl  NULL
+#endif
diff --git a/drivers/leds/leds-lm355x.c b/drivers/leds/leds-lm355x.c
index 65d7928..29df4c0 100644
--- a/drivers/leds/leds-lm355x.c
+++ b/drivers/leds/leds-lm355x.c
@@ -477,6 +477,7 @@ static int lm355x_probe(struct i2c_client *client,
        chip->cdev_flash.name = "flash";
        chip->cdev_flash.max_brightness = 16;
        chip->cdev_flash.brightness_set = lm355x_strobe_brightness_set;
+       chip->cdev_flash.default_trigger = pdata->trigger->flash;
        err = led_classdev_register((struct device *)
                                    &client->dev, &chip->cdev_flash);
        if (err < 0)
@@ -486,6 +487,7 @@ static int lm355x_probe(struct i2c_client *client,
        chip->cdev_torch.name = "torch";
        chip->cdev_torch.max_brightness = 8;
        chip->cdev_torch.brightness_set = lm355x_torch_brightness_set;
+       chip->cdev_torch.default_trigger = pdata->trigger->torch;
        err = led_classdev_register((struct device *)
                                    &client->dev, &chip->cdev_torch);
        if (err < 0)
@@ -499,6 +501,7 @@ static int lm355x_probe(struct i2c_client *client,
        else
                chip->cdev_indicator.max_brightness = 8;
        chip->cdev_indicator.brightness_set = lm355x_indicator_brightness_set;
+       chip->cdev_indicator.default_trigger = pdata->trigger->indicator;
        err = led_classdev_register((struct device *)
                                    &client->dev, &chip->cdev_indicator);
        if (err < 0)
diff --git a/include/linux/platform_data/leds-lm355x.h 
b/include/linux/platform_data/leds-lm355x.h
index b88724b..b64d312 100644
--- a/include/linux/platform_data/leds-lm355x.h
+++ b/include/linux/platform_data/leds-lm355x.h
@@ -42,6 +42,12 @@ enum lm355x_pmode {
        LM355x_PMODE_ENABLE = 0x04,
 };
 
+struct lm355x_trigger_name {
+       const char *flash;
+       const char *torch;
+       const char *indicator;
+};
+
 /*
  * struct lm3554_platform_data
  * @pin_strobe: strobe input
@@ -55,6 +61,7 @@ enum lm355x_pmode {
  *              lm3554-ledi/ntc
  *              lm3556-temp pin
  * @pass_mode : pass mode
+ * @triger    : led triggers for flash, torch and indicator
  */
 struct lm355x_platform_data {
        enum lm355x_strobe pin_strobe;
@@ -63,4 +70,5 @@ struct lm355x_platform_data {
        enum lm355x_ntc ntc_pin;
 
        enum lm355x_pmode pass_mode;
+       struct lm355x_trigger_name *trigger;
 };
-- 
1.7.9.5

Best Regards,
Milo


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