Some LED devices support two operation modes - torch and flash.
This patch provides support for flash LED devices in the LED subsystem
by introducing new sysfs attributes and kernel internal interface.
The attributes being introduced are: flash_brightness, flash_strobe,
flash_timeout, max_flash_timeout, max_flash_brightness, flash_fault,
indicator_brightness and  max_indicator_brightness. All the flash
related features are placed in a separate module.

The modifications aim to be compatible with V4L2 framework requirements
related to the flash devices management. The design assumes that V4L2
sub-device can take of the LED class device control and communicate
with it through the kernel internal interface. When V4L2 Flash sub-device
file is opened, the LED class device sysfs interface is made
unavailable.

Signed-off-by: Jacek Anaszewski <j.anaszew...@samsung.com>
Acked-by: Kyungmin Park <kyungmin.p...@samsung.com>
Cc: Bryan Wu <coolo...@gmail.com>
Cc: Richard Purdie <rpur...@rpsys.net>
---
 drivers/leds/Kconfig            |   11 +
 drivers/leds/Makefile           |    1 +
 drivers/leds/led-class-flash.c  |  557 +++++++++++++++++++++++++++++++++++++++
 drivers/leds/led-class.c        |    4 +
 include/linux/led-class-flash.h |  238 +++++++++++++++++
 include/linux/leds.h            |    3 +
 6 files changed, 814 insertions(+)
 create mode 100644 drivers/leds/led-class-flash.c
 create mode 100644 include/linux/led-class-flash.h

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 8c96e2d..3c58021 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -22,6 +22,17 @@ config LEDS_CLASS
          This option enables the led sysfs class in /sys/class/leds.  You'll
          need this to do anything useful with LEDs.  If unsure, say N.
 
+config LEDS_CLASS_FLASH
+       tristate "LED Flash Class Support"
+       depends on LEDS_CLASS
+       depends on OF
+       help
+         This option enables the flash led sysfs class in /sys/class/leds.
+         It wrapps LED Class and adds flash LEDs specific sysfs attributes
+         and kernel internal API to it. You'll need this to provide support
+         for the flash related features of a LED device. It can be built
+         as a module.
+
 comment "LED drivers"
 
 config LEDS_88PM860X
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index d8cc5f2..9238b8a 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -2,6 +2,7 @@
 # LED Core
 obj-$(CONFIG_NEW_LEDS)                 += led-core.o
 obj-$(CONFIG_LEDS_CLASS)               += led-class.o
+obj-$(CONFIG_LEDS_CLASS_FLASH)         += led-class-flash.o
 obj-$(CONFIG_LEDS_TRIGGERS)            += led-triggers.o
 
 # LED Platform Drivers
diff --git a/drivers/leds/led-class-flash.c b/drivers/leds/led-class-flash.c
new file mode 100644
index 0000000..f1ba539
--- /dev/null
+++ b/drivers/leds/led-class-flash.c
@@ -0,0 +1,557 @@
+/*
+ * LED Flash Class interface
+ *
+ * Copyright (C) 2014 Samsung Electronics Co., Ltd.
+ * Author: Jacek Anaszewski <j.anaszew...@samsung.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/device.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/led-class-flash.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include "leds.h"
+
+#define has_flash_op(flash, op)                                \
+       (flash && flash->ops->op)
+
+#define call_flash_op(flash, op, args...)              \
+       ((has_flash_op(flash, op)) ?                    \
+                       (flash->ops->op(flash, args)) : \
+                       -EINVAL)
+
+static ssize_t flash_brightness_store(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t size)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+       unsigned long state;
+       ssize_t ret;
+
+       mutex_lock(&led_cdev->led_access);
+
+       if (led_sysfs_is_disabled(led_cdev)) {
+               ret = -EBUSY;
+               goto unlock;
+       }
+
+       ret = kstrtoul(buf, 10, &state);
+       if (ret)
+               goto unlock;
+
+       ret = led_set_flash_brightness(flash, state);
+       if (ret < 0)
+               goto unlock;
+
+       ret = size;
+unlock:
+       mutex_unlock(&led_cdev->led_access);
+       return ret;
+}
+
+static ssize_t flash_brightness_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+
+       /* no lock needed for this */
+       led_update_flash_brightness(flash);
+
+       return sprintf(buf, "%u\n", flash->brightness.val);
+}
+static DEVICE_ATTR_RW(flash_brightness);
+
+static ssize_t max_flash_brightness_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+
+       return sprintf(buf, "%u\n", flash->brightness.max);
+}
+static DEVICE_ATTR_RO(max_flash_brightness);
+
+static ssize_t indicator_brightness_store(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t size)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+       unsigned long state;
+       ssize_t ret;
+
+       mutex_lock(&led_cdev->led_access);
+
+       if (led_sysfs_is_disabled(led_cdev)) {
+               ret = -EBUSY;
+               goto unlock;
+       }
+
+       ret = kstrtoul(buf, 10, &state);
+       if (ret)
+               goto unlock;
+
+       ret = led_set_indicator_brightness(flash, state);
+       if (ret < 0)
+               goto unlock;
+
+       ret = size;
+unlock:
+       mutex_unlock(&led_cdev->led_access);
+       return ret;
+}
+
+static ssize_t indicator_brightness_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+
+       /* no lock needed for this */
+       led_update_indicator_brightness(flash);
+
+       return sprintf(buf, "%u\n", flash->indicator_brightness->val);
+}
+static DEVICE_ATTR_RW(indicator_brightness);
+
+static ssize_t max_indicator_brightness_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+
+       return sprintf(buf, "%u\n", flash->indicator_brightness->max);
+}
+static DEVICE_ATTR_RO(max_indicator_brightness);
+
+static ssize_t flash_strobe_store(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t size)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+       unsigned long state;
+       ssize_t ret = -EINVAL;
+
+       mutex_lock(&led_cdev->led_access);
+
+       if (led_sysfs_is_disabled(led_cdev)) {
+               ret = -EBUSY;
+               goto unlock;
+       }
+
+       ret = kstrtoul(buf, 10, &state);
+       if (ret)
+               goto unlock;
+
+       if (state < 0 || state > 1) {
+               ret = -EINVAL;
+               goto unlock;
+       }
+
+       ret = led_set_flash_strobe(flash, state);
+       if (ret < 0)
+               goto unlock;
+       ret = size;
+unlock:
+       mutex_unlock(&led_cdev->led_access);
+       return ret;
+}
+
+static ssize_t flash_strobe_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+       bool state;
+       int ret;
+
+       /* no lock needed for this */
+       ret = led_get_flash_strobe(flash, &state);
+       if (ret < 0)
+               return ret;
+
+       return sprintf(buf, "%u\n", state);
+}
+static DEVICE_ATTR_RW(flash_strobe);
+
+static ssize_t flash_timeout_store(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t size)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+       unsigned long flash_timeout;
+       ssize_t ret;
+
+       mutex_lock(&led_cdev->led_access);
+
+       if (led_sysfs_is_disabled(led_cdev)) {
+               ret = -EBUSY;
+               goto unlock;
+       }
+
+       ret = kstrtoul(buf, 10, &flash_timeout);
+       if (ret)
+               goto unlock;
+
+       ret = led_set_flash_timeout(flash, flash_timeout);
+       if (ret < 0)
+               goto unlock;
+
+       ret = size;
+unlock:
+       mutex_unlock(&led_cdev->led_access);
+       return ret;
+}
+
+static ssize_t flash_timeout_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+
+       return sprintf(buf, "%u\n", flash->timeout.val);
+}
+static DEVICE_ATTR_RW(flash_timeout);
+
+static ssize_t max_flash_timeout_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+
+       return sprintf(buf, "%u\n", flash->timeout.max);
+}
+static DEVICE_ATTR_RO(max_flash_timeout);
+
+static ssize_t flash_fault_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct led_classdev *led_cdev = dev_get_drvdata(dev);
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+       u32 fault;
+       int ret;
+
+       ret = led_get_flash_fault(flash, &fault);
+       if (ret < 0)
+               return -EINVAL;
+
+       return sprintf(buf, "0x%8.8x\n", fault);
+}
+static DEVICE_ATTR_RO(flash_fault);
+
+static struct attribute *led_flash_strobe_attrs[] = {
+       &dev_attr_flash_strobe.attr,
+       NULL,
+};
+
+static struct attribute *led_flash_indicator_attrs[] = {
+       &dev_attr_indicator_brightness.attr,
+       &dev_attr_max_indicator_brightness.attr,
+       NULL,
+};
+
+static struct attribute *led_flash_timeout_attrs[] = {
+       &dev_attr_flash_timeout.attr,
+       &dev_attr_max_flash_timeout.attr,
+       NULL,
+};
+
+static struct attribute *led_flash_brightness_attrs[] = {
+       &dev_attr_flash_brightness.attr,
+       &dev_attr_max_flash_brightness.attr,
+       NULL,
+};
+
+static struct attribute *led_flash_fault_attrs[] = {
+       &dev_attr_flash_fault.attr,
+       NULL,
+};
+
+static struct attribute_group led_flash_strobe_group = {
+       .attrs = led_flash_strobe_attrs,
+};
+
+static struct attribute_group led_flash_brightness_group = {
+       .attrs = led_flash_brightness_attrs,
+};
+
+static struct attribute_group led_flash_timeout_group = {
+       .attrs = led_flash_timeout_attrs,
+};
+
+static struct attribute_group led_flash_indicator_group = {
+       .attrs = led_flash_indicator_attrs,
+};
+
+static struct attribute_group led_flash_fault_group = {
+       .attrs = led_flash_fault_attrs,
+};
+
+static void led_flash_resume(struct led_classdev *led_cdev)
+{
+       struct led_classdev_flash *flash = lcdev_to_flash(led_cdev);
+
+       call_flash_op(flash, flash_brightness_set, flash->brightness.val);
+       call_flash_op(flash, timeout_set, flash->timeout.val);
+       call_flash_op(flash, indicator_brightness_set,
+                               flash->indicator_brightness->val);
+}
+
+static void led_flash_remove_sysfs_groups(struct led_classdev_flash *flash)
+{
+       struct led_classdev *led_cdev = &flash->led_cdev;
+       int i;
+
+       for (i = 0; i < LED_FLASH_MAX_SYSFS_GROUPS; ++i)
+               if (flash->sysfs_groups[i])
+                       sysfs_remove_group(&led_cdev->dev->kobj,
+                                               flash->sysfs_groups[i]);
+}
+
+static int led_flash_create_sysfs_groups(struct led_classdev_flash *flash)
+{
+       struct led_classdev *led_cdev = &flash->led_cdev;
+       const struct led_flash_ops *ops = flash->ops;
+       int ret, num_sysfs_groups = 0;
+
+       memset(flash->sysfs_groups, 0, sizeof(*flash->sysfs_groups) *
+                                               LED_FLASH_MAX_SYSFS_GROUPS);
+
+       ret = sysfs_create_group(&led_cdev->dev->kobj, &led_flash_strobe_group);
+       if (ret < 0)
+               goto err_create_group;
+       flash->sysfs_groups[num_sysfs_groups++] = &led_flash_strobe_group;
+
+       if (flash->indicator_brightness) {
+               ret = sysfs_create_group(&led_cdev->dev->kobj,
+                                       &led_flash_indicator_group);
+               if (ret < 0)
+                       goto err_create_group;
+               flash->sysfs_groups[num_sysfs_groups++] =
+                                       &led_flash_indicator_group;
+       }
+
+       if (ops->flash_brightness_set) {
+               ret = sysfs_create_group(&led_cdev->dev->kobj,
+                                       &led_flash_brightness_group);
+               if (ret < 0)
+                       goto err_create_group;
+               flash->sysfs_groups[num_sysfs_groups++] =
+                                       &led_flash_brightness_group;
+       }
+
+       if (ops->timeout_set) {
+               ret = sysfs_create_group(&led_cdev->dev->kobj,
+                                       &led_flash_timeout_group);
+               if (ret < 0)
+                       goto err_create_group;
+               flash->sysfs_groups[num_sysfs_groups++] =
+                                       &led_flash_timeout_group;
+       }
+
+       if (ops->fault_get) {
+               ret = sysfs_create_group(&led_cdev->dev->kobj,
+                                       &led_flash_fault_group);
+               if (ret < 0)
+                       goto err_create_group;
+               flash->sysfs_groups[num_sysfs_groups++] =
+                                       &led_flash_fault_group;
+       }
+
+       return 0;
+
+err_create_group:
+       led_flash_remove_sysfs_groups(flash);
+       return ret;
+}
+
+int led_classdev_flash_register(struct device *parent,
+                               struct led_classdev_flash *flash,
+                               struct device_node *node)
+{
+       struct led_classdev *led_cdev;
+       const struct led_flash_ops *ops;
+       int ret = -EINVAL;
+
+       if (!flash)
+               return -EINVAL;
+
+       led_cdev = &flash->led_cdev;
+
+       /* Torch capability is default for every LED Flash Class device */
+       led_cdev->flags |= LED_DEV_CAP_TORCH;
+
+       if (led_cdev->flags & LED_DEV_CAP_FLASH) {
+               if (!led_cdev->torch_brightness_set)
+                       return -EINVAL;
+
+               ops = flash->ops;
+               if (!ops || !ops->strobe_set)
+                       return -EINVAL;
+
+               if ((led_cdev->flags & LED_DEV_CAP_INDICATOR) &&
+                   (!flash->indicator_brightness ||
+                    !ops->indicator_brightness_set))
+                       return -EINVAL;
+
+               led_cdev->flash_resume = led_flash_resume;
+       }
+
+       /* Register led class device */
+       ret = led_classdev_register(parent, led_cdev);
+       if (ret < 0)
+               return -EINVAL;
+
+       /* Create flash led specific sysfs attributes */
+       ret = led_flash_create_sysfs_groups(flash);
+       if (ret < 0)
+               goto err_create_sysfs_groups;
+
+       return 0;
+
+err_create_sysfs_groups:
+       led_classdev_unregister(led_cdev);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(led_classdev_flash_register);
+
+void led_classdev_flash_unregister(struct led_classdev_flash *flash)
+{
+       if (!flash)
+               return;
+
+       led_flash_remove_sysfs_groups(flash);
+       led_classdev_unregister(&flash->led_cdev);
+}
+EXPORT_SYMBOL_GPL(led_classdev_flash_unregister);
+
+int led_set_flash_strobe(struct led_classdev_flash *flash, bool state)
+{
+       return call_flash_op(flash, strobe_set, state);
+}
+EXPORT_SYMBOL_GPL(led_set_flash_strobe);
+
+int led_get_flash_strobe(struct led_classdev_flash *flash, bool *state)
+{
+       return call_flash_op(flash, strobe_get, state);
+}
+EXPORT_SYMBOL_GPL(led_get_flash_strobe);
+
+static void led_clamp_align(struct led_flash_setting *s)
+{
+       u32 v, offset;
+
+       v = s->val + s->step / 2;
+       v = clamp(v, s->min, s->max);
+       offset = v - s->min;
+       offset = s->step * (offset / s->step);
+       s->val = s->min + offset;
+}
+
+int led_set_flash_timeout(struct led_classdev_flash *flash, u32 timeout)
+{
+       struct led_classdev *led_cdev = &flash->led_cdev;
+       struct led_flash_setting *s = &flash->timeout;
+       int ret = 0;
+
+       s->val = timeout;
+       led_clamp_align(s);
+
+       if (!(led_cdev->flags & LED_SUSPENDED))
+               ret = call_flash_op(flash, timeout_set, s->val);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(led_set_flash_timeout);
+
+int led_get_flash_fault(struct led_classdev_flash *flash, u32 *fault)
+{
+       return call_flash_op(flash, fault_get, fault);
+}
+EXPORT_SYMBOL_GPL(led_get_flash_fault);
+
+int led_set_flash_brightness(struct led_classdev_flash *flash,
+                               u32 brightness)
+{
+       struct led_classdev *led_cdev = &flash->led_cdev;
+       struct led_flash_setting *s = &flash->brightness;
+       int ret = 0;
+
+       s->val = brightness;
+       led_clamp_align(s);
+
+       if (!(led_cdev->flags & LED_SUSPENDED))
+               ret = call_flash_op(flash, flash_brightness_set, s->val);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(led_set_flash_brightness);
+
+int led_update_flash_brightness(struct led_classdev_flash *flash)
+{
+       struct led_flash_setting *s = &flash->brightness;
+       u32 brightness;
+       int ret = 0;
+
+       if (has_flash_op(flash, flash_brightness_get)) {
+               ret = call_flash_op(flash, flash_brightness_get,
+                                               &brightness);
+               if (ret < 0)
+                       return ret;
+               s->val = brightness;
+       }
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(led_update_flash_brightness);
+
+int led_set_indicator_brightness(struct led_classdev_flash *flash,
+                                       u32 brightness)
+{
+       struct led_classdev *led_cdev = &flash->led_cdev;
+       struct led_flash_setting *s = flash->indicator_brightness;
+       int ret = 0;
+
+       if (!s)
+               return -EINVAL;
+
+       s->val = brightness;
+       led_clamp_align(s);
+
+       if (!(led_cdev->flags & LED_SUSPENDED))
+               ret = call_flash_op(flash, indicator_brightness_set, s->val);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(led_set_indicator_brightness);
+
+int led_update_indicator_brightness(struct led_classdev_flash *flash)
+{
+       struct led_flash_setting *s = flash->indicator_brightness;
+       u32 brightness;
+       int ret = 0;
+
+       if (!s)
+               return -EINVAL;
+
+       if (has_flash_op(flash, indicator_brightness_get)) {
+               ret = call_flash_op(flash, indicator_brightness_get,
+                                                       &brightness);
+               if (ret < 0)
+                       return ret;
+               s->val = brightness;
+       }
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(led_update_indicator_brightness);
+
+MODULE_AUTHOR("Jacek Anaszewski <j.anaszew...@samsung.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LED Flash Class Interface");
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 5a11a07..d398b87 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -183,6 +183,10 @@ EXPORT_SYMBOL_GPL(led_classdev_suspend);
 void led_classdev_resume(struct led_classdev *led_cdev)
 {
        led_cdev->brightness_set(led_cdev, led_cdev->brightness);
+
+       if (led_cdev->flash_resume)
+               led_cdev->flash_resume(led_cdev);
+
        led_cdev->flags &= ~LED_SUSPENDED;
 }
 EXPORT_SYMBOL_GPL(led_classdev_resume);
diff --git a/include/linux/led-class-flash.h b/include/linux/led-class-flash.h
new file mode 100644
index 0000000..fcc15ed
--- /dev/null
+++ b/include/linux/led-class-flash.h
@@ -0,0 +1,238 @@
+/*
+ * LED Flash Class interface
+ *
+ * Copyright (C) 2014 Samsung Electronics Co., Ltd.
+ * Author: Jacek Anaszewski <j.anaszew...@samsung.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.
+ *
+ */
+#ifndef __LINUX_FLASH_LEDS_H_INCLUDED
+#define __LINUX_FLASH_LEDS_H_INCLUDED
+
+#include <linux/leds.h>
+
+struct led_classdev_flash;
+struct device_node;
+
+/*
+ * Supported led fault bits - must be kept in synch
+ * with V4L2_FLASH_FAULT bits.
+ */
+#define LED_FAULT_OVER_VOLTAGE          V4L2_FLASH_FAULT_OVER_VOLTAGE
+#define LED_FAULT_TIMEOUT               V4L2_FLASH_FAULT_TIMEOUT
+#define LED_FAULT_OVER_TEMPERATURE      V4L2_FLASH_FAULT_OVER_TEMPERATURE
+#define LED_FAULT_SHORT_CIRCUIT                 V4L2_FLASH_FAULT_SHORT_CIRCUIT
+#define LED_FAULT_OVER_CURRENT          V4L2_FLASH_FAULT_OVER_CURRENT
+#define LED_FAULT_INDICATOR             V4L2_FLASH_FAULT_INDICATOR
+#define LED_FAULT_UNDER_VOLTAGE                 V4L2_FLASH_FAULT_UNDER_VOLTAGE
+#define LED_FAULT_INPUT_VOLTAGE                 V4L2_FLASH_FAULT_INPUT_VOLTAGE
+#define LED_FAULT_LED_OVER_TEMPERATURE  V4L2_FLASH_OVER_TEMPERATURE
+
+#define LED_FLASH_MAX_SYSFS_GROUPS 5
+
+struct led_flash_ops {
+       /* set flash brightness */
+       int (*flash_brightness_set)(struct led_classdev_flash *flash,
+                                       u32 brightness);
+       /* get flash brightness */
+       int (*flash_brightness_get)(struct led_classdev_flash *flash,
+                                       u32 *brightness);
+       /* set flash indicator brightness */
+       int (*indicator_brightness_set)(struct led_classdev_flash *flash,
+                                       u32 brightness);
+       /* get flash indicator brightness */
+       int (*indicator_brightness_get)(struct led_classdev_flash *flash,
+                                       u32 *brightness);
+       /* set flash strobe state */
+       int (*strobe_set)(struct led_classdev_flash *flash, bool state);
+       /* get flash strobe state */
+       int (*strobe_get)(struct led_classdev_flash *flash, bool *state);
+       /* set flash timeout */
+       int (*timeout_set)(struct led_classdev_flash *flash, u32 timeout);
+       /* get the flash LED fault */
+       int (*fault_get)(struct led_classdev_flash *flash, u32 *fault);
+};
+
+/*
+ * Current value of a flash setting along
+ * with its constraints.
+ */
+struct led_flash_setting {
+       /* maximum allowed value */
+       u32 min;
+       /* maximum allowed value */
+       u32 max;
+       /* step value */
+       u32 step;
+       /* current value */
+       u32 val;
+};
+
+/*
+ * Aggregated flash settings - designed for ease
+ * of passing initialization data to the clients
+ * wrapping a LED Flash class device.
+ */
+struct led_flash_config {
+       struct led_flash_setting torch_brightness;
+       struct led_flash_setting flash_brightness;
+       struct led_flash_setting indicator_brightness;
+       struct led_flash_setting flash_timeout;
+       u32 flash_faults;
+};
+
+struct led_classdev_flash {
+       /* led-flash-manager uses it to link flashes */
+       struct list_head list;
+       /* led class device */
+       struct led_classdev led_cdev;
+       /* flash led specific ops */
+       const struct led_flash_ops *ops;
+
+       /* flash sysfs groups */
+       struct attribute_group *sysfs_groups[LED_FLASH_MAX_SYSFS_GROUPS];
+
+       /* flash brightness value in microamperes along with its constraints */
+       struct led_flash_setting brightness;
+
+       /* timeout value in microseconds along with its constraints */
+       struct led_flash_setting timeout;
+
+       /*
+        * Indicator brightness value in microamperes along with
+        * its constraints - this is an optional setting and must
+        * be allocated by the driver if the device supports privacy
+        * indicator led.
+        */
+       struct led_flash_setting *indicator_brightness;
+};
+
+static inline struct led_classdev_flash *lcdev_to_flash(
+                                               struct led_classdev *lcdev)
+{
+       return container_of(lcdev, struct led_classdev_flash, led_cdev);
+}
+
+/**
+ * led_classdev_flash_register - register a new object of led_classdev class
+                                with support for flash LEDs
+ * @parent: the flash LED to register
+ * @flash: the led_classdev_flash structure for this device
+ * @node: device tree node of the LED Flash Class device - it must be
+         initialized if the device is to be registered in the flash manager
+ *
+ * Returns: 0 on success or negative error value on failure
+ */
+int led_classdev_flash_register(struct device *parent,
+                               struct led_classdev_flash *flash,
+                               struct device_node *node);
+
+/**
+ * led_classdev_flash_unregister - unregisters an object of led_classdev class
+                                  with support for flash LEDs
+ * @flash: the flash LED to unregister
+ *
+ * Unregisters a previously registered via led_classdev_flash_register object
+ */
+void led_classdev_flash_unregister(struct led_classdev_flash *flash);
+
+/**
+ * led_set_flash_strobe - setup flash strobe
+ * @flash: the flash LED to set strobe on
+ * @state: 1 - strobe flash, 0 - stop flash strobe
+ *
+ * Setup flash strobe - trigger flash strobe
+ *
+ * Returns: 0 on success or negative error value on failure
+ */
+extern int led_set_flash_strobe(struct led_classdev_flash *flash,
+                               bool state);
+
+/**
+ * led_get_flash_strobe - get flash strobe status
+ * @flash: the flash LED to query
+ * @state: 1 - flash is strobing, 0 - flash is off
+ *
+ * Check whether the flash is strobing at the moment or not.
+ *
+u* Returns: 0 on success or negative error value on failure
+ */
+extern int led_get_flash_strobe(struct led_classdev_flash *flash,
+                               bool *state);
+/**
+ * led_set_flash_brightness - set flash LED brightness
+ * @flash: the flash LED to set
+ * @brightness: the brightness to set it to
+ *
+ * Returns: 0 on success or negative error value on failure
+ *
+ * Set a flash LED's brightness.
+ */
+extern int led_set_flash_brightness(struct led_classdev_flash *flash,
+                                       u32 brightness);
+
+/**
+ * led_update_flash_brightness - update flash LED brightness
+ * @flash: the flash LED to query
+ *
+ * Get a flash LED's current brightness and update led_flash->brightness
+ * member with the obtained value.
+ *
+ * Returns: 0 on success or negative error value on failure
+ */
+extern int led_update_flash_brightness(struct led_classdev_flash *flash);
+
+/**
+ * led_set_flash_timeout - set flash LED timeout
+ * @flash: the flash LED to set
+ * @timeout: the flash timeout to set it to
+ *
+ * Set the flash strobe duration. The duration set by the driver
+ * is returned in the timeout argument and may differ from the
+ * one that was originally passed.
+ *
+ * Returns: 0 on success or negative error value on failure
+ */
+extern int led_set_flash_timeout(struct led_classdev_flash *flash,
+                                       u32 timeout);
+
+/**
+ * led_get_flash_fault - get the flash LED fault
+ * @flash: the flash LED to query
+ * @fault: bitmask containing flash faults
+ *
+ * Get the flash LED fault.
+ *
+ * Returns: 0 on success or negative error value on failure
+ */
+extern int led_get_flash_fault(struct led_classdev_flash *flash,
+                                       u32 *fault);
+
+/**
+ * led_set_indicator_brightness - set indicator LED brightness
+ * @flash: the flash LED to set
+ * @brightness: the brightness to set it to
+ *
+ * Set an indicator LED's brightness.
+ *
+ * Returns: 0 on success or negative error value on failure
+ */
+extern int led_set_indicator_brightness(struct led_classdev_flash *flash,
+                                       u32 led_brightness);
+
+/**
+ * led_update_indicator_brightness - update flash indicator LED brightness
+ * @flash: the flash LED to query
+ *
+ * Get a flash indicator LED's current brightness and update
+ * led_flash->indicator_brightness member with the obtained value.
+ *
+ * Returns: 0 on success or negative error value on failure
+ */
+extern int led_update_indicator_brightness(struct led_classdev_flash *flash);
+
+
+#endif /* __LINUX_FLASH_LEDS_H_INCLUDED */
diff --git a/include/linux/leds.h b/include/linux/leds.h
index bc2a570..70fa0ad 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -45,6 +45,8 @@ struct led_classdev {
 #define LED_BLINK_INVERT       (1 << 19)
 #define LED_SYSFS_DISABLE      (1 << 20)
 #define LED_DEV_CAP_TORCH      (1 << 21)
+#define LED_DEV_CAP_FLASH      (1 << 22)
+#define LED_DEV_CAP_INDICATOR  (1 << 23)
 
        /* Set LED brightness level */
        /* Must not sleep, use a workqueue if needed */
@@ -83,6 +85,7 @@ struct led_classdev {
        unsigned long            blink_delay_on, blink_delay_off;
        struct timer_list        blink_timer;
        int                      blink_brightness;
+       void                    (*flash_resume)(struct led_classdev *led_cdev);
 
        struct work_struct      set_brightness_work;
        int                     delayed_set_value;
-- 
1.7.9.5

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