v4.19.13 snapshot.
diff --git a/drivers/leds/led-class-flash.c b/drivers/leds/led-class-flash.c
new file mode 100644
index 0000000..cf39827
--- /dev/null
+++ b/drivers/leds/led-class-flash.c
@@ -0,0 +1,400 @@
+/*
+ * LED Flash class interface
+ *
+ * Copyright (C) 2015 Samsung Electronics Co., Ltd.
+ * Author: Jacek Anaszewski <j.anaszewski@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/led-class-flash.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include "leds.h"
+
+#define has_flash_op(fled_cdev, op)				\
+	(fled_cdev && fled_cdev->ops->op)
+
+#define call_flash_op(fled_cdev, op, args...)		\
+	((has_flash_op(fled_cdev, op)) ?			\
+			(fled_cdev->ops->op(fled_cdev, args)) :	\
+			-EINVAL)
+
+static const char * const led_flash_fault_names[] = {
+	"led-over-voltage",
+	"flash-timeout-exceeded",
+	"controller-over-temperature",
+	"controller-short-circuit",
+	"led-power-supply-over-current",
+	"indicator-led-fault",
+	"led-under-voltage",
+	"controller-under-voltage",
+	"led-over-temperature",
+};
+
+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 *fled_cdev = lcdev_to_flcdev(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(fled_cdev, 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 *fled_cdev = lcdev_to_flcdev(led_cdev);
+
+	/* no lock needed for this */
+	led_update_flash_brightness(fled_cdev);
+
+	return sprintf(buf, "%u\n", fled_cdev->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 *fled_cdev = lcdev_to_flcdev(led_cdev);
+
+	return sprintf(buf, "%u\n", fled_cdev->brightness.max);
+}
+static DEVICE_ATTR_RO(max_flash_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 *fled_cdev = lcdev_to_flcdev(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 > 1) {
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	ret = led_set_flash_strobe(fled_cdev, 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 *fled_cdev = lcdev_to_flcdev(led_cdev);
+	bool state;
+	int ret;
+
+	/* no lock needed for this */
+	ret = led_get_flash_strobe(fled_cdev, &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 *fled_cdev = lcdev_to_flcdev(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(fled_cdev, 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 *fled_cdev = lcdev_to_flcdev(led_cdev);
+
+	return sprintf(buf, "%u\n", fled_cdev->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 *fled_cdev = lcdev_to_flcdev(led_cdev);
+
+	return sprintf(buf, "%u\n", fled_cdev->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 *fled_cdev = lcdev_to_flcdev(led_cdev);
+	u32 fault, mask = 0x1;
+	char *pbuf = buf;
+	int i, ret, buf_len;
+
+	ret = led_get_flash_fault(fled_cdev, &fault);
+	if (ret < 0)
+		return -EINVAL;
+
+	*buf = '\0';
+
+	for (i = 0; i < LED_NUM_FLASH_FAULTS; ++i) {
+		if (fault & mask) {
+			buf_len = sprintf(pbuf, "%s ",
+					  led_flash_fault_names[i]);
+			pbuf += buf_len;
+		}
+		mask <<= 1;
+	}
+
+	return sprintf(buf, "%s\n", buf);
+}
+static DEVICE_ATTR_RO(flash_fault);
+
+static struct attribute *led_flash_strobe_attrs[] = {
+	&dev_attr_flash_strobe.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 const struct attribute_group led_flash_strobe_group = {
+	.attrs = led_flash_strobe_attrs,
+};
+
+static const struct attribute_group led_flash_timeout_group = {
+	.attrs = led_flash_timeout_attrs,
+};
+
+static const struct attribute_group led_flash_brightness_group = {
+	.attrs = led_flash_brightness_attrs,
+};
+
+static const 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 *fled_cdev = lcdev_to_flcdev(led_cdev);
+
+	call_flash_op(fled_cdev, flash_brightness_set,
+					fled_cdev->brightness.val);
+	call_flash_op(fled_cdev, timeout_set, fled_cdev->timeout.val);
+}
+
+static void led_flash_init_sysfs_groups(struct led_classdev_flash *fled_cdev)
+{
+	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
+	const struct led_flash_ops *ops = fled_cdev->ops;
+	const struct attribute_group **flash_groups = fled_cdev->sysfs_groups;
+
+	int num_sysfs_groups = 0;
+
+	flash_groups[num_sysfs_groups++] = &led_flash_strobe_group;
+
+	if (ops->flash_brightness_set)
+		flash_groups[num_sysfs_groups++] = &led_flash_brightness_group;
+
+	if (ops->timeout_set)
+		flash_groups[num_sysfs_groups++] = &led_flash_timeout_group;
+
+	if (ops->fault_get)
+		flash_groups[num_sysfs_groups++] = &led_flash_fault_group;
+
+	led_cdev->groups = flash_groups;
+}
+
+int led_classdev_flash_register(struct device *parent,
+				struct led_classdev_flash *fled_cdev)
+{
+	struct led_classdev *led_cdev;
+	const struct led_flash_ops *ops;
+	int ret;
+
+	if (!fled_cdev)
+		return -EINVAL;
+
+	led_cdev = &fled_cdev->led_cdev;
+
+	if (led_cdev->flags & LED_DEV_CAP_FLASH) {
+		if (!led_cdev->brightness_set_blocking)
+			return -EINVAL;
+
+		ops = fled_cdev->ops;
+		if (!ops || !ops->strobe_set)
+			return -EINVAL;
+
+		led_cdev->flash_resume = led_flash_resume;
+
+		/* Select the sysfs attributes to be created for the device */
+		led_flash_init_sysfs_groups(fled_cdev);
+	}
+
+	/* Register led class device */
+	ret = led_classdev_register(parent, led_cdev);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(led_classdev_flash_register);
+
+void led_classdev_flash_unregister(struct led_classdev_flash *fled_cdev)
+{
+	if (!fled_cdev)
+		return;
+
+	led_classdev_unregister(&fled_cdev->led_cdev);
+}
+EXPORT_SYMBOL_GPL(led_classdev_flash_unregister);
+
+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 *fled_cdev, u32 timeout)
+{
+	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
+	struct led_flash_setting *s = &fled_cdev->timeout;
+
+	s->val = timeout;
+	led_clamp_align(s);
+
+	if (!(led_cdev->flags & LED_SUSPENDED))
+		return call_flash_op(fled_cdev, timeout_set, s->val);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(led_set_flash_timeout);
+
+int led_get_flash_fault(struct led_classdev_flash *fled_cdev, u32 *fault)
+{
+	return call_flash_op(fled_cdev, fault_get, fault);
+}
+EXPORT_SYMBOL_GPL(led_get_flash_fault);
+
+int led_set_flash_brightness(struct led_classdev_flash *fled_cdev,
+				u32 brightness)
+{
+	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
+	struct led_flash_setting *s = &fled_cdev->brightness;
+
+	s->val = brightness;
+	led_clamp_align(s);
+
+	if (!(led_cdev->flags & LED_SUSPENDED))
+		return call_flash_op(fled_cdev, flash_brightness_set, s->val);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(led_set_flash_brightness);
+
+int led_update_flash_brightness(struct led_classdev_flash *fled_cdev)
+{
+	struct led_flash_setting *s = &fled_cdev->brightness;
+	u32 brightness;
+
+	if (has_flash_op(fled_cdev, flash_brightness_get)) {
+		int ret = call_flash_op(fled_cdev, flash_brightness_get,
+						&brightness);
+		if (ret < 0)
+			return ret;
+
+		s->val = brightness;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(led_update_flash_brightness);
+
+MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
+MODULE_DESCRIPTION("LED Flash class interface");
+MODULE_LICENSE("GPL v2");