Message-ID: <20141203165013.GM14746@valkosipuli.retiisi.org.uk>
Date:	Wed, 3 Dec 2014 18:50:13 +0200
From:	Sakari Ailus <sakari.ailus@....fi>
To:	Jacek Anaszewski <j.anaszewski@...sung.com>
Cc:	linux-leds@...r.kernel.org, linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org, kyungmin.park@...sung.com,
	b.zolnierkie@...sung.com, pavel@....cz, cooloney@...il.com,
	rpurdie@...ys.net, s.nawrocki@...sung.com, robh+dt@...nel.org,
	pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org
Subject: Re: [PATCH/RFC v9 01/19] leds: Add LED Flash class extension to the
 LED subsystem

Hi Jacek,

Thanks for the update. A few comments below.

On Wed, Dec 03, 2014 at 05:06:36PM +0100, Jacek Anaszewski wrote:
> 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
> and flash_sync_strobe. All the flash related features are placed
> in a separate module. Torch mode is supported by the LED class
> interface.
> 
> 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.anaszewski@...sung.com>
> Acked-by: Kyungmin Park <kyungmin.park@...sung.com>
> Cc: Bryan Wu <cooloney@...il.com>
> Cc: Richard Purdie <rpurdie@...ys.net>
> ---
>  drivers/leds/Kconfig            |   10 +
>  drivers/leds/Makefile           |    1 +
>  drivers/leds/led-class-flash.c  |  446 +++++++++++++++++++++++++++++++++++++++
>  drivers/leds/led-class.c        |    4 +
>  include/linux/led-class-flash.h |  186 ++++++++++++++++
>  include/linux/leds.h            |    3 +
>  6 files changed, 650 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 b3c0d8a..fa8021e 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -19,6 +19,16 @@ 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
> +	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 1c65a19..cbba921 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..219b414
> --- /dev/null
> +++ b/drivers/leds/led-class-flash.c
> @@ -0,0 +1,446 @@
> +/*
> + * LED Flash class interface
> + *
> + * Copyright (C) 2014 Samsung Electronics Co., Ltd.
> + * Author: Jacek Anaszewski <j.anaszewski@...sung.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(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 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 ssize_t flash_sync_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 sync_strobe;
> +	ssize_t ret;
> +
> +	mutex_lock(&led_cdev->led_access);
> +
> +	if (led_sysfs_is_disabled(led_cdev)) {
> +		ret = -EBUSY;
> +		goto unlock;
> +	}
> +
> +	ret = kstrtoul(buf, 10, &sync_strobe);
> +	if (ret)
> +		goto unlock;
> +
> +	flash->sync_strobe = sync_strobe;
> +
> +	ret = size;
> +unlock:
> +	mutex_unlock(&led_cdev->led_access);
> +	return ret;
> +}
> +
> +static ssize_t flash_sync_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);
> +
> +	return sprintf(buf, "%u\n", flash->sync_strobe);
> +}
> +static DEVICE_ATTR_RW(flash_sync_strobe);
> +
> +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 struct attribute *led_flash_sync_strobe_attrs[] = {
> +	&dev_attr_flash_sync_strobe.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 const struct attribute_group led_flash_sync_strobe_group = {
> +	.attrs = led_flash_sync_strobe_attrs,
> +};
> +
> +static const struct attribute_group *flash_groups[] = {
> +	&led_flash_strobe_group,
> +	NULL,
> +	NULL,
> +	NULL,
> +	NULL,
> +	NULL,
> +	NULL
> +};
> +
> +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);
> +}
> +
> +static void led_flash_init_sysfs_groups(struct led_classdev_flash *flash)
> +{
> +	struct led_classdev *led_cdev = &flash->led_cdev;
> +	const struct led_flash_ops *ops = flash->ops;
> +	int num_sysfs_groups = 1;
> +
> +	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;
> +
> +	if (led_cdev->flags & LED_DEV_CAP_COMPOUND)
> +		flash_groups[num_sysfs_groups++] = &led_flash_sync_strobe_group;
> +
> +	led_cdev->groups = flash_groups;

Shouldn't you have groups local to the device instead? If you register
another flash device bad things will happen if the ops the device supports
are different.

> +}
> +
> +int led_classdev_flash_register(struct device *parent,
> +				struct led_classdev_flash *flash)
> +{
> +	struct led_classdev *led_cdev;
> +	const struct led_flash_ops *ops;
> +	int ret;
> +
> +	if (!flash)

Do you have a use case for this?

> +		return -EINVAL;
> +
> +	led_cdev = &flash->led_cdev;
> +
> +	if (led_cdev->flags & LED_DEV_CAP_FLASH) {
> +		if (!led_cdev->brightness_set_sync)
> +			return -EINVAL;
> +
> +		ops = flash->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(flash);
> +	}
> +
> +	/* Register led class device */
> +	ret = led_classdev_register(parent, led_cdev);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Setting a torch brightness needs to have immediate effect */
> +	led_cdev->flags &= ~SET_BRIGHTNESS_ASYNC;
> +	led_cdev->flags |= SET_BRIGHTNESS_SYNC;

I'm ok with making this a property of the device (rather than interface as I
originally thought it).

> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(led_classdev_flash_register);
> +
> +void led_classdev_flash_unregister(struct led_classdev_flash *flash)
> +{
> +	if (!flash)
> +		return;
> +
> +	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);

I'd instead have these in the header as static inline since they're just a
single function call, but up to you.

> +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;
> +
> +	s->val = timeout;
> +	led_clamp_align(s);
> +
> +	if (!(led_cdev->flags & LED_SUSPENDED))
> +		return call_flash_op(flash, timeout_set, s->val);
> +
> +	return 0;
> +}
> +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;
> +
> +	s->val = brightness;
> +	led_clamp_align(s);
> +
> +	if (!(led_cdev->flags & LED_SUSPENDED))
> +		return call_flash_op(flash, flash_brightness_set, s->val);
> +
> +	return 0;
> +}
> +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;
> +
> +	if (has_flash_op(flash, flash_brightness_get)) {
> +		int ret = call_flash_op(flash, 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@...sung.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 dbeebac..02564c5 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -179,6 +179,10 @@ 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..2043082
> --- /dev/null
> +++ b/include/linux/led-class-flash.h
> @@ -0,0 +1,186 @@
> +/*
> + * LED Flash class interface
> + *
> + * Copyright (C) 2014 Samsung Electronics Co., Ltd.
> + * Author: Jacek Anaszewski <j.anaszewski@...sung.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>
> +#include <uapi/linux/v4l2-controls.h>
> +
> +struct device_node;
> +struct led_classdev_flash;
> +
> +/*
> + * 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

V4L2_FLASH_FAULT_LED_OVER_TEMPERATURE

> +
> +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 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;
> +};
> +
> +struct led_classdev_flash {
> +	/* led class device */
> +	struct led_classdev led_cdev;
> +
> +	/* flash led specific ops */
> +	const struct led_flash_ops *ops;
> +
> +	/* flash brightness value in microamperes along with its constraints */
> +	struct led_flash_setting brightness;
> +
> +	/* flash timeout value in microseconds along with its constraints */
> +	struct led_flash_setting timeout;
> +
> +	/*
> +	 * Indicates whether the flash sub-led should strobe
> +	 * upon strobe activation on any of the remaining sub-leds.
> +	 */
> +	bool sync_strobe:1;
> +};
> +
> +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
> + *
> + * Returns: 0 on success or negative error value on failure
> + */
> +int led_classdev_flash_register(struct device *parent,
> +				struct led_classdev_flash *flash);
> +
> +/**
> + * led_classdev_flash_unregister - unregisters an object of led_classdev class
> + *				   with support for flash LEDs
> + * @flash: the flash LED to unregister
> + *
> + * Unregister 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
> + *
> + * Strobe the flash LED.
> + *
> + * 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.
> + *
> + * Returns: 0 on success or negative error value on failure
> + */
> +extern int led_get_flash_strobe(struct led_classdev_flash *flash,
> +				bool *state);

Fits on a single line. The same above.

> +
> +/**
> + * led_set_flash_brightness - set flash LED brightness
> + * @flash: the flash LED to set
> + * @brightness: the brightness to set it to
> + *
> + * Set a flash LED's brightness.
> + *
> + * Returns: 0 on success or negative error value on failure
> + */
> +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);
> +
> +#endif	/* __LINUX_FLASH_LEDS_H_INCLUDED */
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index cfceef3..c359f35 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -46,6 +46,8 @@ struct led_classdev {
>  #define LED_SYSFS_DISABLE	(1 << 20)
>  #define SET_BRIGHTNESS_ASYNC	(1 << 21)
>  #define SET_BRIGHTNESS_SYNC	(1 << 22)
> +#define LED_DEV_CAP_FLASH	(1 << 23)
> +#define LED_DEV_CAP_COMPOUND	(1 << 24)
>  
>  	/* Set LED brightness level */
>  	/* Must not sleep, use a workqueue if needed */
> @@ -81,6 +83,7 @@ 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;

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@....fi	XMPP: sailus@...iisi.org.uk
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