linux/drivers/leds/led-class.c
Jacek Anaszewski 7aea8389a7 leds: Add LED Flash class extension to the LED subsystem
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,
flash_sync_strobe and available_sync_leds. 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.anaszewski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2015-01-26 14:59:08 -08:00

312 lines
7.4 KiB
C

/*
* LED Class Core
*
* Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
* Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.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/ctype.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include "leds.h"
static struct class *leds_class;
static ssize_t brightness_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
/* no lock needed for this */
led_update_brightness(led_cdev);
return sprintf(buf, "%u\n", led_cdev->brightness);
}
static ssize_t brightness_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t size)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
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;
if (state == LED_OFF)
led_trigger_remove(led_cdev);
led_set_brightness(led_cdev, state);
ret = size;
unlock:
mutex_unlock(&led_cdev->led_access);
return ret;
}
static DEVICE_ATTR_RW(brightness);
static ssize_t max_brightness_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
return sprintf(buf, "%u\n", led_cdev->max_brightness);
}
static DEVICE_ATTR_RO(max_brightness);
#ifdef CONFIG_LEDS_TRIGGERS
static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
static struct attribute *led_trigger_attrs[] = {
&dev_attr_trigger.attr,
NULL,
};
static const struct attribute_group led_trigger_group = {
.attrs = led_trigger_attrs,
};
#endif
static struct attribute *led_class_attrs[] = {
&dev_attr_brightness.attr,
&dev_attr_max_brightness.attr,
NULL,
};
static const struct attribute_group led_group = {
.attrs = led_class_attrs,
};
static const struct attribute_group *led_groups[] = {
&led_group,
#ifdef CONFIG_LEDS_TRIGGERS
&led_trigger_group,
#endif
NULL,
};
static void led_timer_function(unsigned long data)
{
struct led_classdev *led_cdev = (void *)data;
unsigned long brightness;
unsigned long delay;
if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
led_set_brightness_async(led_cdev, LED_OFF);
return;
}
if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) {
led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
return;
}
brightness = led_get_brightness(led_cdev);
if (!brightness) {
/* Time to switch the LED on. */
brightness = led_cdev->blink_brightness;
delay = led_cdev->blink_delay_on;
} else {
/* Store the current brightness value to be able
* to restore it when the delay_off period is over.
*/
led_cdev->blink_brightness = brightness;
brightness = LED_OFF;
delay = led_cdev->blink_delay_off;
}
led_set_brightness_async(led_cdev, brightness);
/* Return in next iteration if led is in one-shot mode and we are in
* the final blink state so that the led is toggled each delay_on +
* delay_off milliseconds in worst case.
*/
if (led_cdev->flags & LED_BLINK_ONESHOT) {
if (led_cdev->flags & LED_BLINK_INVERT) {
if (brightness)
led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
} else {
if (!brightness)
led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
}
}
mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
}
static void set_brightness_delayed(struct work_struct *ws)
{
struct led_classdev *led_cdev =
container_of(ws, struct led_classdev, set_brightness_work);
led_stop_software_blink(led_cdev);
led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
}
/**
* led_classdev_suspend - suspend an led_classdev.
* @led_cdev: the led_classdev to suspend.
*/
void led_classdev_suspend(struct led_classdev *led_cdev)
{
led_cdev->flags |= LED_SUSPENDED;
led_cdev->brightness_set(led_cdev, 0);
}
EXPORT_SYMBOL_GPL(led_classdev_suspend);
/**
* led_classdev_resume - resume an led_classdev.
* @led_cdev: the led_classdev to resume.
*/
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);
static int led_suspend(struct device *dev)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
led_classdev_suspend(led_cdev);
return 0;
}
static int led_resume(struct device *dev)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
led_classdev_resume(led_cdev);
return 0;
}
static const struct dev_pm_ops leds_class_dev_pm_ops = {
.suspend = led_suspend,
.resume = led_resume,
};
/**
* led_classdev_register - register a new object of led_classdev class.
* @parent: The device to register.
* @led_cdev: the led_classdev structure for this device.
*/
int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
{
led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
led_cdev, led_cdev->groups,
"%s", led_cdev->name);
if (IS_ERR(led_cdev->dev))
return PTR_ERR(led_cdev->dev);
#ifdef CONFIG_LEDS_TRIGGERS
init_rwsem(&led_cdev->trigger_lock);
#endif
mutex_init(&led_cdev->led_access);
/* add to the list of leds */
down_write(&leds_list_lock);
list_add_tail(&led_cdev->node, &leds_list);
up_write(&leds_list_lock);
if (!led_cdev->max_brightness)
led_cdev->max_brightness = LED_FULL;
led_cdev->flags |= SET_BRIGHTNESS_ASYNC;
led_update_brightness(led_cdev);
INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
setup_timer(&led_cdev->blink_timer, led_timer_function,
(unsigned long)led_cdev);
#ifdef CONFIG_LEDS_TRIGGERS
led_trigger_set_default(led_cdev);
#endif
dev_dbg(parent, "Registered led device: %s\n",
led_cdev->name);
return 0;
}
EXPORT_SYMBOL_GPL(led_classdev_register);
/**
* led_classdev_unregister - unregisters a object of led_properties class.
* @led_cdev: the led device to unregister
*
* Unregisters a previously registered via led_classdev_register object.
*/
void led_classdev_unregister(struct led_classdev *led_cdev)
{
#ifdef CONFIG_LEDS_TRIGGERS
down_write(&led_cdev->trigger_lock);
if (led_cdev->trigger)
led_trigger_set(led_cdev, NULL);
up_write(&led_cdev->trigger_lock);
#endif
cancel_work_sync(&led_cdev->set_brightness_work);
/* Stop blinking */
led_stop_software_blink(led_cdev);
led_set_brightness(led_cdev, LED_OFF);
device_unregister(led_cdev->dev);
down_write(&leds_list_lock);
list_del(&led_cdev->node);
up_write(&leds_list_lock);
mutex_destroy(&led_cdev->led_access);
}
EXPORT_SYMBOL_GPL(led_classdev_unregister);
static int __init leds_init(void)
{
leds_class = class_create(THIS_MODULE, "leds");
if (IS_ERR(leds_class))
return PTR_ERR(leds_class);
leds_class->pm = &leds_class_dev_pm_ops;
leds_class->dev_groups = led_groups;
return 0;
}
static void __exit leds_exit(void)
{
class_destroy(leds_class);
}
subsys_initcall(leds_init);
module_exit(leds_exit);
MODULE_AUTHOR("John Lenz, Richard Purdie");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LED Class Interface");