Commit c72a1d60 authored by Richard Purdie's avatar Richard Purdie Committed by Linus Torvalds

[PATCH] LED: add LED class

Add the foundations of a new LEDs subsystem.  This patch adds a class which
presents LED devices within sysfs and allows their brightness to be
controlled.
Signed-off-by: default avatarRichard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 75c1d31d
......@@ -839,6 +839,8 @@ source "drivers/misc/Kconfig"
source "drivers/mfd/Kconfig"
source "drivers/leds/Kconfig"
source "drivers/media/Kconfig"
source "drivers/video/Kconfig"
......
......@@ -64,6 +64,8 @@ source "drivers/usb/Kconfig"
source "drivers/mmc/Kconfig"
source "drivers/leds/Kconfig"
source "drivers/infiniband/Kconfig"
source "drivers/sn/Kconfig"
......
......@@ -69,6 +69,7 @@ obj-$(CONFIG_MCA) += mca/
obj-$(CONFIG_EISA) += eisa/
obj-$(CONFIG_CPU_FREQ) += cpufreq/
obj-$(CONFIG_MMC) += mmc/
obj-$(CONFIG_NEW_LEDS) += leds/
obj-$(CONFIG_INFINIBAND) += infiniband/
obj-$(CONFIG_SGI_SN) += sn/
obj-y += firmware/
......
menu "LED devices"
config NEW_LEDS
bool "LED Support"
help
Say Y to enable Linux LED support. This is not related to standard
keyboard LEDs which are controlled via the input system.
config LEDS_CLASS
tristate "LED Class Support"
depends NEW_LEDS
help
This option enables the led sysfs class in /sys/class/leds. You'll
need this to do anything useful with LEDs. If unsure, say N.
endmenu
# LED Core
obj-$(CONFIG_NEW_LEDS) += led-core.o
obj-$(CONFIG_LEDS_CLASS) += led-class.o
/*
* LED Class Core
*
* Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
* Copyright (C) 2005-2006 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/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/sysdev.h>
#include <linux/timer.h>
#include <linux/err.h>
#include <linux/leds.h>
#include "leds.h"
static struct class *leds_class;
static ssize_t led_brightness_show(struct class_device *dev, char *buf)
{
struct led_classdev *led_cdev = class_get_devdata(dev);
ssize_t ret = 0;
/* no lock needed for this */
sprintf(buf, "%u\n", led_cdev->brightness);
ret = strlen(buf) + 1;
return ret;
}
static ssize_t led_brightness_store(struct class_device *dev,
const char *buf, size_t size)
{
struct led_classdev *led_cdev = class_get_devdata(dev);
ssize_t ret = -EINVAL;
char *after;
unsigned long state = simple_strtoul(buf, &after, 10);
if (after - buf > 0) {
ret = after - buf;
led_set_brightness(led_cdev, state);
}
return ret;
}
static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,
led_brightness_store);
/**
* 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);
led_cdev->flags &= ~LED_SUSPENDED;
}
EXPORT_SYMBOL_GPL(led_classdev_resume);
/**
* led_classdev_register - register a new object of led_classdev class.
* @dev: 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->class_dev = class_device_create(leds_class, NULL, 0,
parent, "%s", led_cdev->name);
if (unlikely(IS_ERR(led_cdev->class_dev)))
return PTR_ERR(led_cdev->class_dev);
class_set_devdata(led_cdev->class_dev, led_cdev);
/* register the attributes */
class_device_create_file(led_cdev->class_dev,
&class_device_attr_brightness);
/* add to the list of leds */
write_lock(&leds_list_lock);
list_add_tail(&led_cdev->node, &leds_list);
write_unlock(&leds_list_lock);
printk(KERN_INFO "Registered led device: %s\n",
led_cdev->class_dev->class_id);
return 0;
}
EXPORT_SYMBOL_GPL(led_classdev_register);
/**
* led_classdev_unregister - unregisters a object of led_properties class.
* @led_cdev: the led device to unreigister
*
* Unregisters a previously registered via led_classdev_register object.
*/
void led_classdev_unregister(struct led_classdev *led_cdev)
{
class_device_remove_file(led_cdev->class_dev,
&class_device_attr_brightness);
class_device_unregister(led_cdev->class_dev);
write_lock(&leds_list_lock);
list_del(&led_cdev->node);
write_unlock(&leds_list_lock);
}
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);
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");
/*
* LED Class Core
*
* Copyright 2005-2006 Openedhand Ltd.
*
* Author: 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/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/leds.h>
#include "leds.h"
rwlock_t leds_list_lock = RW_LOCK_UNLOCKED;
LIST_HEAD(leds_list);
EXPORT_SYMBOL_GPL(leds_list);
EXPORT_SYMBOL_GPL(leds_list_lock);
/*
* LED Core
*
* Copyright 2005 Openedhand Ltd.
*
* Author: 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.
*
*/
#ifndef __LEDS_H_INCLUDED
#define __LEDS_H_INCLUDED
#include <linux/leds.h>
static inline void led_set_brightness(struct led_classdev *led_cdev,
enum led_brightness value)
{
if (value > LED_FULL)
value = LED_FULL;
led_cdev->brightness = value;
if (!(led_cdev->flags & LED_SUSPENDED))
led_cdev->brightness_set(led_cdev, value);
}
extern rwlock_t leds_list_lock;
extern struct list_head leds_list;
#endif /* __LEDS_H_INCLUDED */
/*
* Driver model for leds and led triggers
*
* Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
* Copyright (C) 2005 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.
*
*/
#ifndef __LINUX_LEDS_H_INCLUDED
#define __LINUX_LEDS_H_INCLUDED
struct device;
struct class_device;
/*
* LED Core
*/
enum led_brightness {
LED_OFF = 0,
LED_HALF = 127,
LED_FULL = 255,
};
struct led_classdev {
const char *name;
int brightness;
int flags;
#define LED_SUSPENDED (1 << 0)
/* A function to set the brightness of the led */
void (*brightness_set)(struct led_classdev *led_cdev,
enum led_brightness brightness);
struct class_device *class_dev;
/* LED Device linked list */
struct list_head node;
/* Trigger data */
char *default_trigger;
};
extern int led_classdev_register(struct device *parent,
struct led_classdev *led_cdev);
extern void led_classdev_unregister(struct led_classdev *led_cdev);
extern void led_classdev_suspend(struct led_classdev *led_cdev);
extern void led_classdev_resume(struct led_classdev *led_cdev);
#endif /* __LINUX_LEDS_H_INCLUDED */
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