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c72a1d608d
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: Richard Purdie <rpurdie@rpsys.net> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
147 lines
3.7 KiB
C
147 lines
3.7 KiB
C
/*
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* LED Class Core
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*
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* Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
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* Copyright (C) 2005-2006 Richard Purdie <rpurdie@openedhand.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/device.h>
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#include <linux/sysdev.h>
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#include <linux/timer.h>
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#include <linux/err.h>
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#include <linux/leds.h>
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#include "leds.h"
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static struct class *leds_class;
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static ssize_t led_brightness_show(struct class_device *dev, char *buf)
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{
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struct led_classdev *led_cdev = class_get_devdata(dev);
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ssize_t ret = 0;
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/* no lock needed for this */
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sprintf(buf, "%u\n", led_cdev->brightness);
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ret = strlen(buf) + 1;
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return ret;
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}
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static ssize_t led_brightness_store(struct class_device *dev,
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const char *buf, size_t size)
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{
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struct led_classdev *led_cdev = class_get_devdata(dev);
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ssize_t ret = -EINVAL;
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char *after;
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unsigned long state = simple_strtoul(buf, &after, 10);
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if (after - buf > 0) {
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ret = after - buf;
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led_set_brightness(led_cdev, state);
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}
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return ret;
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}
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static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,
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led_brightness_store);
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/**
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* led_classdev_suspend - suspend an led_classdev.
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* @led_cdev: the led_classdev to suspend.
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*/
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void led_classdev_suspend(struct led_classdev *led_cdev)
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{
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led_cdev->flags |= LED_SUSPENDED;
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led_cdev->brightness_set(led_cdev, 0);
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}
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EXPORT_SYMBOL_GPL(led_classdev_suspend);
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/**
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* led_classdev_resume - resume an led_classdev.
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* @led_cdev: the led_classdev to resume.
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*/
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void led_classdev_resume(struct led_classdev *led_cdev)
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{
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led_cdev->brightness_set(led_cdev, led_cdev->brightness);
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led_cdev->flags &= ~LED_SUSPENDED;
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}
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EXPORT_SYMBOL_GPL(led_classdev_resume);
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/**
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* led_classdev_register - register a new object of led_classdev class.
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* @dev: The device to register.
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* @led_cdev: the led_classdev structure for this device.
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*/
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int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
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{
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led_cdev->class_dev = class_device_create(leds_class, NULL, 0,
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parent, "%s", led_cdev->name);
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if (unlikely(IS_ERR(led_cdev->class_dev)))
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return PTR_ERR(led_cdev->class_dev);
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class_set_devdata(led_cdev->class_dev, led_cdev);
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/* register the attributes */
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class_device_create_file(led_cdev->class_dev,
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&class_device_attr_brightness);
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/* add to the list of leds */
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write_lock(&leds_list_lock);
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list_add_tail(&led_cdev->node, &leds_list);
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write_unlock(&leds_list_lock);
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printk(KERN_INFO "Registered led device: %s\n",
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led_cdev->class_dev->class_id);
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return 0;
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}
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EXPORT_SYMBOL_GPL(led_classdev_register);
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/**
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* led_classdev_unregister - unregisters a object of led_properties class.
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* @led_cdev: the led device to unreigister
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*
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* Unregisters a previously registered via led_classdev_register object.
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*/
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void led_classdev_unregister(struct led_classdev *led_cdev)
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{
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class_device_remove_file(led_cdev->class_dev,
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&class_device_attr_brightness);
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class_device_unregister(led_cdev->class_dev);
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write_lock(&leds_list_lock);
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list_del(&led_cdev->node);
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write_unlock(&leds_list_lock);
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}
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EXPORT_SYMBOL_GPL(led_classdev_unregister);
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static int __init leds_init(void)
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{
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leds_class = class_create(THIS_MODULE, "leds");
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if (IS_ERR(leds_class))
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return PTR_ERR(leds_class);
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return 0;
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}
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static void __exit leds_exit(void)
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{
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class_destroy(leds_class);
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}
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subsys_initcall(leds_init);
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module_exit(leds_exit);
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MODULE_AUTHOR("John Lenz, Richard Purdie");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("LED Class Interface");
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