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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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29d76dfa29
Some led hardware allows drivers to query the led state, and this patch adds a hook to let the led class take advantage of that information when available. Without this functionality, when access to the led hardware is not exclusive (i.e. firmware or hardware might change its state behind the kernel's back), reality goes out of sync with the led class' idea of what the led is doing, which is annoying at best. Behaviour for drivers that do not or cannot read the led status is unchanged. Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
195 lines
4.7 KiB
C
195 lines
4.7 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) 2005-2007 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/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/ctype.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 void led_update_brightness(struct led_classdev *led_cdev)
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{
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if (led_cdev->brightness_get)
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led_cdev->brightness = led_cdev->brightness_get(led_cdev);
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}
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static ssize_t led_brightness_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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ssize_t ret = 0;
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/* no lock needed for this */
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led_update_brightness(led_cdev);
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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 device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(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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size_t count = after - buf;
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if (*after && isspace(*after))
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count++;
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if (count == size) {
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ret = count;
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if (state == LED_OFF)
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led_trigger_remove(led_cdev);
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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 DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store);
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#ifdef CONFIG_LEDS_TRIGGERS
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static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
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#endif
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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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int rc;
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led_cdev->dev = device_create(leds_class, parent, 0, "%s",
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led_cdev->name);
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if (unlikely(IS_ERR(led_cdev->dev)))
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return PTR_ERR(led_cdev->dev);
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dev_set_drvdata(led_cdev->dev, led_cdev);
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/* register the attributes */
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rc = device_create_file(led_cdev->dev, &dev_attr_brightness);
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if (rc)
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goto err_out;
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/* add to the list of leds */
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down_write(&leds_list_lock);
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list_add_tail(&led_cdev->node, &leds_list);
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up_write(&leds_list_lock);
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led_update_brightness(led_cdev);
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#ifdef CONFIG_LEDS_TRIGGERS
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init_rwsem(&led_cdev->trigger_lock);
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rc = device_create_file(led_cdev->dev, &dev_attr_trigger);
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if (rc)
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goto err_out_led_list;
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led_trigger_set_default(led_cdev);
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#endif
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printk(KERN_INFO "Registered led device: %s\n",
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led_cdev->name);
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return 0;
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#ifdef CONFIG_LEDS_TRIGGERS
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err_out_led_list:
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device_remove_file(led_cdev->dev, &dev_attr_brightness);
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list_del(&led_cdev->node);
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#endif
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err_out:
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device_unregister(led_cdev->dev);
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return rc;
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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 unregister
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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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device_remove_file(led_cdev->dev, &dev_attr_brightness);
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#ifdef CONFIG_LEDS_TRIGGERS
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device_remove_file(led_cdev->dev, &dev_attr_trigger);
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down_write(&led_cdev->trigger_lock);
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if (led_cdev->trigger)
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led_trigger_set(led_cdev, NULL);
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up_write(&led_cdev->trigger_lock);
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#endif
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device_unregister(led_cdev->dev);
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down_write(&leds_list_lock);
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list_del(&led_cdev->node);
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up_write(&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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