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![Akinobu Mita](/assets/img/avatar_default.png)
Reading /sys/class/leds/<led>/trigger returns all available LED triggers. However, the size of this file is limited to PAGE_SIZE because of the limitation for sysfs attribute. Enabling LED CPU trigger on systems with thousands of CPUs easily hits PAGE_SIZE limit, and makes it impossible to see all available LED triggers and which trigger is currently activated. We work around it here by converting /sys/class/leds/<led>/trigger to binary attribute, which is not limited by length. This is _not_ good design, do not copy it. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Dan Murphy <dmurphy@ti.com>A Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Pavel Machek <pavel@ucw.cz>
38 lines
1.1 KiB
C
38 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* LED Core
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*
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* Copyright 2005 Openedhand Ltd.
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*
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* Author: Richard Purdie <rpurdie@openedhand.com>
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*/
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#ifndef __LEDS_H_INCLUDED
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#define __LEDS_H_INCLUDED
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#include <linux/rwsem.h>
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#include <linux/leds.h>
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static inline int led_get_brightness(struct led_classdev *led_cdev)
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{
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return led_cdev->brightness;
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}
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void led_init_core(struct led_classdev *led_cdev);
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void led_stop_software_blink(struct led_classdev *led_cdev);
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void led_set_brightness_nopm(struct led_classdev *led_cdev,
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enum led_brightness value);
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void led_set_brightness_nosleep(struct led_classdev *led_cdev,
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enum led_brightness value);
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ssize_t led_trigger_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *attr, char *buf,
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loff_t pos, size_t count);
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ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf,
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loff_t pos, size_t count);
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extern struct rw_semaphore leds_list_lock;
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extern struct list_head leds_list;
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extern struct list_head trigger_list;
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extern const char * const led_colors[LED_COLOR_ID_MAX];
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#endif /* __LEDS_H_INCLUDED */
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