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linux-next/drivers/leds/leds.h
Akinobu Mita 11f7000221 leds: remove PAGE_SIZE limit of /sys/class/leds/<led>/trigger
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>
2019-11-03 17:38:14 +01:00

39 lines
1.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* LED Core
*
* Copyright 2005 Openedhand Ltd.
*
* Author: Richard Purdie <rpurdie@openedhand.com>
*/
#ifndef __LEDS_H_INCLUDED
#define __LEDS_H_INCLUDED
#include <linux/rwsem.h>
#include <linux/leds.h>
static inline int led_get_brightness(struct led_classdev *led_cdev)
{
return led_cdev->brightness;
}
void led_init_core(struct led_classdev *led_cdev);
void led_stop_software_blink(struct led_classdev *led_cdev);
void led_set_brightness_nopm(struct led_classdev *led_cdev,
enum led_brightness value);
void led_set_brightness_nosleep(struct led_classdev *led_cdev,
enum led_brightness value);
ssize_t led_trigger_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr, char *buf,
loff_t pos, size_t count);
ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t pos, size_t count);
extern struct rw_semaphore leds_list_lock;
extern struct list_head leds_list;
extern struct list_head trigger_list;
extern const char * const led_colors[LED_COLOR_ID_MAX];
#endif /* __LEDS_H_INCLUDED */