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linux/drivers/leds/led-core.c
Jacek Anaszewski 7b6af2c531 leds: core: Fix regression caused by commit 2b83ff96f5 
Commit 2b83ff96f5 ("led: core: Fix brightness setting when setting delay_off=0")
replaced del_timer_sync(&led_cdev->blink_timer) with led_stop_software_blink()
in led_blink_set(), which additionally clears LED_BLINK_SW flag as well as
zeroes blink_delay_on and blink_delay_off properties of the struct led_classdev.

Cleansing of the latter ones wasn't required to fix the original issue but
wasn't considered harmful. It nonetheless turned out to be so in case when
pointer to one or both props is passed to led_blink_set() like in the
ledtrig-timer.c. In such cases zeroes are passed later in delay_on and/or
delay_off arguments to led_blink_setup(), which results either in stopping
the software blinking or setting blinking frequency always to 1Hz.

Avoid using led_stop_software_blink() and add a single call required
to clear LED_BLINK_SW flag, which was the only needed modification to
fix the original issue.

Fixes 2b83ff96f5 ("led: core: Fix brightness setting when setting delay_off=0")
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
2018-01-07 13:27:07 +01:00

330 lines
8.7 KiB
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/*
* 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/leds.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include "leds.h"
DECLARE_RWSEM(leds_list_lock);
EXPORT_SYMBOL_GPL(leds_list_lock);
LIST_HEAD(leds_list);
EXPORT_SYMBOL_GPL(leds_list);
static int __led_set_brightness(struct led_classdev *led_cdev,
enum led_brightness value)
{
if (!led_cdev->brightness_set)
return -ENOTSUPP;
led_cdev->brightness_set(led_cdev, value);
return 0;
}
static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
enum led_brightness value)
{
if (!led_cdev->brightness_set_blocking)
return -ENOTSUPP;
return led_cdev->brightness_set_blocking(led_cdev, value);
}
static void led_timer_function(struct timer_list *t)
{
struct led_classdev *led_cdev = from_timer(led_cdev, t, blink_timer);
unsigned long brightness;
unsigned long delay;
if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
led_set_brightness_nosleep(led_cdev, LED_OFF);
clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
return;
}
if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP,
&led_cdev->work_flags)) {
clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
return;
}
brightness = led_get_brightness(led_cdev);
if (!brightness) {
/* Time to switch the LED on. */
if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
&led_cdev->work_flags))
brightness = led_cdev->new_blink_brightness;
else
brightness = led_cdev->blink_brightness;
delay = led_cdev->blink_delay_on;
} else {
/* Store the current brightness value to be able
* to restore it when the delay_off period is over.
*/
led_cdev->blink_brightness = brightness;
brightness = LED_OFF;
delay = led_cdev->blink_delay_off;
}
led_set_brightness_nosleep(led_cdev, brightness);
/* Return in next iteration if led is in one-shot mode and we are in
* the final blink state so that the led is toggled each delay_on +
* delay_off milliseconds in worst case.
*/
if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) {
if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) {
if (brightness)
set_bit(LED_BLINK_ONESHOT_STOP,
&led_cdev->work_flags);
} else {
if (!brightness)
set_bit(LED_BLINK_ONESHOT_STOP,
&led_cdev->work_flags);
}
}
mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
}
static void set_brightness_delayed(struct work_struct *ws)
{
struct led_classdev *led_cdev =
container_of(ws, struct led_classdev, set_brightness_work);
int ret = 0;
if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
led_cdev->delayed_set_value = LED_OFF;
led_stop_software_blink(led_cdev);
}
ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
if (ret == -ENOTSUPP)
ret = __led_set_brightness_blocking(led_cdev,
led_cdev->delayed_set_value);
if (ret < 0 &&
/* LED HW might have been unplugged, therefore don't warn */
!(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
(led_cdev->flags & LED_HW_PLUGGABLE)))
dev_err(led_cdev->dev,
"Setting an LED's brightness failed (%d)\n", ret);
}
static void led_set_software_blink(struct led_classdev *led_cdev,
unsigned long delay_on,
unsigned long delay_off)
{
int current_brightness;
current_brightness = led_get_brightness(led_cdev);
if (current_brightness)
led_cdev->blink_brightness = current_brightness;
if (!led_cdev->blink_brightness)
led_cdev->blink_brightness = led_cdev->max_brightness;
led_cdev->blink_delay_on = delay_on;
led_cdev->blink_delay_off = delay_off;
/* never on - just set to off */
if (!delay_on) {
led_set_brightness_nosleep(led_cdev, LED_OFF);
return;
}
/* never off - just set to brightness */
if (!delay_off) {
led_set_brightness_nosleep(led_cdev,
led_cdev->blink_brightness);
return;
}
set_bit(LED_BLINK_SW, &led_cdev->work_flags);
mod_timer(&led_cdev->blink_timer, jiffies + 1);
}
static void led_blink_setup(struct led_classdev *led_cdev,
unsigned long *delay_on,
unsigned long *delay_off)
{
if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
led_cdev->blink_set &&
!led_cdev->blink_set(led_cdev, delay_on, delay_off))
return;
/* blink with 1 Hz as default if nothing specified */
if (!*delay_on && !*delay_off)
*delay_on = *delay_off = 500;
led_set_software_blink(led_cdev, *delay_on, *delay_off);
}
void led_init_core(struct led_classdev *led_cdev)
{
INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
timer_setup(&led_cdev->blink_timer, led_timer_function, 0);
}
EXPORT_SYMBOL_GPL(led_init_core);
void led_blink_set(struct led_classdev *led_cdev,
unsigned long *delay_on,
unsigned long *delay_off)
{
del_timer_sync(&led_cdev->blink_timer);
clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
led_blink_setup(led_cdev, delay_on, delay_off);
}
EXPORT_SYMBOL_GPL(led_blink_set);
void led_blink_set_oneshot(struct led_classdev *led_cdev,
unsigned long *delay_on,
unsigned long *delay_off,
int invert)
{
if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
timer_pending(&led_cdev->blink_timer))
return;
set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
if (invert)
set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
else
clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
led_blink_setup(led_cdev, delay_on, delay_off);
}
EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
void led_stop_software_blink(struct led_classdev *led_cdev)
{
del_timer_sync(&led_cdev->blink_timer);
led_cdev->blink_delay_on = 0;
led_cdev->blink_delay_off = 0;
clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
}
EXPORT_SYMBOL_GPL(led_stop_software_blink);
void led_set_brightness(struct led_classdev *led_cdev,
enum led_brightness brightness)
{
/*
* If software blink is active, delay brightness setting
* until the next timer tick.
*/
if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
/*
* If we need to disable soft blinking delegate this to the
* work queue task to avoid problems in case we are called
* from hard irq context.
*/
if (brightness == LED_OFF) {
set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
schedule_work(&led_cdev->set_brightness_work);
} else {
set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
&led_cdev->work_flags);
led_cdev->new_blink_brightness = brightness;
}
return;
}
led_set_brightness_nosleep(led_cdev, brightness);
}
EXPORT_SYMBOL_GPL(led_set_brightness);
void led_set_brightness_nopm(struct led_classdev *led_cdev,
enum led_brightness value)
{
/* Use brightness_set op if available, it is guaranteed not to sleep */
if (!__led_set_brightness(led_cdev, value))
return;
/* If brightness setting can sleep, delegate it to a work queue task */
led_cdev->delayed_set_value = value;
schedule_work(&led_cdev->set_brightness_work);
}
EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
void led_set_brightness_nosleep(struct led_classdev *led_cdev,
enum led_brightness value)
{
led_cdev->brightness = min(value, led_cdev->max_brightness);
if (led_cdev->flags & LED_SUSPENDED)
return;
led_set_brightness_nopm(led_cdev, led_cdev->brightness);
}
EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
int led_set_brightness_sync(struct led_classdev *led_cdev,
enum led_brightness value)
{
if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
return -EBUSY;
led_cdev->brightness = min(value, led_cdev->max_brightness);
if (led_cdev->flags & LED_SUSPENDED)
return 0;
return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
}
EXPORT_SYMBOL_GPL(led_set_brightness_sync);
int led_update_brightness(struct led_classdev *led_cdev)
{
int ret = 0;
if (led_cdev->brightness_get) {
ret = led_cdev->brightness_get(led_cdev);
if (ret >= 0) {
led_cdev->brightness = ret;
return 0;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(led_update_brightness);
/* Caller must ensure led_cdev->led_access held */
void led_sysfs_disable(struct led_classdev *led_cdev)
{
lockdep_assert_held(&led_cdev->led_access);
led_cdev->flags |= LED_SYSFS_DISABLE;
}
EXPORT_SYMBOL_GPL(led_sysfs_disable);
/* Caller must ensure led_cdev->led_access held */
void led_sysfs_enable(struct led_classdev *led_cdev)
{
lockdep_assert_held(&led_cdev->led_access);
led_cdev->flags &= ~LED_SYSFS_DISABLE;
}
EXPORT_SYMBOL_GPL(led_sysfs_enable);
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