330 lines
8.7 KiB
C
330 lines
8.7 KiB
C
/*
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* LED Class Core
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*
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* Copyright 2005-2006 Openedhand Ltd.
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*
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* Author: 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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*/
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#include <linux/kernel.h>
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#include <linux/leds.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/rwsem.h>
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#include "leds.h"
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DECLARE_RWSEM(leds_list_lock);
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EXPORT_SYMBOL_GPL(leds_list_lock);
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LIST_HEAD(leds_list);
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EXPORT_SYMBOL_GPL(leds_list);
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static int __led_set_brightness(struct led_classdev *led_cdev,
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enum led_brightness value)
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{
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if (!led_cdev->brightness_set)
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return -ENOTSUPP;
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led_cdev->brightness_set(led_cdev, value);
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return 0;
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}
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static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
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enum led_brightness value)
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{
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if (!led_cdev->brightness_set_blocking)
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return -ENOTSUPP;
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return led_cdev->brightness_set_blocking(led_cdev, value);
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}
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static void led_timer_function(unsigned long data)
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{
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struct led_classdev *led_cdev = (void *)data;
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unsigned long brightness;
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unsigned long delay;
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if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
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led_set_brightness_nosleep(led_cdev, LED_OFF);
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clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
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return;
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}
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if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP,
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&led_cdev->work_flags)) {
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clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
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return;
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}
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brightness = led_get_brightness(led_cdev);
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if (!brightness) {
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/* Time to switch the LED on. */
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if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
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&led_cdev->work_flags))
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brightness = led_cdev->new_blink_brightness;
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else
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brightness = led_cdev->blink_brightness;
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delay = led_cdev->blink_delay_on;
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} else {
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/* Store the current brightness value to be able
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* to restore it when the delay_off period is over.
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*/
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led_cdev->blink_brightness = brightness;
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brightness = LED_OFF;
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delay = led_cdev->blink_delay_off;
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}
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led_set_brightness_nosleep(led_cdev, brightness);
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/* Return in next iteration if led is in one-shot mode and we are in
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* the final blink state so that the led is toggled each delay_on +
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* delay_off milliseconds in worst case.
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*/
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if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) {
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if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) {
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if (brightness)
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set_bit(LED_BLINK_ONESHOT_STOP,
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&led_cdev->work_flags);
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} else {
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if (!brightness)
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set_bit(LED_BLINK_ONESHOT_STOP,
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&led_cdev->work_flags);
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}
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}
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mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
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}
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static void set_brightness_delayed(struct work_struct *ws)
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{
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struct led_classdev *led_cdev =
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container_of(ws, struct led_classdev, set_brightness_work);
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int ret = 0;
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if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
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led_cdev->delayed_set_value = LED_OFF;
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led_stop_software_blink(led_cdev);
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}
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ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
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if (ret == -ENOTSUPP)
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ret = __led_set_brightness_blocking(led_cdev,
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led_cdev->delayed_set_value);
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if (ret < 0 &&
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/* LED HW might have been unplugged, therefore don't warn */
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!(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
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(led_cdev->flags & LED_HW_PLUGGABLE)))
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dev_err(led_cdev->dev,
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"Setting an LED's brightness failed (%d)\n", ret);
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}
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static void led_set_software_blink(struct led_classdev *led_cdev,
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unsigned long delay_on,
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unsigned long delay_off)
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{
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int current_brightness;
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current_brightness = led_get_brightness(led_cdev);
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if (current_brightness)
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led_cdev->blink_brightness = current_brightness;
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if (!led_cdev->blink_brightness)
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led_cdev->blink_brightness = led_cdev->max_brightness;
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led_cdev->blink_delay_on = delay_on;
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led_cdev->blink_delay_off = delay_off;
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/* never on - just set to off */
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if (!delay_on) {
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led_set_brightness_nosleep(led_cdev, LED_OFF);
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return;
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}
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/* never off - just set to brightness */
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if (!delay_off) {
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led_set_brightness_nosleep(led_cdev,
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led_cdev->blink_brightness);
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return;
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}
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set_bit(LED_BLINK_SW, &led_cdev->work_flags);
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mod_timer(&led_cdev->blink_timer, jiffies + 1);
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}
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static void led_blink_setup(struct led_classdev *led_cdev,
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unsigned long *delay_on,
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unsigned long *delay_off)
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{
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if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
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led_cdev->blink_set &&
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!led_cdev->blink_set(led_cdev, delay_on, delay_off))
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return;
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/* blink with 1 Hz as default if nothing specified */
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if (!*delay_on && !*delay_off)
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*delay_on = *delay_off = 500;
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led_set_software_blink(led_cdev, *delay_on, *delay_off);
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}
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void led_init_core(struct led_classdev *led_cdev)
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{
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INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
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setup_timer(&led_cdev->blink_timer, led_timer_function,
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(unsigned long)led_cdev);
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}
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EXPORT_SYMBOL_GPL(led_init_core);
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void led_blink_set(struct led_classdev *led_cdev,
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unsigned long *delay_on,
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unsigned long *delay_off)
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{
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del_timer_sync(&led_cdev->blink_timer);
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clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
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clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
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led_blink_setup(led_cdev, delay_on, delay_off);
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}
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EXPORT_SYMBOL_GPL(led_blink_set);
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void led_blink_set_oneshot(struct led_classdev *led_cdev,
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unsigned long *delay_on,
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unsigned long *delay_off,
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int invert)
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{
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if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
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timer_pending(&led_cdev->blink_timer))
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return;
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set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
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clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
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if (invert)
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set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
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else
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clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
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led_blink_setup(led_cdev, delay_on, delay_off);
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}
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EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
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void led_stop_software_blink(struct led_classdev *led_cdev)
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{
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del_timer_sync(&led_cdev->blink_timer);
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led_cdev->blink_delay_on = 0;
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led_cdev->blink_delay_off = 0;
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clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
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}
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EXPORT_SYMBOL_GPL(led_stop_software_blink);
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void led_set_brightness(struct led_classdev *led_cdev,
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enum led_brightness brightness)
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{
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/*
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* If software blink is active, delay brightness setting
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* until the next timer tick.
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*/
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if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
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/*
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* If we need to disable soft blinking delegate this to the
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* work queue task to avoid problems in case we are called
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* from hard irq context.
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*/
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if (brightness == LED_OFF) {
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set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
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schedule_work(&led_cdev->set_brightness_work);
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} else {
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set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
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&led_cdev->work_flags);
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led_cdev->new_blink_brightness = brightness;
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}
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return;
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}
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led_set_brightness_nosleep(led_cdev, brightness);
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}
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EXPORT_SYMBOL_GPL(led_set_brightness);
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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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{
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/* Use brightness_set op if available, it is guaranteed not to sleep */
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if (!__led_set_brightness(led_cdev, value))
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return;
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/* If brightness setting can sleep, delegate it to a work queue task */
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led_cdev->delayed_set_value = value;
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schedule_work(&led_cdev->set_brightness_work);
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}
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EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
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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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{
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led_cdev->brightness = min(value, led_cdev->max_brightness);
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if (led_cdev->flags & LED_SUSPENDED)
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return;
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led_set_brightness_nopm(led_cdev, led_cdev->brightness);
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}
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EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
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int led_set_brightness_sync(struct led_classdev *led_cdev,
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enum led_brightness value)
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{
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if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
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return -EBUSY;
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led_cdev->brightness = min(value, led_cdev->max_brightness);
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if (led_cdev->flags & LED_SUSPENDED)
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return 0;
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return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
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}
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EXPORT_SYMBOL_GPL(led_set_brightness_sync);
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int led_update_brightness(struct led_classdev *led_cdev)
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{
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int ret = 0;
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if (led_cdev->brightness_get) {
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ret = led_cdev->brightness_get(led_cdev);
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if (ret >= 0) {
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led_cdev->brightness = ret;
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return 0;
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}
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(led_update_brightness);
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/* Caller must ensure led_cdev->led_access held */
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void led_sysfs_disable(struct led_classdev *led_cdev)
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{
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lockdep_assert_held(&led_cdev->led_access);
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led_cdev->flags |= LED_SYSFS_DISABLE;
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}
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EXPORT_SYMBOL_GPL(led_sysfs_disable);
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/* Caller must ensure led_cdev->led_access held */
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void led_sysfs_enable(struct led_classdev *led_cdev)
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{
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lockdep_assert_held(&led_cdev->led_access);
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led_cdev->flags &= ~LED_SYSFS_DISABLE;
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}
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EXPORT_SYMBOL_GPL(led_sysfs_enable);
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