修改led-core.c 让led的delay_on和delay_off时间不会应为trigger配置改版而重置为1HZ

先列一下leds trigger的设置流程

echo none > trigger 的流程

led_trigger_set()
  |
  led_stop_software_blink()
    
echo timer > trigger 的流程
led_trigger_set()
  |
  ret = trig->activate(led_cdev);
    |
    timer_trig_activate()
      |
      led_blink_set()
        |
        led_blink_setup()
 
问题出在led_stop_software_blink()这个函数。当trigger设置为none时会调用到这里,这个函数会将delay_on/off都还原成0
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);
}

当trigger设置为timer时会调用到这里,此时delay_on跟delay_off都为0,if (!*delay_on && !*delay_off) 判断成立,最终delay_on/off就被重置为1HZ

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);
}

 

所以,解决方案就是将led_stop_software_blink()函数中delay_on/off设置为0的代码注释掉。

posted @ 2023-07-19 23:00  PYPYN  阅读(111)  评论(0编辑  收藏  举报