Quelle  led-core.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * LED Class Core
 *
 * Copyright 2005-2006 Openedhand Ltd.
 *
 * Author: Richard Purdie <rpurdie@openedhand.com>
 */

#include <linux/kernel.h>
#include <linux/led-class-multicolor.h>
#include <linux/leds.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/property.h>
#include <linux/rwsem.h>
#include <linux/slab.h>
#include <uapi/linux/uleds.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 const char * const led_colors[LED_COLOR_ID_MAX] = {
 [LED_COLOR_ID_WHITE] = "white",
 [LED_COLOR_ID_RED] = "red",
 [LED_COLOR_ID_GREEN] = "green",
 [LED_COLOR_ID_BLUE] = "blue",
 [LED_COLOR_ID_AMBER] = "amber",
 [LED_COLOR_ID_VIOLET] = "violet",
 [LED_COLOR_ID_YELLOW] = "yellow",
 [LED_COLOR_ID_IR] = "ir",
 [LED_COLOR_ID_MULTI] = "multicolor",
 [LED_COLOR_ID_RGB] = "rgb",
 [LED_COLOR_ID_PURPLE] = "purple",
 [LED_COLOR_ID_ORANGE] = "orange",
 [LED_COLOR_ID_PINK] = "pink",
 [LED_COLOR_ID_CYAN] = "cyan",
 [LED_COLOR_ID_LIME] = "lime",
};

static int __led_set_brightness(struct led_classdev *led_cdev, unsigned int 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, unsigned int 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 = timer_container_of(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_set_brightness(struct led_classdev *led_cdev,
        unsigned int value)
{
 int ret;

 ret = __led_set_brightness(led_cdev, value);
 if (ret == -ENOTSUPP) {
  ret = __led_set_brightness_blocking(led_cdev, value);
  if (ret == -ENOTSUPP)
   /* No back-end support to set a fixed brightness value */
   return;
 }

 /* LED HW might have been unplugged, therefore don't warn */
 if (ret == -ENODEV && led_cdev->flags & LED_UNREGISTERING &&
     led_cdev->flags & LED_HW_PLUGGABLE)
  return;

 if (ret < 0)
  dev_err(led_cdev->dev,
   "Setting an LED's brightness failed (%d)\n", ret);
}

static void set_brightness_delayed(struct work_struct *ws)
{
 struct led_classdev *led_cdev =
  container_of(ws, struct led_classdev, set_brightness_work);

 if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
  led_stop_software_blink(led_cdev);
  set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags);
 }

 /*
 * Triggers may call led_set_brightness(LED_OFF),
 * led_set_brightness(LED_FULL) in quick succession to disable blinking
 * and turn the LED on. Both actions may have been scheduled to run
 * before this work item runs once. To make sure this works properly
 * handle LED_SET_BRIGHTNESS_OFF first.
 */
 if (test_and_clear_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags)) {
  set_brightness_delayed_set_brightness(led_cdev, LED_OFF);
  /*
 * The consecutives led_set_brightness(LED_OFF),
 * led_set_brightness(LED_FULL) could have been executed out of
 * order (LED_FULL first), if the work_flags has been set
 * between LED_SET_BRIGHTNESS_OFF and LED_SET_BRIGHTNESS of this
 * work. To avoid ending with the LED turned off, turn the LED
 * on again.
 */
  if (led_cdev->delayed_set_value != LED_OFF)
   set_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
 }

 if (test_and_clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags))
  set_brightness_delayed_set_brightness(led_cdev, led_cdev->delayed_set_value);

 if (test_and_clear_bit(LED_SET_BLINK, &led_cdev->work_flags)) {
  unsigned long delay_on = led_cdev->delayed_delay_on;
  unsigned long delay_off = led_cdev->delayed_delay_off;

  led_blink_set(led_cdev, &delay_on, &delay_off);
 }
}

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)
{
 timer_delete_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_blink_set_nosleep(struct led_classdev *led_cdev, unsigned long delay_on,
      unsigned long delay_off)
{
 /* If necessary delegate to a work queue task. */
 if (led_cdev->blink_set && led_cdev->brightness_set_blocking) {
  led_cdev->delayed_delay_on = delay_on;
  led_cdev->delayed_delay_off = delay_off;
  set_bit(LED_SET_BLINK, &led_cdev->work_flags);
  queue_work(led_cdev->wq, &led_cdev->set_brightness_work);
  return;
 }

 led_blink_set(led_cdev, &delay_on, &delay_off);
}
EXPORT_SYMBOL_GPL(led_blink_set_nosleep);

void led_stop_software_blink(struct led_classdev *led_cdev)
{
 timer_delete_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, unsigned int 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) {
   set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
   queue_work(led_cdev->wq, &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, unsigned int value)
{
 /* Use brightness_set op if available, it is guaranteed not to sleep */
 if (!__led_set_brightness(led_cdev, value))
  return;

 /*
 * Brightness setting can sleep, delegate it to a work queue task.
 * value 0 / LED_OFF is special, since it also disables hw-blinking
 * (sw-blink disable is handled in led_set_brightness()).
 * To avoid a hw-blink-disable getting lost when a second brightness
 * change is done immediately afterwards (before the work runs),
 * it uses a separate work_flag.
 */
 led_cdev->delayed_set_value = value;
 /* Ensure delayed_set_value is seen before work_flags modification */
 smp_mb__before_atomic();

 if (value)
  set_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
 else {
  clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
  clear_bit(LED_SET_BLINK, &led_cdev->work_flags);
  set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags);
 }

 queue_work(led_cdev->wq, &led_cdev->set_brightness_work);
}
EXPORT_SYMBOL_GPL(led_set_brightness_nopm);

void led_set_brightness_nosleep(struct led_classdev *led_cdev, unsigned int 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, unsigned int 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);

/*
 * This is a led-core function because just like led_set_brightness()
 * it is used in the kernel by e.g. triggers.
 */
void led_mc_set_brightness(struct led_classdev *led_cdev,
      unsigned int *intensity_value, unsigned int num_colors,
      unsigned int brightness)
{
 struct led_classdev_mc *mcled_cdev;
 unsigned int i;

 if (!(led_cdev->flags & LED_MULTI_COLOR)) {
  dev_err_once(led_cdev->dev, "error not a multi-color LED\n");
  return;
 }

 mcled_cdev = lcdev_to_mccdev(led_cdev);
 if (num_colors != mcled_cdev->num_colors) {
  dev_err_once(led_cdev->dev, "error num_colors mismatch %u != %u\n",
        num_colors, mcled_cdev->num_colors);
  return;
 }

 for (i = 0; i < mcled_cdev->num_colors; i++)
  mcled_cdev->subled_info[i].intensity = intensity_value[i];

 led_set_brightness(led_cdev, brightness);
}
EXPORT_SYMBOL_GPL(led_mc_set_brightness);

int led_update_brightness(struct led_classdev *led_cdev)
{
 int ret;

 if (led_cdev->brightness_get) {
  ret = led_cdev->brightness_get(led_cdev);
  if (ret < 0)
   return ret;

  led_cdev->brightness = ret;
 }

 return 0;
}
EXPORT_SYMBOL_GPL(led_update_brightness);

u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
{
 struct fwnode_handle *fwnode = led_cdev->dev->fwnode;
 u32 *pattern;
 int count;

 count = fwnode_property_count_u32(fwnode, "led-pattern");
 if (count < 0)
  return NULL;

 pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
 if (!pattern)
  return NULL;

 if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) {
  kfree(pattern);
  return NULL;
 }

 *size = count;

 return pattern;
}
EXPORT_SYMBOL_GPL(led_get_default_pattern);

/* 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);

static void led_parse_fwnode_props(struct device *dev,
       struct fwnode_handle *fwnode,
       struct led_properties *props)
{
 int ret;

 if (!fwnode)
  return;

 if (fwnode_property_present(fwnode, "label")) {
  ret = fwnode_property_read_string(fwnode, "label", &props->label);
  if (ret)
   dev_err(dev, "Error parsing 'label' property (%d)\n", ret);
  return;
 }

 if (fwnode_property_present(fwnode, "color")) {
  ret = fwnode_property_read_u32(fwnode, "color", &props->color);
  if (ret)
   dev_err(dev, "Error parsing 'color' property (%d)\n", ret);
  else if (props->color >= LED_COLOR_ID_MAX)
   dev_err(dev, "LED color identifier out of range\n");
  else
   props->color_present = true;
 }


 if (!fwnode_property_present(fwnode, "function"))
  return;

 ret = fwnode_property_read_string(fwnode, "function", &props->function);
 if (ret) {
  dev_err(dev,
   "Error parsing 'function' property (%d)\n",
   ret);
 }

 if (!fwnode_property_present(fwnode, "function-enumerator"))
  return;

 ret = fwnode_property_read_u32(fwnode, "function-enumerator",
           &props->func_enum);
 if (ret) {
  dev_err(dev,
   "Error parsing 'function-enumerator' property (%d)\n",
   ret);
 } else {
  props->func_enum_present = true;
 }
}

int led_compose_name(struct device *dev, struct led_init_data *init_data,
       char *led_classdev_name)
{
 struct led_properties props = {};
 struct fwnode_handle *fwnode = init_data->fwnode;
 const char *devicename = init_data->devicename;
 int n;

 if (!led_classdev_name)
  return -EINVAL;

 led_parse_fwnode_props(dev, fwnode, &props);

 if (props.label) {
  /*
 * If init_data.devicename is NULL, then it indicates that
 * DT label should be used as-is for LED class device name.
 * Otherwise the label is prepended with devicename to compose
 * the final LED class device name.
 */
  if (devicename) {
   n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
         devicename, props.label);
  } else {
   n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s", props.label);
  }
 } else if (props.function || props.color_present) {
  char tmp_buf[LED_MAX_NAME_SIZE];

  if (props.func_enum_present) {
   n = snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d",
         props.color_present ? led_colors[props.color] : "",
         props.function ?: "", props.func_enum);
  } else {
   n = snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s",
         props.color_present ? led_colors[props.color] : "",
         props.function ?: "");
  }
  if (n >= LED_MAX_NAME_SIZE)
   return -E2BIG;

  if (init_data->devname_mandatory) {
   n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
         devicename, tmp_buf);
  } else {
   n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s", tmp_buf);
  }
 } else if (init_data->default_label) {
  if (!devicename) {
   dev_err(dev, "Legacy LED naming requires devicename segment");
   return -EINVAL;
  }
  n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
        devicename, init_data->default_label);
 } else if (is_of_node(fwnode)) {
  n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s",
        to_of_node(fwnode)->name);
 } else
  return -EINVAL;

 if (n >= LED_MAX_NAME_SIZE)
  return -E2BIG;

 return 0;
}
EXPORT_SYMBOL_GPL(led_compose_name);

const char *led_get_color_name(u8 color_id)
{
 if (color_id >= ARRAY_SIZE(led_colors))
  return NULL;

 return led_colors[color_id];
}
EXPORT_SYMBOL_GPL(led_get_color_name);

enum led_default_state led_init_default_state_get(struct fwnode_handle *fwnode)
{
 const char *state = NULL;

 if (!fwnode_property_read_string(fwnode, "default-state", &state)) {
  if (!strcmp(state, "keep"))
   return LEDS_DEFSTATE_KEEP;
  if (!strcmp(state, "on"))
   return LEDS_DEFSTATE_ON;
 }

 return LEDS_DEFSTATE_OFF;
}
EXPORT_SYMBOL_GPL(led_init_default_state_get);