linux/drivers/leds/led-core.c
Lee Jones d33d1214a1 leds: core: Omit set_brightness error message for a LED supporting hw trigger only
If both set_brightness functions return -ENOTSUPP, then the LED doesn't
support setting a fixed brightness value, and the error message isn't
helpful. This can be the case e.g. for LEDs supporting a specific hw
trigger only.

Pinched the subject line and commit message from Heiner:
Link: https://lore.kernel.org/all/44177e37-9512-4044-8991-bb23b184bf37@gmail.com/

Reworked the function to provide Heiner's required semantics whilst
simultaneously increasing readability and flow.

Cc: Pavel Machek <pavel@ucw.cz>
Cc: linux-leds@vger.kernel.org
Suggested-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Lee Jones <lee@kernel.org>
2024-06-26 16:55:44 +01:00

597 lines
16 KiB
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 = 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_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);
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)
{
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_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);
schedule_work(&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)
{
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, 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);
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, 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.
*/
if (value) {
led_cdev->delayed_set_value = 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);
}
schedule_work(&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;
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) {
strscpy(led_classdev_name, props.label,
LED_MAX_NAME_SIZE);
} else {
snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
devicename, props.label);
}
} else if (props.function || props.color_present) {
char tmp_buf[LED_MAX_NAME_SIZE];
if (props.func_enum_present) {
snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d",
props.color_present ? led_colors[props.color] : "",
props.function ?: "", props.func_enum);
} else {
snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s",
props.color_present ? led_colors[props.color] : "",
props.function ?: "");
}
if (init_data->devname_mandatory) {
snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
devicename, tmp_buf);
} else {
strscpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE);
}
} else if (init_data->default_label) {
if (!devicename) {
dev_err(dev, "Legacy LED naming requires devicename segment");
return -EINVAL;
}
snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
devicename, init_data->default_label);
} else if (is_of_node(fwnode)) {
strscpy(led_classdev_name, to_of_node(fwnode)->name,
LED_MAX_NAME_SIZE);
} else
return -EINVAL;
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);