linux/drivers/leds/led-class.c
Heiner Kallweit 66601a29bb leds: class: If no default trigger is given, make hw_control trigger the default trigger
If a hw_control_trigger is defined, it's usually desirable to make it
the default trigger. Therefore make it the default trigger, except
the driver explicitly set a default trigger.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/f33543de-3800-488f-a779-1fa282614462@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
2024-03-07 08:47:56 +00:00

690 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* LED Class Core
*
* Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
* Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
*/
#include <linux/ctype.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <uapi/linux/uleds.h>
#include <linux/of.h>
#include "leds.h"
static DEFINE_MUTEX(leds_lookup_lock);
static LIST_HEAD(leds_lookup_list);
static ssize_t brightness_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
/* no lock needed for this */
led_update_brightness(led_cdev);
return sprintf(buf, "%u\n", led_cdev->brightness);
}
static ssize_t brightness_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t size)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
unsigned long state;
ssize_t ret;
mutex_lock(&led_cdev->led_access);
if (led_sysfs_is_disabled(led_cdev)) {
ret = -EBUSY;
goto unlock;
}
ret = kstrtoul(buf, 10, &state);
if (ret)
goto unlock;
if (state == LED_OFF)
led_trigger_remove(led_cdev);
led_set_brightness(led_cdev, state);
flush_work(&led_cdev->set_brightness_work);
ret = size;
unlock:
mutex_unlock(&led_cdev->led_access);
return ret;
}
static DEVICE_ATTR_RW(brightness);
static ssize_t max_brightness_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
return sprintf(buf, "%u\n", led_cdev->max_brightness);
}
static DEVICE_ATTR_RO(max_brightness);
#ifdef CONFIG_LEDS_TRIGGERS
static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
static struct bin_attribute *led_trigger_bin_attrs[] = {
&bin_attr_trigger,
NULL,
};
static const struct attribute_group led_trigger_group = {
.bin_attrs = led_trigger_bin_attrs,
};
#endif
static struct attribute *led_class_attrs[] = {
&dev_attr_brightness.attr,
&dev_attr_max_brightness.attr,
NULL,
};
static const struct attribute_group led_group = {
.attrs = led_class_attrs,
};
static const struct attribute_group *led_groups[] = {
&led_group,
#ifdef CONFIG_LEDS_TRIGGERS
&led_trigger_group,
#endif
NULL,
};
#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
static ssize_t brightness_hw_changed_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
if (led_cdev->brightness_hw_changed == -1)
return -ENODATA;
return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
}
static DEVICE_ATTR_RO(brightness_hw_changed);
static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
{
struct device *dev = led_cdev->dev;
int ret;
ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
if (ret) {
dev_err(dev, "Error creating brightness_hw_changed\n");
return ret;
}
led_cdev->brightness_hw_changed_kn =
sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
if (!led_cdev->brightness_hw_changed_kn) {
dev_err(dev, "Error getting brightness_hw_changed kn\n");
device_remove_file(dev, &dev_attr_brightness_hw_changed);
return -ENXIO;
}
return 0;
}
static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
{
sysfs_put(led_cdev->brightness_hw_changed_kn);
device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
}
void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, unsigned int brightness)
{
if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
return;
led_cdev->brightness_hw_changed = brightness;
sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn);
}
EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
#else
static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
{
return 0;
}
static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
{
}
#endif
/**
* led_classdev_suspend - suspend an led_classdev.
* @led_cdev: the led_classdev to suspend.
*/
void led_classdev_suspend(struct led_classdev *led_cdev)
{
led_cdev->flags |= LED_SUSPENDED;
led_set_brightness_nopm(led_cdev, 0);
flush_work(&led_cdev->set_brightness_work);
}
EXPORT_SYMBOL_GPL(led_classdev_suspend);
/**
* led_classdev_resume - resume an led_classdev.
* @led_cdev: the led_classdev to resume.
*/
void led_classdev_resume(struct led_classdev *led_cdev)
{
led_set_brightness_nopm(led_cdev, led_cdev->brightness);
if (led_cdev->flash_resume)
led_cdev->flash_resume(led_cdev);
led_cdev->flags &= ~LED_SUSPENDED;
}
EXPORT_SYMBOL_GPL(led_classdev_resume);
#ifdef CONFIG_PM_SLEEP
static int led_suspend(struct device *dev)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
led_classdev_suspend(led_cdev);
return 0;
}
static int led_resume(struct device *dev)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
led_classdev_resume(led_cdev);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
static struct led_classdev *led_module_get(struct device *led_dev)
{
struct led_classdev *led_cdev;
if (!led_dev)
return ERR_PTR(-EPROBE_DEFER);
led_cdev = dev_get_drvdata(led_dev);
if (!try_module_get(led_cdev->dev->parent->driver->owner)) {
put_device(led_cdev->dev);
return ERR_PTR(-ENODEV);
}
return led_cdev;
}
static const struct class leds_class = {
.name = "leds",
.dev_groups = led_groups,
.pm = &leds_class_dev_pm_ops,
};
/**
* of_led_get() - request a LED device via the LED framework
* @np: device node to get the LED device from
* @index: the index of the LED
*
* Returns the LED device parsed from the phandle specified in the "leds"
* property of a device tree node or a negative error-code on failure.
*/
struct led_classdev *of_led_get(struct device_node *np, int index)
{
struct device *led_dev;
struct device_node *led_node;
led_node = of_parse_phandle(np, "leds", index);
if (!led_node)
return ERR_PTR(-ENOENT);
led_dev = class_find_device_by_of_node(&leds_class, led_node);
of_node_put(led_node);
put_device(led_dev);
return led_module_get(led_dev);
}
EXPORT_SYMBOL_GPL(of_led_get);
/**
* led_put() - release a LED device
* @led_cdev: LED device
*/
void led_put(struct led_classdev *led_cdev)
{
module_put(led_cdev->dev->parent->driver->owner);
put_device(led_cdev->dev);
}
EXPORT_SYMBOL_GPL(led_put);
static void devm_led_release(struct device *dev, void *res)
{
struct led_classdev **p = res;
led_put(*p);
}
static struct led_classdev *__devm_led_get(struct device *dev, struct led_classdev *led)
{
struct led_classdev **dr;
dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), GFP_KERNEL);
if (!dr) {
led_put(led);
return ERR_PTR(-ENOMEM);
}
*dr = led;
devres_add(dev, dr);
return led;
}
/**
* devm_of_led_get - Resource-managed request of a LED device
* @dev: LED consumer
* @index: index of the LED to obtain in the consumer
*
* The device node of the device is parse to find the request LED device.
* The LED device returned from this function is automatically released
* on driver detach.
*
* @return a pointer to a LED device or ERR_PTR(errno) on failure.
*/
struct led_classdev *__must_check devm_of_led_get(struct device *dev,
int index)
{
struct led_classdev *led;
if (!dev)
return ERR_PTR(-EINVAL);
led = of_led_get(dev->of_node, index);
if (IS_ERR(led))
return led;
return __devm_led_get(dev, led);
}
EXPORT_SYMBOL_GPL(devm_of_led_get);
/**
* led_get() - request a LED device via the LED framework
* @dev: device for which to get the LED device
* @con_id: name of the LED from the device's point of view
*
* @return a pointer to a LED device or ERR_PTR(errno) on failure.
*/
struct led_classdev *led_get(struct device *dev, char *con_id)
{
struct led_lookup_data *lookup;
const char *provider = NULL;
struct device *led_dev;
mutex_lock(&leds_lookup_lock);
list_for_each_entry(lookup, &leds_lookup_list, list) {
if (!strcmp(lookup->dev_id, dev_name(dev)) &&
!strcmp(lookup->con_id, con_id)) {
provider = kstrdup_const(lookup->provider, GFP_KERNEL);
break;
}
}
mutex_unlock(&leds_lookup_lock);
if (!provider)
return ERR_PTR(-ENOENT);
led_dev = class_find_device_by_name(&leds_class, provider);
kfree_const(provider);
return led_module_get(led_dev);
}
EXPORT_SYMBOL_GPL(led_get);
/**
* devm_led_get() - request a LED device via the LED framework
* @dev: device for which to get the LED device
* @con_id: name of the LED from the device's point of view
*
* The LED device returned from this function is automatically released
* on driver detach.
*
* @return a pointer to a LED device or ERR_PTR(errno) on failure.
*/
struct led_classdev *devm_led_get(struct device *dev, char *con_id)
{
struct led_classdev *led;
led = led_get(dev, con_id);
if (IS_ERR(led))
return led;
return __devm_led_get(dev, led);
}
EXPORT_SYMBOL_GPL(devm_led_get);
/**
* led_add_lookup() - Add a LED lookup table entry
* @led_lookup: the lookup table entry to add
*
* Add a LED lookup table entry. On systems without devicetree the lookup table
* is used by led_get() to find LEDs.
*/
void led_add_lookup(struct led_lookup_data *led_lookup)
{
mutex_lock(&leds_lookup_lock);
list_add_tail(&led_lookup->list, &leds_lookup_list);
mutex_unlock(&leds_lookup_lock);
}
EXPORT_SYMBOL_GPL(led_add_lookup);
/**
* led_remove_lookup() - Remove a LED lookup table entry
* @led_lookup: the lookup table entry to remove
*/
void led_remove_lookup(struct led_lookup_data *led_lookup)
{
mutex_lock(&leds_lookup_lock);
list_del(&led_lookup->list);
mutex_unlock(&leds_lookup_lock);
}
EXPORT_SYMBOL_GPL(led_remove_lookup);
/**
* devm_of_led_get_optional - Resource-managed request of an optional LED device
* @dev: LED consumer
* @index: index of the LED to obtain in the consumer
*
* The device node of the device is parsed to find the requested LED device.
* The LED device returned from this function is automatically released
* on driver detach.
*
* @return a pointer to a LED device, ERR_PTR(errno) on failure and NULL if the
* led was not found.
*/
struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
int index)
{
struct led_classdev *led;
led = devm_of_led_get(dev, index);
if (IS_ERR(led) && PTR_ERR(led) == -ENOENT)
return NULL;
return led;
}
EXPORT_SYMBOL_GPL(devm_of_led_get_optional);
static int led_classdev_next_name(const char *init_name, char *name,
size_t len)
{
unsigned int i = 0;
int ret = 0;
struct device *dev;
strscpy(name, init_name, len);
while ((ret < len) &&
(dev = class_find_device_by_name(&leds_class, name))) {
put_device(dev);
ret = snprintf(name, len, "%s_%u", init_name, ++i);
}
if (ret >= len)
return -ENOMEM;
return i;
}
/**
* led_classdev_register_ext - register a new object of led_classdev class
* with init data.
*
* @parent: parent of LED device
* @led_cdev: the led_classdev structure for this device.
* @init_data: LED class device initialization data
*/
int led_classdev_register_ext(struct device *parent,
struct led_classdev *led_cdev,
struct led_init_data *init_data)
{
char composed_name[LED_MAX_NAME_SIZE];
char final_name[LED_MAX_NAME_SIZE];
const char *proposed_name = composed_name;
int ret;
if (init_data) {
if (init_data->devname_mandatory && !init_data->devicename) {
dev_err(parent, "Mandatory device name is missing");
return -EINVAL;
}
ret = led_compose_name(parent, init_data, composed_name);
if (ret < 0)
return ret;
if (init_data->fwnode) {
fwnode_property_read_string(init_data->fwnode,
"linux,default-trigger",
&led_cdev->default_trigger);
if (fwnode_property_present(init_data->fwnode,
"retain-state-shutdown"))
led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
fwnode_property_read_u32(init_data->fwnode,
"max-brightness",
&led_cdev->max_brightness);
if (fwnode_property_present(init_data->fwnode, "color"))
fwnode_property_read_u32(init_data->fwnode, "color",
&led_cdev->color);
}
} else {
proposed_name = led_cdev->name;
}
ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
if (ret < 0)
return ret;
if (led_cdev->color >= LED_COLOR_ID_MAX)
dev_warn(parent, "LED %s color identifier out of range\n", final_name);
mutex_init(&led_cdev->led_access);
mutex_lock(&led_cdev->led_access);
led_cdev->dev = device_create_with_groups(&leds_class, parent, 0,
led_cdev, led_cdev->groups, "%s", final_name);
if (IS_ERR(led_cdev->dev)) {
mutex_unlock(&led_cdev->led_access);
return PTR_ERR(led_cdev->dev);
}
if (init_data && init_data->fwnode)
device_set_node(led_cdev->dev, init_data->fwnode);
if (ret)
dev_warn(parent, "Led %s renamed to %s due to name collision",
proposed_name, dev_name(led_cdev->dev));
if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
ret = led_add_brightness_hw_changed(led_cdev);
if (ret) {
device_unregister(led_cdev->dev);
led_cdev->dev = NULL;
mutex_unlock(&led_cdev->led_access);
return ret;
}
}
led_cdev->work_flags = 0;
#ifdef CONFIG_LEDS_TRIGGERS
init_rwsem(&led_cdev->trigger_lock);
#endif
#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
led_cdev->brightness_hw_changed = -1;
#endif
/* add to the list of leds */
down_write(&leds_list_lock);
list_add_tail(&led_cdev->node, &leds_list);
up_write(&leds_list_lock);
if (!led_cdev->max_brightness)
led_cdev->max_brightness = LED_FULL;
led_update_brightness(led_cdev);
led_init_core(led_cdev);
#ifdef CONFIG_LEDS_TRIGGERS
/*
* If no default trigger was given and hw_control_trigger is set,
* make it the default trigger.
*/
if (!led_cdev->default_trigger && led_cdev->hw_control_trigger)
led_cdev->default_trigger = led_cdev->hw_control_trigger;
led_trigger_set_default(led_cdev);
#endif
mutex_unlock(&led_cdev->led_access);
dev_dbg(parent, "Registered led device: %s\n",
led_cdev->name);
return 0;
}
EXPORT_SYMBOL_GPL(led_classdev_register_ext);
/**
* led_classdev_unregister - unregisters a object of led_properties class.
* @led_cdev: the led device to unregister
*
* Unregisters a previously registered via led_classdev_register object.
*/
void led_classdev_unregister(struct led_classdev *led_cdev)
{
if (IS_ERR_OR_NULL(led_cdev->dev))
return;
#ifdef CONFIG_LEDS_TRIGGERS
down_write(&led_cdev->trigger_lock);
if (led_cdev->trigger)
led_trigger_set(led_cdev, NULL);
up_write(&led_cdev->trigger_lock);
#endif
led_cdev->flags |= LED_UNREGISTERING;
/* Stop blinking */
led_stop_software_blink(led_cdev);
if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN))
led_set_brightness(led_cdev, LED_OFF);
flush_work(&led_cdev->set_brightness_work);
if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
led_remove_brightness_hw_changed(led_cdev);
device_unregister(led_cdev->dev);
down_write(&leds_list_lock);
list_del(&led_cdev->node);
up_write(&leds_list_lock);
mutex_destroy(&led_cdev->led_access);
}
EXPORT_SYMBOL_GPL(led_classdev_unregister);
static void devm_led_classdev_release(struct device *dev, void *res)
{
led_classdev_unregister(*(struct led_classdev **)res);
}
/**
* devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
*
* @parent: parent of LED device
* @led_cdev: the led_classdev structure for this device.
* @init_data: LED class device initialization data
*/
int devm_led_classdev_register_ext(struct device *parent,
struct led_classdev *led_cdev,
struct led_init_data *init_data)
{
struct led_classdev **dr;
int rc;
dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
if (!dr)
return -ENOMEM;
rc = led_classdev_register_ext(parent, led_cdev, init_data);
if (rc) {
devres_free(dr);
return rc;
}
*dr = led_cdev;
devres_add(parent, dr);
return 0;
}
EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
static int devm_led_classdev_match(struct device *dev, void *res, void *data)
{
struct led_classdev **p = res;
if (WARN_ON(!p || !*p))
return 0;
return *p == data;
}
/**
* devm_led_classdev_unregister() - resource managed led_classdev_unregister()
* @dev: The device to unregister.
* @led_cdev: the led_classdev structure for this device.
*/
void devm_led_classdev_unregister(struct device *dev,
struct led_classdev *led_cdev)
{
WARN_ON(devres_release(dev,
devm_led_classdev_release,
devm_led_classdev_match, led_cdev));
}
EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
static int __init leds_init(void)
{
return class_register(&leds_class);
}
static void __exit leds_exit(void)
{
class_unregister(&leds_class);
}
subsys_initcall(leds_init);
module_exit(leds_exit);
MODULE_AUTHOR("John Lenz, Richard Purdie");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LED Class Interface");