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// SPDX-License-Identifier: GPL-2.0-only
/*
* LED Triggers Core
*
* Copyright 2005-2007 Openedhand Ltd.
*
* Author: Richard Purdie <rpurdie@openedhand.com>
*/
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/timer.h>
#include <linux/rwsem.h>
#include <linux/leds.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include "leds.h"
/*
* Nests outside led_cdev->trigger_lock
*/
static DECLARE_RWSEM(triggers_list_lock);
static LIST_HEAD(trigger_list);
/* Used by LED Class */
static inline bool
trigger_relevant(struct led_classdev *led_cdev, struct led_trigger *trig)
{
return !trig->trigger_type || trig->trigger_type == led_cdev->trigger_type;
}
ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t pos, size_t count)
{
struct device *dev = kobj_to_dev(kobj);
struct led_classdev *led_cdev = dev_get_drvdata(dev);
struct led_trigger *trig;
int ret = count;
mutex_lock(&led_cdev->led_access);
if (led_sysfs_is_disabled(led_cdev)) {
ret = -EBUSY;
goto unlock;
}
if (sysfs_streq(buf, "none")) {
led_trigger_remove(led_cdev);
goto unlock;
}
down_read(&triggers_list_lock);
list_for_each_entry(trig, &trigger_list, next_trig) {
if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) {
down_write(&led_cdev->trigger_lock);
led_trigger_set(led_cdev, trig);
up_write(&led_cdev->trigger_lock);
up_read(&triggers_list_lock);
goto unlock;
}
}
/* we come here only if buf matches no trigger */
ret = -EINVAL;
up_read(&triggers_list_lock);
unlock:
mutex_unlock(&led_cdev->led_access);
return ret;
}
EXPORT_SYMBOL_GPL(led_trigger_write);
__printf(3, 4)
static int led_trigger_snprintf(char *buf, ssize_t size, const char *fmt, ...)
{
va_list args;
int i;
va_start(args, fmt);
if (size <= 0)
i = vsnprintf(NULL, 0, fmt, args);
else
i = vscnprintf(buf, size, fmt, args);
va_end(args);
return i;
}
static int led_trigger_format(char *buf, size_t size,
struct led_classdev *led_cdev)
{
struct led_trigger *trig;
int len = led_trigger_snprintf(buf, size, "%s",
led_cdev->trigger ? "none" : "[none]");
list_for_each_entry(trig, &trigger_list, next_trig) {
bool hit;
if (!trigger_relevant(led_cdev, trig))
continue;
hit = led_cdev->trigger && !strcmp(led_cdev->trigger->name, trig->name);
len += led_trigger_snprintf(buf + len, size - len,
" %s%s%s", hit ? "[" : "",
trig->name, hit ? "]" : "");
}
len += led_trigger_snprintf(buf + len, size - len, "\n");
return len;
}
/*
* It was stupid to create 10000 cpu triggers, but we are stuck with it now.
* Don't make that mistake again. We work around it here by creating binary
* attribute, which is not limited by length. This is _not_ good design, do not
* copy it.
*/
ssize_t led_trigger_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr, char *buf,
loff_t pos, size_t count)
{
struct device *dev = kobj_to_dev(kobj);
struct led_classdev *led_cdev = dev_get_drvdata(dev);
void *data;
int len;
down_read(&triggers_list_lock);
down_read(&led_cdev->trigger_lock);
len = led_trigger_format(NULL, 0, led_cdev);
data = kvmalloc(len + 1, GFP_KERNEL);
if (!data) {
up_read(&led_cdev->trigger_lock);
up_read(&triggers_list_lock);
return -ENOMEM;
}
len = led_trigger_format(data, len + 1, led_cdev);
up_read(&led_cdev->trigger_lock);
up_read(&triggers_list_lock);
len = memory_read_from_buffer(buf, count, &pos, data, len);
kvfree(data);
return len;
}
EXPORT_SYMBOL_GPL(led_trigger_read);
/* Caller must ensure led_cdev->trigger_lock held */
int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
{
char *event = NULL;
char *envp[2];
const char *name;
int ret;
if (!led_cdev->trigger && !trig)
return 0;
name = trig ? trig->name : "none";
event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
/* Remove any existing trigger */
if (led_cdev->trigger) {
spin_lock(&led_cdev->trigger->leddev_list_lock);
list_del_rcu(&led_cdev->trig_list);
spin_unlock(&led_cdev->trigger->leddev_list_lock);
/* ensure it's no longer visible on the led_cdevs list */
synchronize_rcu();
cancel_work_sync(&led_cdev->set_brightness_work);
led_stop_software_blink(led_cdev);
device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
if (led_cdev->trigger->deactivate)
led_cdev->trigger->deactivate(led_cdev);
led_cdev->trigger = NULL;
led_cdev->trigger_data = NULL;
led_cdev->activated = false;
led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
led_set_brightness(led_cdev, LED_OFF);
}
if (trig) {
spin_lock(&trig->leddev_list_lock);
list_add_tail_rcu(&led_cdev->trig_list, &trig->led_cdevs);
spin_unlock(&trig->leddev_list_lock);
led_cdev->trigger = trig;
/*
* Some activate() calls use led_trigger_event() to initialize
* the brightness of the LED for which the trigger is being set.
* Ensure the led_cdev is visible on trig->led_cdevs for this.
*/
synchronize_rcu();
/*
* If "set brightness to 0" is pending in workqueue,
* we don't want that to be reordered after ->activate()
*/
flush_work(&led_cdev->set_brightness_work);
ret = 0;
if (trig->activate)
ret = trig->activate(led_cdev);
else
led_set_brightness(led_cdev, trig->brightness);
if (ret)
goto err_activate;
ret = device_add_groups(led_cdev->dev, trig->groups);
if (ret) {
dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
goto err_add_groups;
}
}
if (event) {
envp[0] = event;
envp[1] = NULL;
if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
dev_err(led_cdev->dev,
"%s: Error sending uevent\n", __func__);
kfree(event);
}
return 0;
err_add_groups:
if (trig->deactivate)
trig->deactivate(led_cdev);
err_activate:
spin_lock(&led_cdev->trigger->leddev_list_lock);
list_del_rcu(&led_cdev->trig_list);
spin_unlock(&led_cdev->trigger->leddev_list_lock);
synchronize_rcu();
led_cdev->trigger = NULL;
led_cdev->trigger_data = NULL;
led_set_brightness(led_cdev, LED_OFF);
kfree(event);
return ret;
}
EXPORT_SYMBOL_GPL(led_trigger_set);
void led_trigger_remove(struct led_classdev *led_cdev)
{
down_write(&led_cdev->trigger_lock);
led_trigger_set(led_cdev, NULL);
up_write(&led_cdev->trigger_lock);
}
EXPORT_SYMBOL_GPL(led_trigger_remove);
static bool led_match_default_trigger(struct led_classdev *led_cdev,
struct led_trigger *trig)
{
if (!strcmp(led_cdev->default_trigger, trig->name) &&
trigger_relevant(led_cdev, trig)) {
led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
led_trigger_set(led_cdev, trig);
return true;
}
return false;
}
void led_trigger_set_default(struct led_classdev *led_cdev)
{
struct led_trigger *trig;
bool found = false;
if (!led_cdev->default_trigger)
return;
down_read(&triggers_list_lock);
down_write(&led_cdev->trigger_lock);
list_for_each_entry(trig, &trigger_list, next_trig) {
found = led_match_default_trigger(led_cdev, trig);
if (found)
break;
}
up_write(&led_cdev->trigger_lock);
up_read(&triggers_list_lock);
/*
* If default trigger wasn't found, maybe trigger module isn't loaded yet.
* Once loaded it will re-probe with all led_cdev's.
*/
if (!found)
request_module_nowait("ledtrig:%s", led_cdev->default_trigger);
}
EXPORT_SYMBOL_GPL(led_trigger_set_default);
/* LED Trigger Interface */
int led_trigger_register(struct led_trigger *trig)
{
struct led_classdev *led_cdev;
struct led_trigger *_trig;
spin_lock_init(&trig->leddev_list_lock);
INIT_LIST_HEAD(&trig->led_cdevs);
down_write(&triggers_list_lock);
/* Make sure the trigger's name isn't already in use */
list_for_each_entry(_trig, &trigger_list, next_trig) {
if (!strcmp(_trig->name, trig->name) &&
(trig->trigger_type == _trig->trigger_type ||
!trig->trigger_type || !_trig->trigger_type)) {
up_write(&triggers_list_lock);
return -EEXIST;
}
}
/* Add to the list of led triggers */
list_add_tail(&trig->next_trig, &trigger_list);
up_write(&triggers_list_lock);
/* Register with any LEDs that have this as a default trigger */
down_read(&leds_list_lock);
list_for_each_entry(led_cdev, &leds_list, node) {
down_write(&led_cdev->trigger_lock);
if (!led_cdev->trigger && led_cdev->default_trigger)
led_match_default_trigger(led_cdev, trig);
up_write(&led_cdev->trigger_lock);
}
up_read(&leds_list_lock);
return 0;
}
EXPORT_SYMBOL_GPL(led_trigger_register);
void led_trigger_unregister(struct led_trigger *trig)
{
struct led_classdev *led_cdev;
if (list_empty_careful(&trig->next_trig))
return;
/* Remove from the list of led triggers */
down_write(&triggers_list_lock);
list_del_init(&trig->next_trig);
up_write(&triggers_list_lock);
/* Remove anyone actively using this trigger */
down_read(&leds_list_lock);
list_for_each_entry(led_cdev, &leds_list, node) {
down_write(&led_cdev->trigger_lock);
if (led_cdev->trigger == trig)
led_trigger_set(led_cdev, NULL);
up_write(&led_cdev->trigger_lock);
}
up_read(&leds_list_lock);
}
EXPORT_SYMBOL_GPL(led_trigger_unregister);
static void devm_led_trigger_release(struct device *dev, void *res)
{
led_trigger_unregister(*(struct led_trigger **)res);
}
int devm_led_trigger_register(struct device *dev,
struct led_trigger *trig)
{
struct led_trigger **dr;
int rc;
dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
GFP_KERNEL);
if (!dr)
return -ENOMEM;
*dr = trig;
rc = led_trigger_register(trig);
if (rc)
devres_free(dr);
else
devres_add(dev, dr);
return rc;
}
EXPORT_SYMBOL_GPL(devm_led_trigger_register);
/* Simple LED Trigger Interface */
void led_trigger_event(struct led_trigger *trig,
enum led_brightness brightness)
{
struct led_classdev *led_cdev;
if (!trig)
return;
trig->brightness = brightness;
rcu_read_lock();
list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list)
led_set_brightness(led_cdev, brightness);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(led_trigger_event);
void led_mc_trigger_event(struct led_trigger *trig,
unsigned int *intensity_value, unsigned int num_colors,
enum led_brightness brightness)
{
struct led_classdev *led_cdev;
if (!trig)
return;
rcu_read_lock();
list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
if (!(led_cdev->flags & LED_MULTI_COLOR))
continue;
led_mc_set_brightness(led_cdev, intensity_value, num_colors, brightness);
}
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(led_mc_trigger_event);
static void led_trigger_blink_setup(struct led_trigger *trig,
unsigned long delay_on,
unsigned long delay_off,
int oneshot,
int invert)
{
struct led_classdev *led_cdev;
if (!trig)
return;
rcu_read_lock();
list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
if (oneshot)
led_blink_set_oneshot(led_cdev, &delay_on, &delay_off,
invert);
else
led_blink_set_nosleep(led_cdev, delay_on, delay_off);
}
rcu_read_unlock();
}
void led_trigger_blink(struct led_trigger *trig,
unsigned long delay_on,
unsigned long delay_off)
{
led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
}
EXPORT_SYMBOL_GPL(led_trigger_blink);
void led_trigger_blink_oneshot(struct led_trigger *trig,
unsigned long delay_on,
unsigned long delay_off,
int invert)
{
led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
}
EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
void led_trigger_register_simple(const char *name, struct led_trigger **tp)
{
struct led_trigger *trig;
int err;
trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
if (trig) {
trig->name = name;
err = led_trigger_register(trig);
if (err < 0) {
kfree(trig);
trig = NULL;
pr_warn("LED trigger %s failed to register (%d)\n",
name, err);
}
} else {
pr_warn("LED trigger %s failed to register (no memory)\n",
name);
}
*tp = trig;
}
EXPORT_SYMBOL_GPL(led_trigger_register_simple);
void led_trigger_unregister_simple(struct led_trigger *trig)
{
if (trig)
led_trigger_unregister(trig);
kfree(trig);
}
EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);