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leds: Add of_led_get() and led_put()

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This patch adds basic support for a kernel driver to get a LED device.
This will be used by the led-backlight driver.

Only OF version is implemented for now, and the behavior is similar to
PWM's of_pwm_get() and pwm_put().

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
This commit is contained in:
Tomi Valkeinen 2019-10-03 10:28:09 +02:00 committed by Pavel
parent 31e065c4e8
commit 699a8c7c4b
2 changed files with 48 additions and 0 deletions
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44
drivers/leds/led-class.c
View File

@ -19,6 +19,7 @@
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <uapi/linux/uleds.h>
#include <linux/of.h>
#include "leds.h"
static struct class *leds_class;
@ -214,6 +215,49 @@ static int led_resume(struct device *dev)
static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
/**
* 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 led_classdev *led_cdev;
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);
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))
return ERR_PTR(-ENODEV);
return led_cdev;
}
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);
}
EXPORT_SYMBOL_GPL(led_put);
static int led_classdev_next_name(const char *init_name, char *name,
size_t len)
{

4
include/linux/leds.h
View File

@ -20,6 +20,7 @@
struct device;
struct led_pattern;
struct device_node;
/*
* LED Core
*/
@ -196,6 +197,9 @@ void devm_led_classdev_unregister(struct device *parent,
void led_classdev_suspend(struct led_classdev *led_cdev);
void led_classdev_resume(struct led_classdev *led_cdev);
extern struct led_classdev *of_led_get(struct device_node *np, int index);
extern void led_put(struct led_classdev *led_cdev);
/**
* led_blink_set - set blinking with software fallback
* @led_cdev: the LED to start blinking