linux/drivers/leds/leds-pwm.c
Olof Johansson 33fc94506b leds: pwm: Remove a warning on non-DT platforms
This removes a warning on non-DT-enabled platforms:

drivers/leds/leds-pwm.c: In function 'led_pwm_create_of':
drivers/leds/leds-pwm.c:88:22: warning: unused variable 'node'

Really caused by the local variable that is assigned to and then never
used. Just do away with the local var, it's not needed.

Technically this code path can never be entered without DT enabled,
since there's an earlier check about number of children in the calling
function, but the compiler can't see that.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2014-01-27 17:28:51 -08:00

245 lines
5.7 KiB
C

/*
* linux/drivers/leds-pwm.c
*
* simple PWM based LED control
*
* Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
*
* based on leds-gpio.c by Raphael Assenat <raph@8d.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/of_platform.h>
#include <linux/fb.h>
#include <linux/leds.h>
#include <linux/err.h>
#include <linux/pwm.h>
#include <linux/leds_pwm.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
struct led_pwm_data {
struct led_classdev cdev;
struct pwm_device *pwm;
struct work_struct work;
unsigned int active_low;
unsigned int period;
int duty;
bool can_sleep;
};
struct led_pwm_priv {
int num_leds;
struct led_pwm_data leds[0];
};
static void __led_pwm_set(struct led_pwm_data *led_dat)
{
int new_duty = led_dat->duty;
pwm_config(led_dat->pwm, new_duty, led_dat->period);
if (new_duty == 0)
pwm_disable(led_dat->pwm);
else
pwm_enable(led_dat->pwm);
}
static void led_pwm_work(struct work_struct *work)
{
struct led_pwm_data *led_dat =
container_of(work, struct led_pwm_data, work);
__led_pwm_set(led_dat);
}
static void led_pwm_set(struct led_classdev *led_cdev,
enum led_brightness brightness)
{
struct led_pwm_data *led_dat =
container_of(led_cdev, struct led_pwm_data, cdev);
unsigned int max = led_dat->cdev.max_brightness;
unsigned long long duty = led_dat->period;
duty *= brightness;
do_div(duty, max);
led_dat->duty = duty;
if (led_dat->can_sleep)
schedule_work(&led_dat->work);
else
__led_pwm_set(led_dat);
}
static inline size_t sizeof_pwm_leds_priv(int num_leds)
{
return sizeof(struct led_pwm_priv) +
(sizeof(struct led_pwm_data) * num_leds);
}
static int led_pwm_create_of(struct platform_device *pdev,
struct led_pwm_priv *priv)
{
struct device_node *child;
int ret;
for_each_child_of_node(pdev->dev.of_node, child) {
struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
led_dat->cdev.name = of_get_property(child, "label",
NULL) ? : child->name;
led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
if (IS_ERR(led_dat->pwm)) {
dev_err(&pdev->dev, "unable to request PWM for %s\n",
led_dat->cdev.name);
ret = PTR_ERR(led_dat->pwm);
goto err;
}
/* Get the period from PWM core when n*/
led_dat->period = pwm_get_period(led_dat->pwm);
led_dat->cdev.default_trigger = of_get_property(child,
"linux,default-trigger", NULL);
of_property_read_u32(child, "max-brightness",
&led_dat->cdev.max_brightness);
led_dat->cdev.brightness_set = led_pwm_set;
led_dat->cdev.brightness = LED_OFF;
led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
if (led_dat->can_sleep)
INIT_WORK(&led_dat->work, led_pwm_work);
ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register for %s\n",
led_dat->cdev.name);
of_node_put(child);
goto err;
}
priv->num_leds++;
}
return 0;
err:
while (priv->num_leds--)
led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
return ret;
}
static int led_pwm_probe(struct platform_device *pdev)
{
struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
struct led_pwm_priv *priv;
int count, i;
int ret = 0;
if (pdata)
count = pdata->num_leds;
else
count = of_get_child_count(pdev->dev.of_node);
if (!count)
return -EINVAL;
priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
GFP_KERNEL);
if (!priv)
return -ENOMEM;
if (pdata) {
for (i = 0; i < count; i++) {
struct led_pwm *cur_led = &pdata->leds[i];
struct led_pwm_data *led_dat = &priv->leds[i];
led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
if (IS_ERR(led_dat->pwm)) {
ret = PTR_ERR(led_dat->pwm);
dev_err(&pdev->dev,
"unable to request PWM for %s\n",
cur_led->name);
goto err;
}
led_dat->cdev.name = cur_led->name;
led_dat->cdev.default_trigger = cur_led->default_trigger;
led_dat->active_low = cur_led->active_low;
led_dat->period = cur_led->pwm_period_ns;
led_dat->cdev.brightness_set = led_pwm_set;
led_dat->cdev.brightness = LED_OFF;
led_dat->cdev.max_brightness = cur_led->max_brightness;
led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
if (led_dat->can_sleep)
INIT_WORK(&led_dat->work, led_pwm_work);
ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
if (ret < 0)
goto err;
}
priv->num_leds = count;
} else {
ret = led_pwm_create_of(pdev, priv);
if (ret)
return ret;
}
platform_set_drvdata(pdev, priv);
return 0;
err:
while (i--)
led_classdev_unregister(&priv->leds[i].cdev);
return ret;
}
static int led_pwm_remove(struct platform_device *pdev)
{
struct led_pwm_priv *priv = platform_get_drvdata(pdev);
int i;
for (i = 0; i < priv->num_leds; i++) {
led_classdev_unregister(&priv->leds[i].cdev);
if (priv->leds[i].can_sleep)
cancel_work_sync(&priv->leds[i].work);
}
return 0;
}
static const struct of_device_id of_pwm_leds_match[] = {
{ .compatible = "pwm-leds", },
{},
};
MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
static struct platform_driver led_pwm_driver = {
.probe = led_pwm_probe,
.remove = led_pwm_remove,
.driver = {
.name = "leds_pwm",
.owner = THIS_MODULE,
.of_match_table = of_pwm_leds_match,
},
};
module_platform_driver(led_pwm_driver);
MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
MODULE_DESCRIPTION("PWM LED driver for PXA");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-pwm");