Commit 41c42ff5 authored by Luotao Fu's avatar Luotao Fu Committed by Richard Purdie

leds: simple driver for pwm driven LEDs

Add a simple driver for pwm driver LEDs.  pwm_id and period can be defined
in board file.  It is developed for pxa, however it is probably generic
enough to be used on other platforms with pwm.
Signed-off-by: default avatarLuotao Fu <l.fu@pengutronix.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarRichard Purdie <rpurdie@linux.intel.com>
parent b2bdc3e7
......@@ -197,6 +197,12 @@ config LEDS_DAC124S085
This option enables support for DAC124S085 SPI DAC from NatSemi,
which can be used to control up to four LEDs.
config LEDS_PWM
tristate "PWM driven LED Support"
depends on LEDS_CLASS && HAVE_PWM
help
This option enables support for pwm driven LEDs
comment "LED Triggers"
config LEDS_TRIGGERS
......
......@@ -24,6 +24,7 @@ obj-$(CONFIG_LEDS_FSG) += leds-fsg.o
obj-$(CONFIG_LEDS_PCA955X) += leds-pca955x.o
obj-$(CONFIG_LEDS_DA903X) += leds-da903x.o
obj-$(CONFIG_LEDS_WM8350) += leds-wm8350.o
obj-$(CONFIG_LEDS_PWM) += leds-pwm.o
# LED SPI Drivers
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
......
/*
* 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/fb.h>
#include <linux/leds.h>
#include <linux/err.h>
#include <linux/pwm.h>
#include <linux/leds_pwm.h>
struct led_pwm_data {
struct led_classdev cdev;
struct pwm_device *pwm;
unsigned int active_low;
unsigned int period;
unsigned int max_brightness;
};
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->max_brightness;
unsigned int period = led_dat->period;
if (brightness == 0) {
pwm_config(led_dat->pwm, 0, period);
pwm_disable(led_dat->pwm);
} else {
pwm_config(led_dat->pwm, brightness * period / max, period);
pwm_enable(led_dat->pwm);
}
}
static int led_pwm_probe(struct platform_device *pdev)
{
struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
struct led_pwm *cur_led;
struct led_pwm_data *leds_data, *led_dat;
int i, ret = 0;
if (!pdata)
return -EBUSY;
leds_data = kzalloc(sizeof(struct led_pwm_data) * pdata->num_leds,
GFP_KERNEL);
if (!leds_data)
return -ENOMEM;
for (i = 0; i < pdata->num_leds; i++) {
cur_led = &pdata->leds[i];
led_dat = &leds_data[i];
led_dat->pwm = pwm_request(cur_led->pwm_id,
cur_led->name);
if (IS_ERR(led_dat->pwm)) {
dev_err(&pdev->dev, "unable to request PWM %d\n",
cur_led->pwm_id);
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->max_brightness = cur_led->max_brightness;
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.flags |= LED_CORE_SUSPENDRESUME;
ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
if (ret < 0) {
pwm_free(led_dat->pwm);
goto err;
}
}
platform_set_drvdata(pdev, leds_data);
return 0;
err:
if (i > 0) {
for (i = i - 1; i >= 0; i--) {
led_classdev_unregister(&leds_data[i].cdev);
pwm_free(leds_data[i].pwm);
}
}
kfree(leds_data);
return ret;
}
static int __devexit led_pwm_remove(struct platform_device *pdev)
{
int i;
struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
struct led_pwm_data *leds_data;
leds_data = platform_get_drvdata(pdev);
for (i = 0; i < pdata->num_leds; i++) {
led_classdev_unregister(&leds_data[i].cdev);
pwm_free(leds_data[i].pwm);
}
kfree(leds_data);
return 0;
}
static struct platform_driver led_pwm_driver = {
.probe = led_pwm_probe,
.remove = __devexit_p(led_pwm_remove),
.driver = {
.name = "leds_pwm",
.owner = THIS_MODULE,
},
};
static int __init led_pwm_init(void)
{
return platform_driver_register(&led_pwm_driver);
}
static void __exit led_pwm_exit(void)
{
platform_driver_unregister(&led_pwm_driver);
}
module_init(led_pwm_init);
module_exit(led_pwm_exit);
MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
MODULE_DESCRIPTION("PWM LED driver for PXA");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-pwm");
/*
* PWM LED driver data - see drivers/leds/leds-pwm.c
*/
#ifndef __LINUX_LEDS_PWM_H
#define __LINUX_LEDS_PWM_H
struct led_pwm {
const char *name;
const char *default_trigger;
unsigned pwm_id;
u8 active_low;
unsigned max_brightness;
unsigned pwm_period_ns;
};
struct led_pwm_platform_data {
int num_leds;
struct led_pwm *leds;
};
#endif
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