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/*
* 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>
#include <linux/slab.h>
struct led_pwm_data {
struct led_classdev cdev;
struct pwm_device *pwm;
unsigned int active_low;
unsigned int lth_brightness;
unsigned int period;
unsigned int dutycycle_steps;
unsigned int period_steps;
};
static int led_pwm_blink_set(struct led_classdev *led_cdev,
unsigned long *delay_on, unsigned long *delay_off)
{
struct led_pwm_data *led_dat =
container_of(led_cdev, struct led_pwm_data, cdev);
int dutycycle_ms, period_sec;
int dutycycle, period;
/*
* If both the delays are zero set some sensible delay
*/
if (*delay_on == 0 && *delay_off == 0) {
*delay_on = 500;
*delay_off = 500;
}
/*
* calculate the duty cycle from on and off time
*/
dutycycle_ms = ((*delay_on * 1000)/(*delay_on + *delay_off));
/*
* convert calculated value to write into the PWM out register
*/
if (led_dat->dutycycle_steps)
dutycycle = ((dutycycle_ms * led_dat->dutycycle_steps)/1000);
else
dutycycle = (dutycycle_ms/1000);
/*
* calculate period from on and off time(msec)
*/
period_sec = ((*delay_on + *delay_off)/1000);
/*
* convert calculated value to write into the PWM out register
*/
if (led_dat->period_steps) {
if ((*delay_on + *delay_off) == 500)
period = led_dat->period_steps;
else
period = led_dat->period_steps - period_sec;
}
else
period = period_sec;
/*
* configure the PWM registers and enable blink functionality
*/
pwm_config_blink(led_dat->pwm, dutycycle, period);
pwm_blink_ctrl(led_dat->pwm, 1);
return 0;
}
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 int period = led_dat->period;
if (brightness == 0) {
pwm_config(led_dat->pwm, 0, period);
pwm_disable(led_dat->pwm);
} else {
brightness = led_dat->lth_brightness + (brightness *
(led_dat->period - led_dat->lth_brightness) / max);
pwm_config(led_dat->pwm, brightness, led_dat->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)) {
ret = PTR_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->period = cur_led->pwm_period_ns;
led_dat->lth_brightness = cur_led->lth_brightness *
(cur_led->pwm_period_ns / cur_led->max_brightness);
led_dat->dutycycle_steps = cur_led->dutycycle_steps;
led_dat->period_steps = cur_led->period_steps;
led_dat->cdev.brightness_set = led_pwm_set;
led_dat->cdev.brightness = LED_OFF;
led_dat->cdev.blink_set = led_pwm_blink_set;
led_dat->cdev.max_brightness = cur_led->max_brightness;
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,
},
};
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");
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