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

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

drivers/leds/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -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

drivers/leds/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/leds/leds-pwm.c

0 → 100644
+153 −0
Original line number Diff line number Diff line 
/*

 * 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");

include/linux/leds_pwm.h

0 → 100644
+21 −0
Original line number Diff line number Diff line 
/*

 * 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