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Commit d4cc6a2e authored by Antonio Ospite's avatar Antonio Ospite Committed by Richard Purdie
Browse files

leds: Add LED class driver for regulator driven LEDs. 



This driver provides an interface for controlling LEDs (or vibrators)
connected to PMICs for which there is a regulator framework driver.

This driver can be used, for instance, to control vibrator on all Motorola EZX
phones using the pcap-regulator driver services.

Signed-off-by: default avatarAntonio Ospite <ospite@studenti.unina.it>
Reviewed-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: default avatarRichard Purdie <rpurdie@linux.intel.com>
parent 3c0f6e1e

drivers/leds/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -229,6 +229,12 @@ config LEDS_PWM 
	help

	  This option enables support for pwm driven LEDs



config LEDS_REGULATOR

	tristate "REGULATOR driven LED support"

	depends on LEDS_CLASS && REGULATOR

	help

	  This option enables support for regulator driven LEDs.



config LEDS_BD2802

	tristate "LED driver for BD2802 RGB LED"

	depends on LEDS_CLASS && I2C

drivers/leds/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ obj-$(CONFIG_LEDS_DA903X) += leds-da903x.o 
obj-$(CONFIG_LEDS_WM831X_STATUS)	+= leds-wm831x-status.o

obj-$(CONFIG_LEDS_WM8350)		+= leds-wm8350.o

obj-$(CONFIG_LEDS_PWM)			+= leds-pwm.o

obj-$(CONFIG_LEDS_REGULATOR)		+= leds-regulator.o

obj-$(CONFIG_LEDS_INTEL_SS4200)		+= leds-ss4200.o

obj-$(CONFIG_LEDS_LT3593)		+= leds-lt3593.o

obj-$(CONFIG_LEDS_ADP5520)		+= leds-adp5520.o

drivers/leds/leds-regulator.c

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+242 −0
Original line number Diff line number Diff line 
/*

 * leds-regulator.c - LED class driver for regulator driven LEDs.

 *

 * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>

 *

 * Inspired by leds-wm8350 driver.

 *

 * 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/err.h>

#include <linux/workqueue.h>

#include <linux/leds.h>

#include <linux/leds-regulator.h>

#include <linux/platform_device.h>

#include <linux/regulator/consumer.h>



#define to_regulator_led(led_cdev) \

	container_of(led_cdev, struct regulator_led, cdev)



struct regulator_led {

	struct led_classdev cdev;

	enum led_brightness value;

	int enabled;

	struct mutex mutex;

	struct work_struct work;



	struct regulator *vcc;

};



static inline int led_regulator_get_max_brightness(struct regulator *supply)

{

	int ret;

	int voltage = regulator_list_voltage(supply, 0);



	if (voltage <= 0)

		return 1;



	/* even if regulator can't change voltages,

	 * we still assume it can change status

	 * and the LED can be turned on and off.

	 */

	ret = regulator_set_voltage(supply, voltage, voltage);

	if (ret < 0)

		return 1;



	return regulator_count_voltages(supply);

}



static int led_regulator_get_voltage(struct regulator *supply,

		enum led_brightness brightness)

{

	if (brightness == 0)

		return -EINVAL;



	return regulator_list_voltage(supply, brightness - 1);

}





static void regulator_led_enable(struct regulator_led *led)

{

	int ret;



	if (led->enabled)

		return;



	ret = regulator_enable(led->vcc);

	if (ret != 0) {

		dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret);

		return;

	}



	led->enabled = 1;

}



static void regulator_led_disable(struct regulator_led *led)

{

	int ret;



	if (!led->enabled)

		return;



	ret = regulator_disable(led->vcc);

	if (ret != 0) {

		dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret);

		return;

	}



	led->enabled = 0;

}



static void regulator_led_set_value(struct regulator_led *led)

{

	int voltage;

	int ret;



	mutex_lock(&led->mutex);



	if (led->value == LED_OFF) {

		regulator_led_disable(led);

		goto out;

	}



	if (led->cdev.max_brightness > 1) {

		voltage = led_regulator_get_voltage(led->vcc, led->value);

		dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n",

				led->value, voltage);



		ret = regulator_set_voltage(led->vcc, voltage, voltage);

		if (ret != 0)

			dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n",

				voltage, ret);

	}



	regulator_led_enable(led);



out:

	mutex_unlock(&led->mutex);

}



static void led_work(struct work_struct *work)

{

	struct regulator_led *led;



	led = container_of(work, struct regulator_led, work);

	regulator_led_set_value(led);

}



static void regulator_led_brightness_set(struct led_classdev *led_cdev,

			   enum led_brightness value)

{

	struct regulator_led *led = to_regulator_led(led_cdev);



	led->value = value;

	schedule_work(&led->work);

}



static int __devinit regulator_led_probe(struct platform_device *pdev)

{

	struct led_regulator_platform_data *pdata = pdev->dev.platform_data;

	struct regulator_led *led;

	struct regulator *vcc;

	int ret = 0;



	if (pdata == NULL) {

		dev_err(&pdev->dev, "no platform data\n");

		return -ENODEV;

	}



	vcc = regulator_get_exclusive(&pdev->dev, "vled");

	if (IS_ERR(vcc)) {

		dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name);

		return PTR_ERR(vcc);

	}



	led = kzalloc(sizeof(*led), GFP_KERNEL);

	if (led == NULL) {

		ret = -ENOMEM;

		goto err_vcc;

	}



	led->cdev.max_brightness = led_regulator_get_max_brightness(vcc);

	if (pdata->brightness > led->cdev.max_brightness) {

		dev_err(&pdev->dev, "Invalid default brightness %d\n",

				pdata->brightness);

		ret = -EINVAL;

		goto err_led;

	}

	led->value = pdata->brightness;



	led->cdev.brightness_set = regulator_led_brightness_set;

	led->cdev.name = pdata->name;

	led->cdev.flags |= LED_CORE_SUSPENDRESUME;

	led->vcc = vcc;



	mutex_init(&led->mutex);

	INIT_WORK(&led->work, led_work);



	platform_set_drvdata(pdev, led);



	ret = led_classdev_register(&pdev->dev, &led->cdev);

	if (ret < 0) {

		cancel_work_sync(&led->work);

		goto err_led;

	}



	/* to expose the default value to userspace */

	led->cdev.brightness = led->value;



	/* Set the default led status */

	regulator_led_set_value(led);



	return 0;



err_led:

	kfree(led);

err_vcc:

	regulator_put(vcc);

	return ret;

}



static int __devexit regulator_led_remove(struct platform_device *pdev)

{

	struct regulator_led *led = platform_get_drvdata(pdev);



	led_classdev_unregister(&led->cdev);

	cancel_work_sync(&led->work);

	regulator_led_disable(led);

	regulator_put(led->vcc);

	kfree(led);

	return 0;

}



static struct platform_driver regulator_led_driver = {

	.driver = {

		   .name  = "leds-regulator",

		   .owner = THIS_MODULE,

		   },

	.probe  = regulator_led_probe,

	.remove = __devexit_p(regulator_led_remove),

};



static int __init regulator_led_init(void)

{

	return platform_driver_register(&regulator_led_driver);

}

module_init(regulator_led_init);



static void __exit regulator_led_exit(void)

{

	platform_driver_unregister(&regulator_led_driver);

}

module_exit(regulator_led_exit);



MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");

MODULE_DESCRIPTION("Regulator driven LED driver");

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:leds-regulator");

include/linux/leds-regulator.h

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Original line number Diff line number Diff line 
/*

 * leds-regulator.h - platform data structure for regulator driven LEDs.

 *

 * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>

 *

 * 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.

 *

 */



#ifndef __LINUX_LEDS_REGULATOR_H

#define __LINUX_LEDS_REGULATOR_H



/*

 * Use "vled" as supply id when declaring the regulator consumer:

 *

 * static struct regulator_consumer_supply pcap_regulator_VVIB_consumers [] = {

 * 	{ .dev_name = "leds-regulator.0", supply = "vled" },

 * };

 *

 * If you have several regulator driven LEDs, you can append a numerical id to

 * .dev_name as done above, and use the same id when declaring the platform

 * device:

 *

 * static struct led_regulator_platform_data a780_vibrator_data = {

 * 	.name   = "a780::vibrator",

 * };

 *

 * static struct platform_device a780_vibrator = {

 * 	.name = "leds-regulator",

 * 	.id   = 0,

 * 	.dev  = {

 * 		.platform_data = &a780_vibrator_data,

 * 	},

 * };

 */



#include <linux/leds.h>



struct led_regulator_platform_data {

	char *name;                     /* LED name as expected by LED class */

	enum led_brightness brightness; /* initial brightness value */

};



#endif /* __LINUX_LEDS_REGULATOR_H */