leds: simple driver for pwm driven LEDs (41c42ff5) · Commits · e / devices / android_kernel_xiaomi_markw

drivers/leds/Kconfig

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	@@ -197,6 +197,12 @@ config LEDS_DAC124S085
	This option enables support for DAC124S085 SPI DAC from NatSemi,		This option enables support for DAC124S085 SPI DAC from NatSemi,
	which can be used to control up to four LEDs.		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"		comment "LED Triggers"

	config LEDS_TRIGGERS		config LEDS_TRIGGERS

drivers/leds/Makefile

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	@@ -24,6 +24,7 @@ obj-$(CONFIG_LEDS_FSG) += leds-fsg.o
	obj-$(CONFIG_LEDS_PCA955X) += leds-pca955x.o		obj-$(CONFIG_LEDS_PCA955X) += leds-pca955x.o
	obj-$(CONFIG_LEDS_DA903X) += leds-da903x.o		obj-$(CONFIG_LEDS_DA903X) += leds-da903x.o
	obj-$(CONFIG_LEDS_WM8350) += leds-wm8350.o		obj-$(CONFIG_LEDS_WM8350) += leds-wm8350.o
			obj-$(CONFIG_LEDS_PWM) += leds-pwm.o

	# LED SPI Drivers		# LED SPI Drivers
	obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o		obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o

drivers/leds/leds-pwm.c

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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>

			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

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			/*
			* 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