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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
authored by
Luotao Fu
and committed by
Richard Purdie
41c42ff5
b2bdc3e7
+181
+6
drivers/leds/Kconfig
+6
drivers/leds/Kconfig
···
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This option enables support for DAC124S085 SPI DAC from NatSemi,
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which can be used to control up to four LEDs.
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config LEDS_PWM
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tristate "PWM driven LED Support"
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depends on LEDS_CLASS && HAVE_PWM
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help
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This option enables support for pwm driven LEDs
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comment "LED Triggers"
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config LEDS_TRIGGERS
+1
drivers/leds/Makefile
+1
drivers/leds/Makefile
+153
drivers/leds/leds-pwm.c
+153
drivers/leds/leds-pwm.c
···
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/*
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* linux/drivers/leds-pwm.c
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*
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* simple PWM based LED control
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*
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* Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
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*
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* based on leds-gpio.c by Raphael Assenat <raph@8d.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/fb.h>
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#include <linux/leds.h>
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#include <linux/err.h>
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#include <linux/pwm.h>
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#include <linux/leds_pwm.h>
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+
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struct led_pwm_data {
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struct led_classdev cdev;
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struct pwm_device *pwm;
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unsigned int active_low;
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unsigned int period;
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unsigned int max_brightness;
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};
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static void led_pwm_set(struct led_classdev *led_cdev,
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enum led_brightness brightness)
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{
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struct led_pwm_data *led_dat =
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container_of(led_cdev, struct led_pwm_data, cdev);
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unsigned int max = led_dat->max_brightness;
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unsigned int period = led_dat->period;
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+
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if (brightness == 0) {
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pwm_config(led_dat->pwm, 0, period);
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pwm_disable(led_dat->pwm);
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} else {
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pwm_config(led_dat->pwm, brightness * period / max, period);
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pwm_enable(led_dat->pwm);
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}
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}
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static int led_pwm_probe(struct platform_device *pdev)
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{
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struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
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struct led_pwm *cur_led;
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struct led_pwm_data *leds_data, *led_dat;
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int i, ret = 0;
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if (!pdata)
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return -EBUSY;
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leds_data = kzalloc(sizeof(struct led_pwm_data) * pdata->num_leds,
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GFP_KERNEL);
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if (!leds_data)
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return -ENOMEM;
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+
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for (i = 0; i < pdata->num_leds; i++) {
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cur_led = &pdata->leds[i];
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led_dat = &leds_data[i];
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led_dat->pwm = pwm_request(cur_led->pwm_id,
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cur_led->name);
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if (IS_ERR(led_dat->pwm)) {
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dev_err(&pdev->dev, "unable to request PWM %d\n",
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cur_led->pwm_id);
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goto err;
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}
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led_dat->cdev.name = cur_led->name;
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led_dat->cdev.default_trigger = cur_led->default_trigger;
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led_dat->active_low = cur_led->active_low;
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led_dat->max_brightness = cur_led->max_brightness;
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led_dat->period = cur_led->pwm_period_ns;
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led_dat->cdev.brightness_set = led_pwm_set;
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led_dat->cdev.brightness = LED_OFF;
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led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
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ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
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if (ret < 0) {
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pwm_free(led_dat->pwm);
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goto err;
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}
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}
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platform_set_drvdata(pdev, leds_data);
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return 0;
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err:
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if (i > 0) {
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for (i = i - 1; i >= 0; i--) {
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led_classdev_unregister(&leds_data[i].cdev);
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pwm_free(leds_data[i].pwm);
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}
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}
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kfree(leds_data);
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return ret;
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}
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static int __devexit led_pwm_remove(struct platform_device *pdev)
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{
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int i;
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struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
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struct led_pwm_data *leds_data;
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leds_data = platform_get_drvdata(pdev);
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for (i = 0; i < pdata->num_leds; i++) {
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led_classdev_unregister(&leds_data[i].cdev);
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pwm_free(leds_data[i].pwm);
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}
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kfree(leds_data);
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return 0;
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}
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static struct platform_driver led_pwm_driver = {
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.probe = led_pwm_probe,
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.remove = __devexit_p(led_pwm_remove),
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.driver = {
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.name = "leds_pwm",
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.owner = THIS_MODULE,
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},
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};
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static int __init led_pwm_init(void)
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{
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return platform_driver_register(&led_pwm_driver);
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}
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static void __exit led_pwm_exit(void)
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{
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platform_driver_unregister(&led_pwm_driver);
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}
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module_init(led_pwm_init);
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module_exit(led_pwm_exit);
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MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
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MODULE_DESCRIPTION("PWM LED driver for PXA");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:leds-pwm");
+21
include/linux/leds_pwm.h
+21
include/linux/leds_pwm.h
···
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/*
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* PWM LED driver data - see drivers/leds/leds-pwm.c
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*/
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#ifndef __LINUX_LEDS_PWM_H
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#define __LINUX_LEDS_PWM_H
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struct led_pwm {
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const char *name;
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const char *default_trigger;
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unsigned pwm_id;
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u8 active_low;
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unsigned max_brightness;
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unsigned pwm_period_ns;
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};
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struct led_pwm_platform_data {
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int num_leds;
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struct led_pwm *leds;
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};
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#endif