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![Boris Brezillon](/assets/img/avatar_default.png)
The PWM framework has clarified the concept of reference PWM config (the platform dependent config retrieved from the DT or the PWM lookup table) and real PWM state. Use pwm_get_args() when the PWM user wants to retrieve this reference config and not the current state. This is part of the rework allowing the PWM framework to support hardware readout and expose real PWM state even when the PWM has just been requested (before the user calls pwm_config/enable/disable()). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
243 lines
5.4 KiB
C
243 lines
5.4 KiB
C
/*
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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/platform_device.h>
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#include <linux/of_platform.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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#include <linux/slab.h>
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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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int duty;
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bool can_sleep;
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};
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struct led_pwm_priv {
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int num_leds;
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struct led_pwm_data leds[0];
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};
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static void __led_pwm_set(struct led_pwm_data *led_dat)
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{
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int new_duty = led_dat->duty;
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pwm_config(led_dat->pwm, new_duty, led_dat->period);
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if (new_duty == 0)
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pwm_disable(led_dat->pwm);
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else
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pwm_enable(led_dat->pwm);
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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->cdev.max_brightness;
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unsigned long long duty = led_dat->period;
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duty *= brightness;
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do_div(duty, max);
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if (led_dat->active_low)
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duty = led_dat->period - duty;
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led_dat->duty = duty;
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__led_pwm_set(led_dat);
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}
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static int led_pwm_set_blocking(struct led_classdev *led_cdev,
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enum led_brightness brightness)
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{
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led_pwm_set(led_cdev, brightness);
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return 0;
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}
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static inline size_t sizeof_pwm_leds_priv(int num_leds)
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{
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return sizeof(struct led_pwm_priv) +
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(sizeof(struct led_pwm_data) * num_leds);
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}
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static void led_pwm_cleanup(struct led_pwm_priv *priv)
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{
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while (priv->num_leds--)
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led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
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}
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static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
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struct led_pwm *led, struct device_node *child)
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{
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struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
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struct pwm_args pargs;
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int ret;
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led_data->active_low = led->active_low;
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led_data->cdev.name = led->name;
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led_data->cdev.default_trigger = led->default_trigger;
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led_data->cdev.brightness = LED_OFF;
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led_data->cdev.max_brightness = led->max_brightness;
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led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
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if (child)
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led_data->pwm = devm_of_pwm_get(dev, child, NULL);
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else
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led_data->pwm = devm_pwm_get(dev, led->name);
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if (IS_ERR(led_data->pwm)) {
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ret = PTR_ERR(led_data->pwm);
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dev_err(dev, "unable to request PWM for %s: %d\n",
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led->name, ret);
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return ret;
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}
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led_data->can_sleep = pwm_can_sleep(led_data->pwm);
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if (!led_data->can_sleep)
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led_data->cdev.brightness_set = led_pwm_set;
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else
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led_data->cdev.brightness_set_blocking = led_pwm_set_blocking;
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/*
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* FIXME: pwm_apply_args() should be removed when switching to the
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* atomic PWM API.
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*/
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pwm_apply_args(led_data->pwm);
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pwm_get_args(led_data->pwm, &pargs);
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led_data->period = pargs.period;
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if (!led_data->period && (led->pwm_period_ns > 0))
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led_data->period = led->pwm_period_ns;
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ret = led_classdev_register(dev, &led_data->cdev);
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if (ret == 0) {
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priv->num_leds++;
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led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
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} else {
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dev_err(dev, "failed to register PWM led for %s: %d\n",
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led->name, ret);
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}
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return ret;
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}
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static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
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{
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struct device_node *child;
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struct led_pwm led;
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int ret = 0;
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memset(&led, 0, sizeof(led));
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for_each_child_of_node(dev->of_node, child) {
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led.name = of_get_property(child, "label", NULL) ? :
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child->name;
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led.default_trigger = of_get_property(child,
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"linux,default-trigger", NULL);
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led.active_low = of_property_read_bool(child, "active-low");
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of_property_read_u32(child, "max-brightness",
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&led.max_brightness);
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ret = led_pwm_add(dev, priv, &led, child);
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if (ret) {
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of_node_put(child);
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break;
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}
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}
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return ret;
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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 = dev_get_platdata(&pdev->dev);
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struct led_pwm_priv *priv;
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int count, i;
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int ret = 0;
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if (pdata)
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count = pdata->num_leds;
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else
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count = of_get_child_count(pdev->dev.of_node);
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if (!count)
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return -EINVAL;
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priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
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GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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if (pdata) {
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for (i = 0; i < count; i++) {
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ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
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NULL);
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if (ret)
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break;
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}
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} else {
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ret = led_pwm_create_of(&pdev->dev, priv);
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}
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if (ret) {
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led_pwm_cleanup(priv);
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return ret;
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}
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platform_set_drvdata(pdev, priv);
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return 0;
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}
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static int led_pwm_remove(struct platform_device *pdev)
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{
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struct led_pwm_priv *priv = platform_get_drvdata(pdev);
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led_pwm_cleanup(priv);
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return 0;
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}
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static const struct of_device_id of_pwm_leds_match[] = {
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{ .compatible = "pwm-leds", },
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{},
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};
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MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
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static struct platform_driver led_pwm_driver = {
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.probe = led_pwm_probe,
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.remove = led_pwm_remove,
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.driver = {
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.name = "leds_pwm",
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.of_match_table = of_pwm_leds_match,
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},
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};
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module_platform_driver(led_pwm_driver);
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MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
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MODULE_DESCRIPTION("generic PWM LED driver");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:leds-pwm");
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