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https://github.com/edk2-porting/linux-next.git
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8a66a57908
The code looks more nicer if we use: while (i--) instead: if (i > 0) for (i = i - 1; i >= 0; i--) Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Bryan Wu <cooloney@gmail.com>
139 lines
3.3 KiB
C
139 lines
3.3 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/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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#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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};
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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_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 int period = led_dat->period;
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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 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 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_priv *priv;
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int i, ret = 0;
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if (!pdata)
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return -EBUSY;
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priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(pdata->num_leds),
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GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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for (i = 0; i < pdata->num_leds; i++) {
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struct led_pwm *cur_led = &pdata->leds[i];
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struct led_pwm_data *led_dat = &priv->leds[i];
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led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
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if (IS_ERR(led_dat->pwm)) {
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ret = PTR_ERR(led_dat->pwm);
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dev_err(&pdev->dev, "unable to request PWM for %s\n",
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cur_led->name);
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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->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.max_brightness = cur_led->max_brightness;
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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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goto err;
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}
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priv->num_leds = pdata->num_leds;
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platform_set_drvdata(pdev, priv);
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return 0;
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err:
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while (i--)
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led_classdev_unregister(&priv->leds[i].cdev);
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return ret;
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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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int i;
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for (i = 0; i < priv->num_leds; i++)
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led_classdev_unregister(&priv->leds[i].cdev);
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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 = 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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module_platform_driver(led_pwm_driver);
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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");
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