![Johan Hovold](/assets/img/avatar_default.png)
Use devm_gpio_request_one rather than requesting and setting direction in two calls. Signed-off-by: Johan Hovold <jhovold@gmail.com> Cc: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
224 lines
5.6 KiB
C
224 lines
5.6 KiB
C
/*
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* Copyright (C) 2008 Atmel Corporation
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*
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* Backlight driver using Atmel PWM peripheral.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/fb.h>
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#include <linux/gpio.h>
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#include <linux/backlight.h>
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#include <linux/atmel_pwm.h>
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#include <linux/atmel-pwm-bl.h>
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#include <linux/slab.h>
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struct atmel_pwm_bl {
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const struct atmel_pwm_bl_platform_data *pdata;
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struct backlight_device *bldev;
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struct platform_device *pdev;
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struct pwm_channel pwmc;
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int gpio_on;
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};
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static void atmel_pwm_bl_set_gpio_on(struct atmel_pwm_bl *pwmbl, int on)
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{
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if (!gpio_is_valid(pwmbl->gpio_on))
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return;
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gpio_set_value(pwmbl->gpio_on, on ^ pwmbl->pdata->on_active_low);
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}
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static int atmel_pwm_bl_set_intensity(struct backlight_device *bd)
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{
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struct atmel_pwm_bl *pwmbl = bl_get_data(bd);
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int intensity = bd->props.brightness;
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int pwm_duty;
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if (bd->props.power != FB_BLANK_UNBLANK)
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intensity = 0;
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if (bd->props.fb_blank != FB_BLANK_UNBLANK)
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intensity = 0;
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if (pwmbl->pdata->pwm_active_low)
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pwm_duty = pwmbl->pdata->pwm_duty_min + intensity;
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else
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pwm_duty = pwmbl->pdata->pwm_duty_max - intensity;
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if (pwm_duty > pwmbl->pdata->pwm_duty_max)
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pwm_duty = pwmbl->pdata->pwm_duty_max;
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if (pwm_duty < pwmbl->pdata->pwm_duty_min)
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pwm_duty = pwmbl->pdata->pwm_duty_min;
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if (!intensity) {
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atmel_pwm_bl_set_gpio_on(pwmbl, 0);
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pwm_channel_writel(&pwmbl->pwmc, PWM_CUPD, pwm_duty);
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pwm_channel_disable(&pwmbl->pwmc);
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} else {
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pwm_channel_enable(&pwmbl->pwmc);
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pwm_channel_writel(&pwmbl->pwmc, PWM_CUPD, pwm_duty);
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atmel_pwm_bl_set_gpio_on(pwmbl, 1);
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}
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return 0;
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}
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static int atmel_pwm_bl_get_intensity(struct backlight_device *bd)
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{
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struct atmel_pwm_bl *pwmbl = bl_get_data(bd);
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u32 cdty;
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u32 intensity;
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cdty = pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY);
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if (pwmbl->pdata->pwm_active_low)
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intensity = cdty - pwmbl->pdata->pwm_duty_min;
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else
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intensity = pwmbl->pdata->pwm_duty_max - cdty;
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return intensity & 0xffff;
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}
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static int atmel_pwm_bl_init_pwm(struct atmel_pwm_bl *pwmbl)
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{
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unsigned long pwm_rate = pwmbl->pwmc.mck;
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unsigned long prescale = DIV_ROUND_UP(pwm_rate,
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(pwmbl->pdata->pwm_frequency *
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pwmbl->pdata->pwm_compare_max)) - 1;
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/*
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* Prescale must be power of two and maximum 0xf in size because of
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* hardware limit. PWM speed will be:
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* PWM module clock speed / (2 ^ prescale).
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*/
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prescale = fls(prescale);
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if (prescale > 0xf)
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prescale = 0xf;
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pwm_channel_writel(&pwmbl->pwmc, PWM_CMR, prescale);
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pwm_channel_writel(&pwmbl->pwmc, PWM_CDTY,
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pwmbl->pdata->pwm_duty_min +
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pwmbl->bldev->props.brightness);
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pwm_channel_writel(&pwmbl->pwmc, PWM_CPRD,
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pwmbl->pdata->pwm_compare_max);
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dev_info(&pwmbl->pdev->dev, "Atmel PWM backlight driver (%lu Hz)\n",
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pwmbl->pwmc.mck / pwmbl->pdata->pwm_compare_max /
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(1 << prescale));
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return pwm_channel_enable(&pwmbl->pwmc);
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}
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static const struct backlight_ops atmel_pwm_bl_ops = {
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.get_brightness = atmel_pwm_bl_get_intensity,
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.update_status = atmel_pwm_bl_set_intensity,
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};
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static int atmel_pwm_bl_probe(struct platform_device *pdev)
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{
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struct backlight_properties props;
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const struct atmel_pwm_bl_platform_data *pdata;
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struct backlight_device *bldev;
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struct atmel_pwm_bl *pwmbl;
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unsigned long flags;
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int retval;
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pdata = dev_get_platdata(&pdev->dev);
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if (!pdata)
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return -ENODEV;
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if (pdata->pwm_compare_max < pdata->pwm_duty_max ||
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pdata->pwm_duty_min > pdata->pwm_duty_max ||
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pdata->pwm_frequency == 0)
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return -EINVAL;
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pwmbl = devm_kzalloc(&pdev->dev, sizeof(struct atmel_pwm_bl),
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GFP_KERNEL);
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if (!pwmbl)
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return -ENOMEM;
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pwmbl->pdev = pdev;
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pwmbl->pdata = pdata;
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pwmbl->gpio_on = pdata->gpio_on;
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retval = pwm_channel_alloc(pdata->pwm_channel, &pwmbl->pwmc);
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if (retval)
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return retval;
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if (gpio_is_valid(pwmbl->gpio_on)) {
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/* Turn display off by default. */
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if (pdata->on_active_low)
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flags = GPIOF_OUT_INIT_HIGH;
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else
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flags = GPIOF_OUT_INIT_LOW;
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retval = devm_gpio_request_one(&pdev->dev, pwmbl->gpio_on,
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flags, "gpio_atmel_pwm_bl");
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if (retval)
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goto err_free_pwm;
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}
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memset(&props, 0, sizeof(struct backlight_properties));
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props.type = BACKLIGHT_RAW;
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props.max_brightness = pdata->pwm_duty_max - pdata->pwm_duty_min;
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bldev = devm_backlight_device_register(&pdev->dev, "atmel-pwm-bl",
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&pdev->dev, pwmbl, &atmel_pwm_bl_ops,
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&props);
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if (IS_ERR(bldev)) {
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retval = PTR_ERR(bldev);
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goto err_free_pwm;
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}
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pwmbl->bldev = bldev;
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platform_set_drvdata(pdev, pwmbl);
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/* Power up the backlight by default at middle intesity. */
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bldev->props.power = FB_BLANK_UNBLANK;
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bldev->props.brightness = bldev->props.max_brightness / 2;
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retval = atmel_pwm_bl_init_pwm(pwmbl);
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if (retval)
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goto err_free_pwm;
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atmel_pwm_bl_set_intensity(bldev);
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return 0;
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err_free_pwm:
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pwm_channel_free(&pwmbl->pwmc);
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return retval;
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}
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static int atmel_pwm_bl_remove(struct platform_device *pdev)
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{
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struct atmel_pwm_bl *pwmbl = platform_get_drvdata(pdev);
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atmel_pwm_bl_set_gpio_on(pwmbl, 0);
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pwm_channel_disable(&pwmbl->pwmc);
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pwm_channel_free(&pwmbl->pwmc);
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return 0;
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}
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static struct platform_driver atmel_pwm_bl_driver = {
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.driver = {
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.name = "atmel-pwm-bl",
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},
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/* REVISIT add suspend() and resume() */
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.probe = atmel_pwm_bl_probe,
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.remove = atmel_pwm_bl_remove,
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};
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module_platform_driver(atmel_pwm_bl_driver);
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MODULE_AUTHOR("Hans-Christian egtvedt <hans-christian.egtvedt@atmel.com>");
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MODULE_DESCRIPTION("Atmel PWM backlight driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:atmel-pwm-bl");
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