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Commit f00207b2 authored by Banajit Goswami's avatar Banajit Goswami Committed by Kukjin Kim
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ARM: SAMSUNG: Create a common infrastructure for PWM backlight support 



This patch creates a common structure for LCD backlight
using PWM timer to be used by various Samsung boards.

Signed-off-by: default avatarBanajit Goswami <banajit.g@samsung.com>
Signed-off-by: default avatarKukjin Kim <kgene.kim@samsung.com>
parent 0665ccc4

arch/arm/plat-samsung/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -280,6 +280,12 @@ config SAMSUNG_DEV_PWM 
	help

	  Compile in platform device definition for PWM Timer



config SAMSUNG_DEV_BACKLIGHT

	bool

	depends on SAMSUNG_DEV_PWM

	help

	  Compile in platform device definition LCD backlight with PWM Timer



config S3C24XX_PWM

	bool "PWM device support"

	select HAVE_PWM

arch/arm/plat-samsung/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ obj-$(CONFIG_SAMSUNG_DEV_IDE) += dev-ide.o 
obj-$(CONFIG_SAMSUNG_DEV_TS)	+= dev-ts.o

obj-$(CONFIG_SAMSUNG_DEV_KEYPAD)	+= dev-keypad.o

obj-$(CONFIG_SAMSUNG_DEV_PWM)	+= dev-pwm.o

obj-$(CONFIG_SAMSUNG_DEV_BACKLIGHT)	+= dev-backlight.o



# DMA support

arch/arm/plat-samsung/dev-backlight.c

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Original line number Diff line number Diff line 
/* linux/arch/arm/plat-samsung/dev-backlight.c

 *

 * Copyright (c) 2011 Samsung Electronics Co., Ltd.

 *              http://www.samsung.com

 *

 * Common infrastructure for PWM Backlight for Samsung boards

 *

 * 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/gpio.h>

#include <linux/platform_device.h>

#include <linux/io.h>

#include <linux/pwm_backlight.h>



#include <plat/devs.h>

#include <plat/gpio-cfg.h>

#include <plat/backlight.h>



static int samsung_bl_init(struct device *dev)

{

	int ret = 0;

	struct platform_device *timer_dev =

			container_of(dev->parent, struct platform_device, dev);

	struct samsung_bl_gpio_info *bl_gpio_info =

			timer_dev->dev.platform_data;



	ret = gpio_request(bl_gpio_info->no, "Backlight");

	if (ret) {

		printk(KERN_ERR "failed to request GPIO for LCD Backlight\n");

		return ret;

	}



	/* Configure GPIO pin with specific GPIO function for PWM timer */

	s3c_gpio_cfgpin(bl_gpio_info->no, bl_gpio_info->func);



	return 0;

}



static void samsung_bl_exit(struct device *dev)

{

	struct platform_device *timer_dev =

			container_of(dev->parent, struct platform_device, dev);

	struct samsung_bl_gpio_info *bl_gpio_info =

			timer_dev->dev.platform_data;



	s3c_gpio_cfgpin(bl_gpio_info->no, S3C_GPIO_OUTPUT);

	gpio_free(bl_gpio_info->no);

}



/* Initialize few important fields of platform_pwm_backlight_data

 * structure with default values. These fields can be overridden by

 * board-specific values sent from machine file.

 * For ease of operation, these fields are initialized with values

 * used by most samsung boards.

 * Users has the option of sending info about other parameters

 * for their specific boards

 */



static struct platform_pwm_backlight_data samsung_dfl_bl_data __initdata = {

	.max_brightness = 255,

	.dft_brightness = 255,

	.pwm_period_ns  = 78770,

	.init           = samsung_bl_init,

	.exit           = samsung_bl_exit,

};



static struct platform_device samsung_dfl_bl_device __initdata = {

	.name		= "pwm-backlight",

};



/* samsung_bl_set - Set board specific data (if any) provided by user for

 * PWM Backlight control and register specific PWM and backlight device.

 * @gpio_info:	structure containing GPIO info for PWM timer

 * @bl_data:	structure containing Backlight control data

 */

void samsung_bl_set(struct samsung_bl_gpio_info *gpio_info,

	struct platform_pwm_backlight_data *bl_data)

{

	int ret = 0;

	struct platform_device *samsung_bl_device;

	struct platform_pwm_backlight_data *samsung_bl_data;



	samsung_bl_device = kmemdup(&samsung_dfl_bl_device,

			sizeof(struct platform_device), GFP_KERNEL);

	if (!samsung_bl_device) {

		printk(KERN_ERR "%s: no memory for platform dev\n", __func__);

		return;

	}



	samsung_bl_data = s3c_set_platdata(&samsung_dfl_bl_data,

		sizeof(struct platform_pwm_backlight_data), samsung_bl_device);

	if (!samsung_bl_data) {

		printk(KERN_ERR "%s: no memory for platform dev\n", __func__);

		goto err_data;

	}



	/* Copy board specific data provided by user */

	samsung_bl_data->pwm_id = bl_data->pwm_id;

	samsung_bl_device->dev.parent =

			&s3c_device_timer[samsung_bl_data->pwm_id].dev;



	if (bl_data->max_brightness)

		samsung_bl_data->max_brightness = bl_data->max_brightness;

	if (bl_data->dft_brightness)

		samsung_bl_data->dft_brightness = bl_data->dft_brightness;

	if (bl_data->lth_brightness)

		samsung_bl_data->lth_brightness = bl_data->lth_brightness;

	if (bl_data->pwm_period_ns)

		samsung_bl_data->pwm_period_ns = bl_data->pwm_period_ns;

	if (bl_data->init)

		samsung_bl_data->init = bl_data->init;

	if (bl_data->notify)

		samsung_bl_data->notify = bl_data->notify;

	if (bl_data->exit)

		samsung_bl_data->exit = bl_data->exit;

	if (bl_data->check_fb)

		samsung_bl_data->check_fb = bl_data->check_fb;



	/* Keep the GPIO info for future use */

	s3c_device_timer[samsung_bl_data->pwm_id].dev.platform_data = gpio_info;



	/* Register the specific PWM timer dev for Backlight control */

	ret = platform_device_register(

			&s3c_device_timer[samsung_bl_data->pwm_id]);

	if (ret) {

		printk(KERN_ERR "failed to register pwm timer for backlight: %d\n", ret);

		goto err_plat_reg1;

	}



	/* Register the Backlight dev */

	ret = platform_device_register(samsung_bl_device);

	if (ret) {

		printk(KERN_ERR "failed to register backlight device: %d\n", ret);

		goto err_plat_reg2;

	}



	return;



err_plat_reg2:

	platform_device_unregister(&s3c_device_timer[samsung_bl_data->pwm_id]);

err_plat_reg1:

	kfree(samsung_bl_data);

err_data:

	kfree(samsung_bl_device);

	return;

}

arch/arm/plat-samsung/include/plat/backlight.h

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/* linux/arch/arm/plat-samsung/include/plat/backlight.h

 *

 * Copyright (c) 2011 Samsung Electronics Co., Ltd.

 *              http://www.samsung.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.

 */



#ifndef __ASM_PLAT_BACKLIGHT_H

#define __ASM_PLAT_BACKLIGHT_H __FILE__



/* samsung_bl_gpio_info - GPIO info for PWM Backlight control

 * @no:		GPIO number for PWM timer out

 * @func:	Special function of GPIO line for PWM timer

 */

struct samsung_bl_gpio_info {

	int no;

	int func;

};



extern void samsung_bl_set(struct samsung_bl_gpio_info *gpio_info,

	struct platform_pwm_backlight_data *bl_data);



#endif /* __ASM_PLAT_BACKLIGHT_H */