TQ2440背光控制

控制LCD背光就是控制S3C2440的LCD控制的LCD_PWREN脚LCDCON5寄存器PWREN位控制LCD是否输出。

对Linux_2.6.30.4内核进行移植。新建一个backlight.c文件放到“drivers/video”目录下。内容如下：

/*************************************

NAME:EmbedSky_backlight.c
COPYRIGHT:www.embedsky.net

*************************************/


#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/init.h>
#include <linux/serio.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/miscdevice.h>


#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <mach/regs-clock.h>
#include <plat/regs-timer.h>
 
#include <mach/regs-gpio.h>
#include <mach/fb.h>
#include <linux/cdev.h>


#define DEVICE_NAME "bkl"


#define S3C2440_LCD_BASE 0x59000000
#define S3C2440_LCDCON1 (S3C2440_LCD_BASE + 0x00)
volatile int *lcdcon1 = NULL;




static int tq2440_backlight_ioctl(
struct inode *inode, 
struct file *file, 
unsigned int cmd, 
unsigned long arg)
{
switch(cmd)
{
case 0:
s3c2410_gpio_setpin(S3C2410_GPG4, 0);
//*lcdcon1 = *lcdcon1 & (~(0x1<<0));
printk("backlight Turn Off!\n");
return 0;
case 1:
s3c2410_gpio_setpin(S3C2410_GPG4, 1);
//*lcdcon1 |= (0x1<<0);
printk("backlight Turn On!\n");
return 0;
default:
return -EINVAL;
}
}


static struct file_operations dev_fops = {
.owner = THIS_MODULE,
.ioctl = tq2440_backlight_ioctl
};


static struct miscdevice misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = DEVICE_NAME,
.fops = &dev_fops,
};


static int __init dev_init(void)
{
int ret;


lcdcon1 = (int *)ioremap(S3C2440_LCDCON1, 4);
ret = misc_register(&misc);


printk (DEVICE_NAME" initialized\n");


s3c2410_gpio_cfgpin(S3C2410_GPG4, S3C2410_GPG4_OUTP);
return ret;
}




static void __exit dev_exit(void)
{
misc_deregister(&misc);
}


module_init(dev_init);
module_exit(dev_exit);


MODULE_LICENSE("GPL");
MODULE_AUTHOR("www.embedsky.net");
MODULE_DESCRIPTION("Backlight control for EmbedSky SKY2440/TQ2440 Board");

然后修改“drivers/video/Kconfig”文件，在1984行添加如下内容：

config FB_S3C2410_DEBUG
bool "S3C2410 lcd debug messages"
depends on FB_S3C24X0
help
 Turn on debugging messages. Note that you can set/unset at run time
 through sysfs


config TQ2440_BACKLIGHT
bool "EmbedSky SKY2440/TQ2440 Board Backlight control"
depends on FB_S3C24X0
help
 Backlight control for EmbedSky SKY2440/TQ2440 Board.

再修改“drivers/video/Makefile”文件，在115行添加：

obj-$(CONFIG_TQ2440_BACKLIGHT)+= backlight.o

修改完成以后配置内核镜像

配置完以后编译出内核镜像。

编写LCD背光控制程序和编辑Makefile文件。最后测试LCD背光开关。