移植環(huán)境

BootLoader：u-boot-1.1.6

kernel：linux-2.6.30.4

CPU：s3c2440

開發(fā)板：TQ2440

移植步驟

控制 LCD 背光的開關(guān)對于TQ2440 開發(fā)板來講，就是控制S3C2440 的 LCD 控制的LCD_PWREN 腳，根據(jù) S3C2440 的datasheet，可以知道在 LCDCON5 寄存器的 PWREN 位是控制 LCD 是否輸出的，當為 0 時 LCD 不輸出，此時 LCD_PWREN 腳為低，就會關(guān)閉 LCD 的背光；當為 1 時 LCD 輸出，此時 LCD_PWREN 腳為高，開啟 LCD 的背光。

1、編寫LCD背光驅(qū)動

對于 Linux-2.6.30.4 的內(nèi)核來講，需要重新制作LCD 背光驅(qū)動，命名為：le2440_backlight.c，內(nèi)容如下：

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#define DEVICE_NAME "backlight"

#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" initializedn");

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");

編寫Makefile如下：

#Makefile 

ifeq ($(KERNELRELEASE),) 

KERNELDIR ?= /home/linux/sky/ker/linux-2.6.30.4/ 

#KERNELDIR ?= /lib/modules/$(shell uname -r)/build 

PWD := $(shell pwd) 

modules: 

    $(MAKE) -C $(KERNELDIR) M=$(PWD)  

modules_install: 

    $(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install 

clean: 

    rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions Module* modules* 

.PHONY: modules modules_install clean 

else

obj-m := le2440_backlight.o 

endif 

然后make，生成 le2440_backlight.ko 文件，拷貝到NFS文件系統(tǒng)中

2、編寫應用程序控制LCD背光

編寫應用程序backlight.c，代碼如下：

#include

#include

#include

#include

#include

#include

int main(int argc, char **argv)

{

int turn;

int fd;

if ( argc == 1 )

{

fprintf(stderr, "nUsage: backlight on|off !nn");

exit(1);

}

fd = open("/dev/backlight", O_RDWR);

if (fd < 0) {

perror("open LCD device !");

exit(1);

}

if ( strcmp(argv[1], "on" ) == 0)

turn = 1;

else if ( strcmp(argv[1], "off" ) == 0)

turn = 0;

else

{

fprintf(stderr, "nUsage: backlight on|off !nn");

exit(1);

}

ioctl(fd, turn);

close(fd);

return 0;

}

編寫Makefile，如下：

CROSS=arm-linux-

all: backlight

backlight:backlight.c

$(CROSS)gcc -o backlight backlight.c

$(CROSS)strip backlight

clean:

@rm -vf backlight *.o *~

make生成可執(zhí)行文件backlight，拷貝到NFS文件系統(tǒng)中

3、測試LCD背光

可看到LCD屏亮滅