Linux_tq2440_背光灯驱动分析

背光灯的引脚是S3C2410_GPG4

可以这样定义

 

#define S3C2410_GPIO_BANKG   (32*6)

#define S3C2410_GPG4          S3C2410_GPIONO(S3C2410_GPIO_BANKG, 4)
#define S3C2410_GPG4_INP      (0x00 << 8)
#define S3C2410_GPG4_OUTP     (0x01 << 8)
#define S3C2410_GPG4_EINT12   (0x02 << 8)
#define S3C2400_GPG4_MMCCLK   (0x02 << 8)
#define S3C2400_GPG4_I2SSDI   (0x03 << 8)
#define S3C2410_GPG4_LCDPWREN (0x03 << 8)
#define S3C2443_GPG4_LCDPWRDN (0x03 << 8)

 

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);
   printk(DEVICE_NAME " Turn Off!\n");
   return 0;
  case 1:
   s3c2410_gpio_setpin(S3C2410_GPG4, 1);
   printk(DEVICE_NAME " Turn On!\n");
   return 0;
  default:
   return -EINVAL;
 }
}

程序调用的时候使用

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

ioctl(fd, 0);

close(fd);