mini2440如何 实现AD采集

因为mini2440的AD的AIN0是连在AIN0，和可调电阻相连的，我现在需要用它来进行AD采集。不是裸机，而是跑操作系统Linux，求解，怎么解决啊，如何修改哪个源代码用来采集电压。。。。

1.把AIN0上电路的可调电阻去掉

2.修改驱动，用AIN1或AIN2来读取

PS：吐槽一下为啥驱动里面不做通道选择，不难吧……
static ssize_t s3c2410_adc_write(struct file *filp, const char *buffer, size_t count, loff_t *ppos)
{
        unsigned long data;

        /*
        if(count!=sizeof(data)) {  
                printk(KERN_INFO"the size of input data must be %d\n", sizeof(data));
                return 0;
        }
        // */

        copy_from_user(&data, buffer, count);
        adcdev.channel = ADC_WRITE_GETCH(data);
        adcdev.prescale = ADC_WRITE_GETPRE(data);

        //DPRINTK("set adc channel=%d, prescale=0x%x\n", adcdev.channel, adcdev.prescale);
        printk("set adc channel=%d, prescale=0x%x\n", adcdev.channel, adcdev.prescale);
        return count;
}
打开adc设备的时候记得用O_RDWR，可以通道选择，分频设置

PS2：DPRINTK宏定义有问题，开了DEBUG之后不能编译通过？

测试代码：
        int fd = open("/dev/adc", O_RDWR);
        if (fd < 0) {
                perror("open ADC device:");
                return 1;
        }

        printf("Please select which chanel(0--2): \n");
        scanf("%d", &chan);
        printf("Please select prescale:\n");
        scanf("%d", &pres);
        setdata = chan<<16|pres;
        result = write(fd, &setdata, sizeof(setdata));
        if (!result) {
                printf("wrong when writing!\n");
        }