linux设备驱动 ADC测试

XC2440开发板提供了adc的测试程序，内核配置时已经加入了adc的驱动，下面测试一下看看效果

1：通过ftp工具将 adc_test执行文件传到开发板上 var/ftp/pub目录下

2：chmod a+x adc_test 改变文件权限

3：./adc_test 1    说明：./adc_test 是运行程序  1是运行程序的参数，这里表示对adc通道1操作

 

/**************************************************************************
  XC2440 hwmon-adc driver test
  device node is "/sys/class/hwmon/hwmon0/device/adcN_raw"
  www.xcembed.com 2011.05
***************************************************************************/
/***************************************************************************
 * *
 * This program is free software; you can redistribute it and/or modify *
 * it under the terms of the GNU General Public License as published by *
 * the Free Software Foundation; either version 2 of the License, or *
 * (at your option) any later version. *
 * *
 ***************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/fcntl.h>

int main(int argc, char *argv[])
{
    int fd = -1, ret;
    int adc_ch, value;
    char buffer[5];
    char dev_name[50];

    if ( argc < 2 )
    {
        printf("usage adc_test chanel(0~7)\n");
        exit(1);
    }
    else
    {
        adc_ch = atoi(argv[1]);
    }

    if ( (adc_ch >= 0) && (adc_ch <= 7) )
    {
        sprintf(dev_name, "/sys/class/hwmon/hwmon0/device/adc%d_raw\0", adc_ch);
        //printf("dev name %s\n", dev_name);

        if ((fd = open(dev_name, O_RDONLY)) < 0)
        {
            perror("open error");
            exit(1);
        }
    }
    else
    {
        printf("adc_ch is (0~7)\n");
        exit(1);
    }

    ret = read(fd, buffer, 4);
    if (ret < 0)
    {
        perror("read error");
        exit(1);
    }

    value = atoi(buffer);
    printf("ADC %d current value is %d\n", adc_ch, value);

    close(fd);
    return 0;
}

 

makefile内容：

CROSS=arm-linux-

all: adc_test

adc_test:adc_test.c
 $(CROSS)gcc -o adc_test adc_test.c
 $(CROSS)strip adc_test
clean:
 @rm -f adc_test *.o *~