my_adc.c文件：
#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 <asm/io.h>#include <asm/irq.h>#include <asm/uaccess.h>#include <mach/regs-clock.h>#include <plat/regs-timer.h> #include <plat/regs-adc.h>#include <mach/regs-gpio.h>#include <linux/cdev.h>#include <linux/miscdevice.h>#include "s3c24xx-adc.h"#define DEVICE_NAME"myadc"static void __iomem *base_addr;typedef struct {wait_queue_head_t wait;int channel;int prescale;}ADC_DEV;DECLARE_MUTEX(ADC_LOCK);static int OwnADC = 0;static ADC_DEV adcdev;static volatile int ev_adc = 0;static int adc_data;#define ADCCON (*(volatile unsigned long *)(base_addr + S3C2410_ADCCON))//ADC control#define ADCTSC (*(volatile unsigned long *)(base_addr + S3C2410_ADCTSC))//ADC touch screen control#define ADCDLY (*(volatile unsigned long *)(base_addr + S3C2410_ADCDLY))//ADC start or Interval Delay#define ADCDAT0 (*(volatile unsigned long *)(base_addr + S3C2410_ADCDAT0))//ADC conversion data 0#define ADCDAT1 (*(volatile unsigned long *)(base_addr + S3C2410_ADCDAT1))//ADC conversion data 1#define ADCUPDN (*(volatile unsigned long *)(base_addr + 0x14))//Stylus Up/Down interrupt status#define PRESCALE_DIS (0 << 14)#define PRESCALE_EN (1 << 14)#define PRSCVL(x) ((x) << 6)#define ADC_INPUT(x) ((x) << 3)#define ADC_START (1 << 0)#define ADC_ENDCVT (1 << 15)#define START_ADC_AIN(ch, prescale) \do{ \ADCCON = PRESCALE_EN | PRSCVL(prescale) | ADC_INPUT((ch)) ; \ADCCON |= ADC_START; \}while(0)static irqreturn_t adcdone_int_handler(int irq, void *dev_id){if (OwnADC) {adc_data = ADCDAT0 & 0x3ff;ev_adc = 1;wake_up_interruptible(&adcdev.wait);}return IRQ_HANDLED;}static ssize_t s3c2410_adc_read(struct file *filp, char *buffer, size_t count, loff_t *ppos){char str[20];size_t len;if (down_trylock(&ADC_LOCK) == 0) {OwnADC = 1;START_ADC_AIN(adcdev.channel, adcdev.prescale);wait_event_interruptible(adcdev.wait, ev_adc);ev_adc = 0;OwnADC = 0;up(&ADC_LOCK);} len = sprintf(str, "%d", adc_data);if (count >= len) {int r = copy_to_user(buffer, str, len);return r ? r : len;} else {return -EINVAL;}}static int s3c2410_adc_open(struct inode *inode, struct file *filp){init_waitqueue_head(&(adcdev.wait));adcdev.channel=0;adcdev.prescale=0xff;printk ("adc opened\n");return 0;}static int s3c2410_adc_release(struct inode *inode, struct file *filp){printk ("adc closed\n");return 0;}static struct file_operations dev_fops = {owner:THIS_MODULE,open:s3c2410_adc_open,read:s3c2410_adc_read,release:s3c2410_adc_release,};static struct miscdevice misc = {.minor = MISC_DYNAMIC_MINOR,.name = DEVICE_NAME,.fops = &dev_fops,};static int __init dev_init(void){int ret;base_addr=ioremap(S3C2410_PA_ADC,0x20);if (base_addr == NULL) {printk(KERN_ERR "Failed to remap register block\n");return -ENOMEM;}/* normal ADC */ADCTSC = 0;ret = request_irq(IRQ_ADC, adcdone_int_handler, IRQF_SHARED, DEVICE_NAME, &adcdev);if (ret) {iounmap(base_addr);return ret;}ret = misc_register(&misc);printk (DEVICE_NAME"\tinitialized\n");return ret;}static void __exit dev_exit(void){free_irq(IRQ_ADC, &adcdev);iounmap(base_addr);misc_deregister(&misc);}module_init(dev_init);module_exit(dev_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("FriendlyARM Inc.");adc_test.c文件：
#include <stdio.h>#include <unistd.h>#include <stdlib.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/ioctl.h>#include <fcntl.h>#include <linux/fs.h>#include <errno.h>#include <string.h>int main(void){fprintf(stderr, "press Ctrl-C to stop\n");int fd = open("/dev/adc", 0);if (fd < 0) {perror("open ADC device:");return 1;}for(;;) {char buffer[30];int len = read(fd, buffer, sizeof buffer -1);if (len > 0) {buffer[len] = '\0';int value = -1;sscanf(buffer, "%d", &value);printf("ADC Value: %d\n", value);} else {perror("read ADC device:");return 1;}usleep(500* 1000);}close(fd);}
