OK6410之ADC驱动程序 混杂设备

mini6410 实现 linux adc驱动详解--muge0913版

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/serio.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/sched.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>

#include <plat/regs-adc.h>
#include <mach/map.h>

static void __iomem * base_addr;
static struct clk *adc_clock;

/*#define ADCCON_BASE      (0x7E00B000)
#define ADCCON           (*(volatile unsigned *)(ADCCON_BASE+0x00))    // ADC control
#define ADCTSC           (*(volatile unsigned *)(ADCCON_BASE+0x04))    // ADC touch screen control
#define ADCDLY           (*(volatile unsigned *)(ADCCON_BASE+0x08))    // ADC start or Interval Delay
#define ADCDAT0          (*(volatile unsigned *)(ADCCON_BASE+0x0C))   // ADC conversion data 0
#define ADCDAT1          (*(volatile unsigned *)(ADCCON_BASE+0x10))   // ADC conversion data 1
#define ADCUPDN          (*(volatile unsigned *)(ADCCON_BASE+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)   */

/*ADC寄存器地址*/
#define __ADCREG(name)  (*(volatile unsigned long *)(base_addr + name))
#define ADCCON          __ADCREG(S3C_ADCCON)    // ADC control
#define ADCTSC          __ADCREG(S3C_ADCTSC)    // ADC touch screen control
#define ADCDLY          __ADCREG(S3C_ADCDLY)    // ADC start or Interval Delay
#define ADCDAT0         __ADCREG(S3C_ADCDAT0)   // ADC conversion data 0
#define ADCDAT1         __ADCREG(S3C_ADCDAT1)   // ADC conversion data 1
#define ADCUPDN         __ADCREG(S3C_ADCUPDN)   // Stylus Up/Down interrupt status

/*根据s3c6410的文档，设置相应的ADC控制器位*/
#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 DEVICE_NAME  "adc_dev"

static int adc_init()
{
printk("<0>adc_init sucessed!\n");
unsigned int preScaler = 0XFF;
printk("<0>111111111!\n");
ADCCON  = (1<<14)|(preScaler<<6)|(0<<3)|(0<<2);
ADCCON |= ADC_START;
printk("<0>2222222222!\n");
return 0;

}
static int adc_open(struct inode *inode ,struct file *filp)
{
printk("adc_open!\n");
adc_init();
return 0;
}
static int adc_release(struct inode *inode,struct file *filp)
{
return 0;
}
static ssize_t adc_read(struct file *filp,char __user *buff,size_t size,loff_t *ppos)
{
printk("<0>adc_read!\n");
int ret=0;
ADCCON |= ADC_START;
while(ADCCON & 0x01);//check if Enable_start is low
while(!(ADCCON &0x8000));/*检查转换是否结束*/
ret = ADCDAT0 & 0x3ff;    //重点，与参考的不同，我觉得这样才是正确的
copy_to_user(buff,(char *)&ret,sizeof(ret));

return sizeof(ret);
}

static struct file_operations dev_fops =
{
.owner = THIS_MODULE,
.open = adc_open,
.release = adc_release,
.read = adc_read,
};

static struct miscdevice misc =
{
.minor = MISC_DYNAMIC_MINOR,
.name = DEVICE_NAME,
.fops = &dev_fops,
};

static int __init dev_init()
{
int ret;

base_addr =ioremap(0x7E00B000,0X20);//地址映射
printk("<0>ioremap sucessed!\n");
if(base_addr == NULL)
{
printk(KERN_ERR"failed to remap\n");
return -ENOMEM;
}

adc_clock = clk_get(NULL,"adc");//激活adc时钟模块
printk("<0>clk_get sucessed!\n");
if(!adc_clock)
{
printk(KERN_ERR"failed to get adc clock\n");
return -ENOENT;
}
clk_enable(adc_clock);

ret = misc_register(&misc);//混杂设备注册
printk("dev_init return ret:%d\n",ret);
return ret;
}
static void __exit dev_exit()
{
iounmap(base_addr);//取消映射

if(adc_clock)//disable adc clock取消adc时钟
{
clk_disable(adc_clock);
clk_put(adc_clock);
adc_clock =NULL;
}
misc_deregister(&misc);//注销混杂设备

}
module_init(dev_init);
module_exit(dev_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("MUGE0913");

#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>

int main()
{
int fp,adc_data,i;
int ret;
fp = open("/dev/adc_dev",O_RDWR);
if(fp<0)
printf("open failed!\n");
printf("open sucessed!\n");

for(i=0;i<100;i++)
{
ret = read(fp,&adc_data,sizeof(adc_data));
printf("read sucessed!\n");
if(ret<0)
{
printf("read ADC failed!\n");
return -1;
}
else
printf("Read ADC value is: %d\n",adc_data);
sleep(1);
}
close(fp);
return 0;
}