adc.c

MC2410A的ADC驱动

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/miscdevice.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/wait.h>
#include <linux/device.h>
#include <asm/irq.h>
#include <linux/types.h>
#include <linux/cdev.h>
#include <linux/errno.h>
#include <asm/arch/map.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/arch/regs-gpio.h>
#include <asm/arch-s3c2410/map.h>
#include <asm/arch-s3c2410/regs-adc.h>
#include <asm/arch-s3c2410/regs-clock.h>
#include "adc.h"

#define DEVICE_NAME "adc"
//#define ADC_MAJOR 240
#define ADCCON	(S3C24XX_VA_ADC + 0x00) //S3C2410_ADCCON
#define ADCTSC	(S3C24XX_VA_ADC + 0x04) //S3C2410_ADCTSC
#define ADCDAT0	(S3C24XX_VA_ADC + 0x0C) //S3C2410_ADCDAT0
#define CLKCON	(S3C24XX_VA_CLKPWR + 0x0C) //S3C2410_CLKCON
static int adc_major=254;

MODULE_AUTHOR("akae_group");
MODULE_DESCRIPTION("adc module");
MODULE_LICENSE("GPL");

static ssize_t adc_read(struct file *filp,char __user *buf,
						size_t count,loff_t *f_pos)
{
	int data=0;
	unsigned int tmp;
//	printk("1.........\n");

	tmp=readl(ADCCON) | 0x01;
	writel(tmp,ADCCON);
//	printk("2..........\n");

	do {
		tmp=readl(ADCCON);
	}while(((unsigned short)tmp) & 0x01);
//	printk("3..........\n");
	
	do {
		tmp=readl(ADCCON);
	}while(!(((unsigned short)tmp) & 0x8000));
	
//	printk("4.........\n");
	data=readl(ADCDAT0) & 0x3ff;

//	printk("5..........\n");
//	printk("data=%d\n",data);

	if(copy_to_user(buf,&data,sizeof(data)))
		return -EFAULT;
	return (sizeof(int));
}

static int adc_initial(void)
{
	unsigned int tmp;

	writel((readl(CLKCON) | S3C2410_CLKCON_ADC),CLKCON);
	
	tmp=readl(ADCTSC);
//	tmp &= (~S3C2410_ADCTSC_AUTO_PST) | S3C2410_ADCTSC_XY_PST(S3C2410_NOP_MODE);
	tmp &= (~S3C2410_ADCTSC_AUTO_PST);
	writel(tmp,ADCTSC);

	tmp=readl(ADCCON);
	tmp= S3C2410_ADCCON_PRSCEN | PRSCVL(49) | ADC_INPUT(0);
	writel(tmp,ADCCON);
	return 0;
}

static int adc_open(struct inode *inode,struct file *filp)
{
	adc_initial();
	printk("ad convert opened!\n");
	return 0;
}
static int adc_release(struct inode *inode,struct file *filp)
{
	printk("ad convert closed!\n");
	return 0;
}
static void adc_setup_cdev(struct cdev *dev,int minor,
						   struct file_operations *fops)
{
	int err,devno=MKDEV(adc_major,minor);

	cdev_init(dev,fops);
	dev->owner=THIS_MODULE;
	dev->ops=fops;
	err=cdev_add(dev,devno,1);
	if(err)
		printk(KERN_NOTICE "Error %d adding adc %d",err,minor);
}
static struct cdev AdcDevs;
static struct file_operations adc_remap_ops={
	.owner=THIS_MODULE,
	.open=adc_open,
	.read=adc_read,
	.release=adc_release,
};

int __init
adc_init(void)
{
	int result;
	dev_t dev;

	if(adc_major) {
		dev=MKDEV(adc_major,0);
		result=register_chrdev_region(dev,1,DEVICE_NAME);
	}else {
		result=alloc_chrdev_region(&dev,0,1,DEVICE_NAME);
		adc_major=MAJOR(dev);
	}
	if(result<0) {
		printk(KERN_WARNING "adc:unable to get major %d\n",adc_major);
		return result;
	}
	adc_setup_cdev(&AdcDevs,0,&adc_remap_ops);
	printk("adc device installed,with major %d\n",adc_major);
	return 0;	
}

void __exit
adc_cleanup(void)
{
	cdev_del(&AdcDevs);
	unregister_chrdev_region(MKDEV(adc_major,0),1);
	printk("adc module exit\n");
	return ;
}
module_init(adc_init);
module_exit(adc_cleanup);