/*=========================================================================
? 工程名稱： 3_AD_driver?
? 組成文件： voltage_driver.c
? 功能描述： 測(cè)試0~3.3V間電壓，練習(xí)AD采樣應(yīng)用編程
? 硬件連接： 引出AIN0~3四個(gè)通道
=========================================================================*/


#include <linux/module.h> ? ?/*module_init()*/
#include <linux/kernel.h> /* printk() */
#include <linux/init.h> /* __init __exit */
#include <linux/fs.h> /* file_operation */
#include <asm/uaccess.h> /* copy_to_user, copy_from_user */
#include <linux/device.h> ?/*class ,class_create ,device_create 等*/
#include <linux/errno.h> /* Error number */
#include <linux/delay.h> /* mdelay ,ndelay*/
#include <asm/delay.h> ? ? /* udelay */
#include <mach/regs-gpio.h> ?/*S3C2410_GPGCON*/
#include <linux/pci.h> /*S3C24XX_VA_GPIO*/


#include <linux/irq.h> //set_irq_type ,IRQ_TYPE_EDGE_FALLING
#include <linux/interrupt.h> //request_irq , free_irq
#include <plat/regs-adc.h> ? // S3C2410_ADCCON
#include <asm/io.h> //ioremap()
#include <linux/clk.h> //clk_get() , clk_enable()


#define DEBUG //open debug message


#ifdef DEBUG
#define PRINTK(fmt, arg...) printk(KERN_WARNING fmt, ##arg)
#else
#define PRINTK(fmt, arg...) printk(KERN_DEBUG fmt, ##arg)
#endif


#define DRIVER_NAME "volt_driver"


#define ADCCON ? (*(volatile unsigned long *)(regs_adc + S3C2410_ADCCON)) //ADC control
#define ADCDLY ? (*(volatile unsigned long *)(regs_adc + S3C2410_ADCDLY)) //ADC start or Interval Delay
#define ADCDAT0 ?(*(volatile unsigned long *)(regs_adc + S3C2410_ADCDAT0))


static void __iomem *regs_adc;


static int MAJOR_NR = 0; /* Driver Major Number */
static int MINOR_NR = 0; //次設(shè)備起始號(hào)
struct class *my_class;


static void initADIO(void)
{
unsigned char ch=0;

? ADCDLY = 100; //ADC轉(zhuǎn)換延時(shí)
ADCCON = ? ?(0 << 0) ? ? | // ADC轉(zhuǎn)換暫不啟動(dòng)
? ? ? ? ? ?(0 << 1) ? ? | ?// 使能通過(guò)讀AD數(shù)據(jù)觸發(fā)AD轉(zhuǎn)換
? ? ? ? ? ?(0 << 2) ? ? | ?// StandBy模式選擇
? ? ? ? ? ?(ch << 3) ? ?| ?// ADC通道選擇 ch
? ? ? ? ? ?(49 << 6) ? ?| // CLKDIV = Fpclk(50M) /49+1，即轉(zhuǎn)換時(shí)鐘為1MHz
? ? ? ? ? ?(1 << 14) ? ; // 使能軟件預(yù)設(shè)值


//ADCCON = (0<<0)|(0<<1)|(0<<2)|(ch<<3)|(49<<6)|(1<<14);
}


//=========================================================================
//名稱：AD_ENABLE()
//功能：采用置位使能方式啟動(dòng)AD轉(zhuǎn)換
//參數(shù): 無(wú)
//返回值: 無(wú)
//=========================================================================
static int getad_enable(void)?
{
int i,j;
int val=0;
unsigned con;


for(i=0;i<16;i++)
{
ADCCON |= 0x1; //使能ADC 轉(zhuǎn)換
while(ADCCON&0x1); //判斷是否使能ADC轉(zhuǎn)換
while(!ADCCON&0x8000); //判斷ADC轉(zhuǎn)換是否結(jié)束
val += (ADCDAT0 &0x03ff); //取出ADC轉(zhuǎn)換值

for(j=0;j<500;j++);
}
val = val/16; //計(jì)算ADC平均轉(zhuǎn)換值


return val;
}


//=========================================================================
//名稱：AD_READ()
//功能：采用讀控制器的方式啟動(dòng)AD轉(zhuǎn)換
//參數(shù): 無(wú)
//返回值: 無(wú)
//=========================================================================
static int ?getad_read (void)?
{
int i,j;
int val;


ADCCON |= 0x2; ? ? ? ? ? ? //ADC轉(zhuǎn)換通過(guò)讀操作來(lái)啟動(dòng)
val = ADCDAT0 &0x03ff; //啟動(dòng)ADC轉(zhuǎn)換
val = 0;
?
for(i=0;i<16;i++)
{
while(!ADCCON&0x8000); //判斷ADC轉(zhuǎn)換是否結(jié)束
val += (ADCDAT0 &0x03ff); ? ?//取出ADC轉(zhuǎn)換值
for(j=0;j<500;j++); ? ? ??
}
val = val/16; ? ? ? ? ? ? ? ? ? //計(jì)算ADC平均轉(zhuǎn)換值
return val;
}


/* Driver Operation Functions */
static int myDriver_open(struct inode *inode, struct file *filp)
{
int err;
struct clk *adc_clk;

PRINTK("myDriver open called!\n");

adc_clk = clk_get(NULL, "adc");
? ? if(!adc_clk)
? ? {
? ? ? ? /*錯(cuò)誤處理*/
? ? ? ? PRINTK("falied to find adc clock source\n");
clk_disable(adc_clk);
clk_put(adc_clk);
? ? ? ? return -ENOENT;
? ? }
? ? clk_enable(adc_clk);
//S3C2410_PA_ADC是ADC控制器的基地址0x58000000，
//定義在mach-s3c2410/include/mach/map.h中
//0x20是虛擬地址長(zhǎng)度大小(總寄存器占地址空間長(zhǎng)度)
regs_adc = ioremap(S3C2410_PA_ADC, 0x20); //得到虛地址偏移量
initADIO();
return 0;
}


static int myDriver_release(struct inode *inode, struct file *filp)
{
PRINTK("myDriver release called!\n");
/*釋放虛擬地址映射空間*/
? ? iounmap(regs_adc);
return 0;
}


static ssize_t myDriver_read(struct file *filp, char *buf, size_t count, loff_t *f_pos)
{
int ret = 0;
volatile int value;
volatile int voltage;
volatile unsigned char temp[2];

//value = getad_read();
value = getad_enable();
voltage = 330*value/1024;//voltage/3.3 = value/1024=>voltage=(3.3*value)/1024)*100(為了方便計(jì)算放大100倍)

temp[0] = voltage&0xff;
temp[1] = (voltage>>8)&0xff;
ret = copy_to_user(buf, &temp, 2);


return ret;
}


/* Driver Operation structure */
static struct file_operations myDriver_fops = {
owner: THIS_MODULE,
read: myDriver_read,
open: myDriver_open,
release: myDriver_release,
};


static int __init myModule_init(void)
{
/* Module init code */
PRINTK("ADdriver_init\n");
/* Driver register */
MAJOR_NR = register_chrdev(MAJOR_NR, DRIVER_NAME, &myDriver_fops);
if(MAJOR_NR < 0)
{
PRINTK("register char device fail!\n");
return MAJOR_NR;
}
my_class=class_create(THIS_MODULE,"udev_AD");
device_create(my_class,NULL, MKDEV(MAJOR_NR, MINOR_NR), NULL,DRIVER_NAME);

PRINTK("register myDriver OK! Major = %d\n", MAJOR_NR);
return 0;
}


static void __exit myModule_exit(void)
{
/* Module exit code */
PRINTK("exit in\n");
/* Driver unregister */
if(MAJOR_NR > 0)
{
unregister_chrdev(MAJOR_NR, DRIVER_NAME);
device_destroy(my_class,MKDEV(MAJOR_NR, MINOR_NR));
class_destroy(my_class);
PRINTK("myModule_exit ok\n");
}
return;
}


module_init(myModule_init);
module_exit(myModule_exit);


MODULE_LICENSE("GPL");
MODULE_AUTHOR("xiuhai");

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