mini2440等待队列方式的ADC驱动
#有奖活动# #申请开发板# #申请原创# #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 <linux/wait.h>
#include <linux/sched.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 "char/s3c24xx-adc.h"
#undef DEBUG
//#define DEBUG
#ifdef DEBUG
#define DPRINTK(x...) {printk(__FUNCTION__"(%d): ",__LINE__);printk(##x);}
#else
#define DPRINTK(x...) (void)(0)
#endif
#define DEVICE_NAME "adc_test"
static void __iomem *base_addr;
typedef struct {
wait_queue_head_t wait_queue_finish_ADC_conver;//定义等待队列头,生成一个等待队列头
int channel;
int prescale;
}ADC_DEV;
//DECLARE_MUTEX(ADC_LOCK_mutex);//静态定义Mutex(互斥量),Mutex属于sleep-waiting类型的锁。
static DEFINE_MUTEX(ADC_LOCK_mutex);
//动态定义mutex_init(&mutex);
//struct mutex ADC_LOCK_mutex;
static int OwnADC = 0;
static ADC_DEV adcdev;
static volatile int ev_adc = 0;
static int adc_data;
static struct clk *adc_clock;
#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 voidSTART_ADC_AIN(int ch, int prescale)
{
ADCCON = (PRESCALE_EN) | PRSCVL(prescale) | ADC_INPUT(ch);
ADCCON |= ADC_START;
}
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_queue_finish_ADC_conver);
}
return IRQ_HANDLED;
}
static ssize_t s3c2410_adc_read(struct file *filp, int *buffer, size_t count, loff_t *ppos)
{
int value;
int ret;
mutex_lock(&ADC_LOCK_mutex);//为指定的mutex上锁，如果不可用则睡眠
{
OwnADC = 1;
START_ADC_AIN(adcdev.channel, adcdev.prescale);
/*
wait_event_interruptible_timeout(wq, condition, timeout)
* 函数作用：~睡眠~,直到condition为真，或timeout超时；
* @wq: 要等待的等待队列
* @condition: 等待事件发生的条件（一个C表达式 ）
* @timeout: 超时时间
*/
wait_event_interruptible(adcdev.wait_queue_finish_ADC_conver, ev_adc);
adc_data = ADCDAT0 & 0x3ff;
ev_adc = 0;
value = adc_data;
OwnADC = 0;
}
mutex_unlock(&ADC_LOCK_mutex); //为指定的mutex解锁
ret = copy_to_user(buffer, &value, sizeof(value));
return ret;
}
static ssize_t s3c2410_adc_open(struct inode *inode, struct file *filp)
{
init_waitqueue_head(&(adcdev.wait_queue_finish_ADC_conver));//初始化等待队列
adcdev.channel=0;
adcdev.prescale=0xff;
DPRINTK( "adc opened\n");
return 0;
}
static int s3c2410_adc_release(struct inode *inode, struct file *filp)
{
DPRINTK( "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 ADC_dev_init(void)
{
int ret;
base_addr=ioremap(S3C2410_PA_ADC,0x20);//0x20长度是字节长度，不是寄存器个数
if (base_addr == NULL)
{
printk(KERN_ERR "Failed to remap ADC register block\n");
return -ENOMEM;
}
//clk_get从一个时钟list链表中以字符id名称来查找一个时钟clk结构体并且返回，最后调用clk.enable()，来时能对应的外设时钟源。
adc_clock = clk_get(NULL, "adc");
if (!adc_clock)
{
printk(KERN_ERR "failed to get adc clock source\n");
return -ENOENT;
}
clk_enable(adc_clock);
/* normal ADC */
ADCTSC = 0;
/*
参数1：中断线号(多个设备共享同一个中断线号)
参数2：中断处理程序函数指针
参数3：标志掩码(SA_INTERRUPT, SA_SAMPLE_RANDOM, SA_SHIRQ)
参数4：用于参数3为SA_SHIRQ(共享中断线)的时候，其他为NULL,多个设备共享同一个中断线号，当中断产生的时候到底是那一个设备 产生的中断呢，这个就取决于第四个参数dev_id
*/
ret = request_irq(IRQ_ADC, adcdone_int_handler, IRQF_SHARED, DEVICE_NAME, &adcdev);
if (ret) //非0代表有错误
{
iounmap(base_addr);
printk ("request_irq return error");
return ret;
}
ret = misc_register(&misc);
printk(DEVICE_NAME"\ finish initialized\n");
//mutex_init(&ADC_LOCK_mutex);//动态定义mutex类型的时候应用此函数初始化
return ret;
}
static void __exit ADC_dev_exit(void)
{
free_irq(IRQ_ADC, &adcdev);
iounmap(base_addr);
if (adc_clock)
{
clk_disable(adc_clock);
clk_put(adc_clock);
adc_clock = NULL;
}
misc_deregister(&misc);
}
EXPORT_SYMBOL(ADC_LOCK_mutex);
module_init(ADC_dev_init);
module_exit(ADC_dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("FriendlyARM Inc.");
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