pcDuino Linux驱动开发四 -- 最简单的中断驱动

tjcfeng · 发表于 2014-11-30 23:13:49

基于前面提到的最精简的框架，中断程序只是多了一个irq注册和响应的代码。
需要增加的函数有：
request_irq //请求注册irq
free_irq //释放请求
和一个自定义的irq响应函数。
当然，为了程序能够真正完成工作，还需要一个阻塞响应机制，以便用户程序能够等到中断的到达。
这里同样使用了最简单的方式，增加的函数：
DECLARE_COMPLETION(MSG); //linux内核定义好的宏，给一个变量名称即可
init_completion(&MSG); //初始化
wait_for_completion(&MSG); //阻塞函数
complete(&MSG); //打断阻塞的函数
下面上代码，对照之前的GPIO框架，可以很清晰地看出区别：

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <linux/interrupt.h>
#include "../A10.h"
/**********************************************************************/
#define KEY_IRQ 28
#define KEY_BACK 17
#define KEY_HOME 19
#define KEY_MENU 18
#define KEY_BACK_BIT 0x20000 //(0x1 << 17)
#define KEY_MENU_BIT 0x40000 //(0x1 << 18)
#define KEY_HOME_BIT 0x80000 //(0x1 << 19)
#define KEY_DOWN 0
#define KEY_UP 1
volatile static unsigned long* REG_PH_CFG2;
volatile static unsigned long* REG_PH_PULL1;
volatile static unsigned long* REG_PIO_INT_CFG2;
volatile static unsigned long* REG_PIO_INT_CTL;
volatile static unsigned long* REG_PIO_INT_STATUS;
volatile static unsigned long* REG_PH_DAT;
/*volatile static unsigned long* REG_INTC_IRQ_PEND_REG0;
volatile static unsigned long* REG_INTC_IRQ_TYPE_SEL0;
volatile static unsigned long* REG_INTC_EN_REG0;
volatile static unsigned long* REG_INTC_MASK_REG0;*/
static int Inited = 0;
DECLARE_COMPLETION(MSG);
static unsigned char KeyFlag = 0;
static unsigned char KeyHL = 255;
static irqreturn_t KEY_ISR(int irq, void* dev_id)
{
unsigned int State, Data;
State = *REG_PIO_INT_STATUS;
*REG_PIO_INT_STATUS |= (KEY_HOME_BIT + KEY_MENU_BIT + KEY_BACK_BIT); //Clear INT Pending
mdelay(1);
*REG_PH_CFG2 &= ~((0x7 << 12) + (0x7 << 8) + (0x7 << 4)); //Input
Data = *REG_PH_DAT;
*REG_PH_CFG2 |= ((0x6 << 12) + (0x6 << 8) + (0x6 << 4)); //EINT
//printk("IRQ State - %u ___ IRQ Data - %u\n", State, Data);
if ((State & KEY_BACK_BIT) == KEY_BACK_BIT )
{
KeyFlag = KEY_BACK;
if ((Data & KEY_BACK_BIT) == KEY_BACK_BIT) KeyHL = KEY_UP; else KeyHL = KEY_DOWN;
}
else
if ((State & KEY_MENU_BIT) == KEY_MENU_BIT)
{
KeyFlag = KEY_MENU;
if ((Data & KEY_MENU_BIT) == KEY_MENU_BIT) KeyHL = KEY_UP; else KeyHL = KEY_DOWN;
}
else
if ((State & KEY_HOME_BIT) == KEY_HOME_BIT)
{
KeyFlag = KEY_HOME;
if ((Data & KEY_HOME_BIT) == KEY_HOME_BIT) KeyHL = KEY_UP; else KeyHL = KEY_DOWN;
}
if ((KeyFlag != 0) && (KeyHL != 255)) complete(&MSG);
return IRQ_HANDLED;
}
static int KEY_open(struct inode* n, struct file* f)
{
int Result = 0;
Inited++;
if (Inited > 1)
{
return 0;
}
REG_PH_CFG2 = (volatile unsigned long*) ioremap(PH_CFG2, 4);
REG_PH_PULL1 = (volatile unsigned long*) ioremap(PH_PULL1, 4);
REG_PIO_INT_CFG2 = (volatile unsigned long*) ioremap(PIO_INT_CFG2, 4);
REG_PIO_INT_CTL= (volatile unsigned long*) ioremap(PIO_INT_CTL, 4);
REG_PIO_INT_STATUS = (volatile unsigned long*) ioremap(PIO_INT_STATUS, 4);
REG_PH_DAT = (volatile unsigned long*) ioremap(PH_DAT, 4);
/*REG_INTC_IRQ_PEND_REG0 = (volatile unsigned long*) ioremap(INTC_IRQ_PEND_REG0, 4);
REG_INTC_IRQ_TYPE_SEL0 = (volatile unsigned long*) ioremap(INTC_IRQ_TYPE_SEL0, 4);
REG_INTC_EN_REG0 = (volatile unsigned long*) ioremap(INTC_EN_REG0, 4);
REG_INTC_MASK_REG0 = (volatile unsigned long*) ioremap(INTC_MASK_REG0, 4);*/
*REG_PH_CFG2 &= ~((0x7 << 12) + (0x7 << 8) + (0x7 << 4));
*REG_PH_CFG2 |= ((0x6 << 12) + (0x6 << 8) + (0x6 << 4)); //EINT
*REG_PH_PULL1 &= ~((0x3 << 6) + (0x3 << 4) + (0x3 << 2));
*REG_PH_PULL1 |= ((0x1 << 6) + (0x1 << 4) + (0x1 << 2)); //Pull_UP
*REG_PIO_INT_CFG2 &= ~((0xF << 12) + (0xF << 8) + (0xF << 4));
*REG_PIO_INT_CFG2 |= ((0x4 << 12) + (0x4 << 8) + (0x4<< 4)); //Double Edge
//*REG_PH_DAT |= KEY_HOME_BIT + KEY_MENU_BIT + KEY_BACK_BIT;
//*REG_INTC_IRQ_TYPE_SEL0 &= ~((0x1 << KEY_MENU) + (0x1 << KEY_HOME) + (0x1 << KEY_BACK)); //Is IRQ, not FIQ
//*REG_INTC_EN_REG0 |= ((0x1 << KEY_MENU) + (0x1 << KEY_HOME) + (0x1 << KEY_BACK)); //Enable INT
*REG_PIO_INT_CTL |= ((0x1 << KEY_MENU) + (0x1 << KEY_HOME) + (0x1 << KEY_BACK)); //Enable INT
Result = request_irq(KEY_IRQ, KEY_ISR, IRQF_DISABLED, "KEY", NULL);
if (Result != 0)
{
//printk("Request IRQ file! ErrorCode: %d\n", Result);
free_irq(KEY_IRQ, NULL);
return Result;
}
init_completion(&MSG);
//printk("Open Finished!\n");
return Result;
}
static ssize_t KEY_write(struct file* f, const char __user* buf, size_t len, loff_t* l)
{
unsigned char Buf[2];
if (copy_from_user(&Buf, buf, len)) return -1;
//printk("Write Finished!\n");
return len;
}
static ssize_t KEY_read(struct file* f, char __user* buf, size_t len, loff_t* l)
{
unsigned char Buf[2];
int Len = sizeof(Buf);
wait_for_completion(&MSG);
Buf[0] = KeyFlag;
Buf[1] = KeyHL;
if (copy_to_user(buf, &Buf, sizeof(Buf))) return 0;
KeyFlag = 0;
KeyHL = 255;
//printk("Read Finished!\n");
return Len;
}
static int KEY_close(struct inode* n, struct file* f)
{
Inited--;
if (Inited > 0)
{
return 0;
}
free_irq(KEY_IRQ, NULL);
//remove_wait_queue(&MSG);
iounmap(REG_PH_CFG2);
iounmap(REG_PH_PULL1);
iounmap(REG_PIO_INT_CFG2);
iounmap(REG_PIO_INT_STATUS);
iounmap(REG_PH_DAT);
/*iounmap(REG_INTC_IRQ_PEND_REG0);
iounmap(REG_INTC_IRQ_TYPE_SEL0);
iounmap(REG_INTC_EN_REG0);
iounmap(REG_INTC_MASK_REG0);*/
//printk("Close Finished!\n");
return 0;
}
/**********************************************************************/
#define DEV_NAME "KEY"
#define DEV_COUNT 1
static struct class* pClass;
int major;
static struct file_operations fops =
{
.owner = THIS_MODULE,
.open = KEY_open,
.write = KEY_write,
.read = KEY_read,
.release = KEY_close,
};
static int __init KEY_init(void)
{
major = register_chrdev(0, DEV_NAME, &fops);
pClass = class_create(THIS_MODULE, DEV_NAME);
if (pClass == NULL)
{
unregister_chrdev(major, DEV_NAME);
return -1;
}
device_create(pClass, NULL, MKDEV(major, 0), NULL, DEV_NAME);
//printk("Init Finished!\n");
return 0;
}
static void __exit KEY_exit(void)
{
unregister_chrdev(major, DEV_NAME);
if (pClass)
{
device_destroy(pClass, MKDEV(major, 0));
class_destroy(pClass);
}
//printk("Exit Finished!\n");
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("LiuYang");
module_init(KEY_init);
module_exit(KEY_exit);

复制代码
Makefile文件同前，改一下文件名.o即可。
测试程序：

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
int main(int argc, char **argv)
{
int f;
int I;
int Len;
unsigned char Buf[2];
f = open("/dev/KEY", O_RDWR);
printf("File Handle: %d\n", f);
if (f < 0)
{
printf("Open KEY fail!\n");
return -1;
}
for (I = 0; I < 6; I++)
{
Len = read(f, &Buf, 2);
printf("Len: %d -- Key: %d -- HL: %d\n", Len, Buf[0], Buf[1]);
}
close(f);
return 0;
}

复制代码
这样，测试程序在调用了read之后会阻塞在那里，等待驱动程序中中断的达到。每次按下按键后，程序就继续执行了。wait_for_completion有很多种，可以增加超时之类的来完成自己的要求。
顺便说一下，pcDuino已经占用了这个中断，测试的话，在启动后需要先rmmod sw_interrupt，以保证本程序的运行。

pcDuino Linux驱动开发四 -- 最简单的中断驱动

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