========================================================================== */
/*                                                                            */
/*   Filename.c                                                               */
/*   (c) 2001 Author  Zhang Haibo                                             */
/*                                                                            */
/*   Description  driver program with interrupt and poll                      */
/*                                                                            */
/* ========================================================================== */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/cdev.h>
#include <linux/kdev_t.h>
#include <asm/system.h>
#include <linux/poll.h>
#include <linux/irq.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/interrupt.h>
#include <mach/regs-gpio.h>
#include <mach/hardware.h>
#include <linux/gpio.h>

static struct class *cpld_class;                  //自動創(chuàng)建設備文件時需要先創(chuàng)建類
static struct class_device *cpld_class_dev;       //再創(chuàng)建驅(qū)動
static DECLARE_WAIT_QUEUE_HEAD(eint1_waitq);      //將中斷放入等待隊列
static struct fasync_struct *eint1_async;         //
static volatile int ev_eint1 = 0;                 //中斷標志，為1表示中斷發(fā)生，在中斷服務程序里置1
volatile unsigned long *cpld_data = NULL;         //CPLD的物理地址映射的虛擬地址指針  0x08000000
volatile unsigned long *gpfcon = NULL;            //GPF控制寄存器
volatile unsigned long *gpfdat = NULL;            //GPF數(shù)據(jù)寄存器，0位為使能位

static irqreturn_t eint1_irq(int irq, void *dev_id) //中斷服務程序
{
    ev_eint1 = 1;                                   //中斷標志位置1
    *gpfdat &= ~(1<<2);                             //進入中斷GPF2清0
    wake_up_interruptible(&eint1_waitq);            //喚醒休眠的進程
    kill_fasync (&eint1_async, SIGIO, POLL_IN);     //產(chǎn)生中斷后，驅(qū)動向應用程序發(fā)送信號     
    return IRQ_RETVAL(IRQ_HANDLED);
}

static int cpld_drv_open(struct inode *inode, struct file *file)
{
    request_irq(IRQ_EINT1,  eint1_irq, IRQ_TYPE_EDGE_FALLING, "EINT1", 1);//注冊中斷：中斷號，中斷程序入口，中斷方式，中斷名，代號
    return 0;
}
 
static ssize_t cpld_drv_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
{
    int val;
    *gpfdat &=~(1<<0);                //使能位置0，使能CPLD產(chǎn)生PWM，計數(shù)器開始計數(shù)
    copy_from_user(&val, buf, count); //產(chǎn)生PWM的值從用戶空間傳入
    iowrite16(val,cpld_data);         //寫入CPLD
    return 0;
}
 

static ssize_t cpld_drv_read(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
{
    int val;
    wait_event_interruptible(eint1_waitq, ev_eint1);  //若無中斷產(chǎn)生，即ev_eint1=0,則休眠
    val=ioread16(cpld_data);                          //若中斷產(chǎn)生，則從CPLD讀取數(shù)據(jù)，即編碼器值
    copy_to_user(buf,&val,count);                     //將讀取值傳遞到用戶空間
    ev_eint1 = 0;                                     //中斷標志清0
    *gpfdat |= (1<<2);                               //中斷讀數(shù)后，GPF2置1
    return 0;
} [!--empirenews.page--]

static unsigned cpld_drv_poll(struct file *file, poll_table *wait)
{
   unsigned int mask = 0;
   poll_wait(file, &eint1_waitq, wait);       //不會立即休眠
   if (ev_eint1)
   mask |= POLLIN | POLLRDNORM;               //若產(chǎn)生中斷，mask賦值，表示有數(shù)據(jù)可讀
   return mask;
}
 
static int cpld_drv_fasync (int fd, struct file *filp, int on)
{
 //printk("driver: cpld_drv_fasyncn");
 return fasync_helper (fd, filp, on, &eint1_async);
}

int cpld_drv_close(struct inode *inode, struct file *file)
{
    free_irq(IRQ_EINT1, 1);       //釋放中斷  
    return 0;
}
 
static struct file_operations cpld_drv_fops = {
    .owner    = THIS_MODULE,                  
    .write    = cpld_drv_write,
    .read     = cpld_drv_read,
    .open     = cpld_drv_open,
    .release  = cpld_drv_close,
    .poll     = cpld_drv_poll,
    .fasync   = cpld_drv_fasync,  
};
 

int major;
static int cpld_drv_init(void)
{
    major = register_chrdev(0, "cpld_drv", &cpld_drv_fops);                 //注冊設備
    cpld_class = class_create(THIS_MODULE, "cplddrv");                      //創(chuàng)建類
    cpld_class_dev = device_create(cpld_class, NULL, MKDEV(major, 0), NULL, "cpld_drv"); //自動創(chuàng)建設備文件 /dev/cpld_drv
    cpld_data = (volatile unsigned long *)ioremap(0x08000000,4);            //映射CPLD物理地址到虛擬地址
    gpfcon = (volatile unsigned long *)ioremap(0x56000050, 8);              //映射GPF寄存器物理地址到虛擬地址
    gpfdat = gpfcon+1;
    *gpfcon &=~((0x3<<0) | (0x3<<(2*2)));
    *gpfcon |=((0x1<<0) | (0x01<<(2*2)));     //設置GPF0、2為輸出
    *gpfdat |=0x1;          //將使能位置1，加載驅(qū)動時CPLD不輸出PWM
    printk("cpld_drv initialized!n");
    return 0;
}
 
static void cpld_drv_exit(void)
{
    *gpfdat |=0x1;          //將使能位置1，卸載驅(qū)動后CPLD不輸出PWM
    unregister_chrdev(major, "cpld_drv"); //注銷驅(qū)動
    device_unregister(cpld_class_dev);    //注銷設備
    class_destroy(cpld_class);            //注銷類
    iounmap(cpld_data);                   //取消映射
    iounmap(gpfcon);
}
 
module_init(cpld_drv_init);
module_exit(cpld_drv_exit);
 
MODULE_LICENSE("GPL");