Linux下CPLD驅(qū)動程序

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/*?? Filename.c?????????????????????????????????????????????????????????????? */
/*?? (c) 2001 Author? Zhang Haibo???????????????????????????????????????????? */
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/*?? Description? driver program with interrupt and poll????????????????????? */
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static struct class *cpld_class;????????????????? //自動創(chuàng)建設(shè)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;
}
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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;
}
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