第7个驱动程序

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/poll.h>
#include <mach/regs-gpio.h>
#include <mach/hardware.h>
#include <linux/irqreturn.h>
#include <linux/interrupt.h>
#include <linux/device.h>

static struct class *sixthdrv_class;
static struct class_device	*sixthdrv_class_dev;

//volatile unsigned long *gpfcon;
//volatile unsigned long *gpfdat;

static struct timer_list buttons_timer;

static DECLARE_WAIT_QUEUE_HEAD(button_waitq);

/* 中断事件标志, 中断服务程序将它置1，sixth_drv_read将它清0 */
static volatile int ev_press = 0;

static struct fasync_struct *button_async;

struct pin_desc{
unsigned int pin;
unsigned int key_val;
};

/* 键值: 按下时, 0x01, 0x02, 0x03, 0x04 */
/* 键值: 松开时, 0x81, 0x82, 0x83, 0x84 */
static unsigned char key_val;

/*
* K1,K2,K3,K4对应GPF1、GPF4、GPF2、GPF0
*/
struct pin_desc pins_desc[4] = {
{S3C2410_GPF1, 0x01},
{S3C2410_GPF4, 0x02},
{S3C2410_GPF2, 0x03},
{S3C2410_GPF0, 0x04},
};

static struct pin_desc *irq_pd;

//static atomic_t canopen = ATOMIC_INIT(1);     //定义原子变量并初始化为1

static DECLARE_MUTEX(button_lock);     //定义互斥锁

/*
* 确定按键值
*/
static irqreturn_t buttons_irq(int irq, void *dev_id)
{
/* 10ms后启动定时器 */
irq_pd = (struct pin_desc *)dev_id;
mod_timer(&buttons_timer, jiffies+HZ/100);
return IRQ_RETVAL(IRQ_HANDLED);
}

static int sixth_drv_open(struct inode *inode, struct file *file)
{
#if 0
if (!atomic_dec_and_test(&canopen))
{
atomic_inc(&canopen);
return -EBUSY;
}
#endif

if (file->f_flags & O_NONBLOCK)
{
if (down_trylock(&button_lock))
return -EBUSY;
}
else
{
/* 获取信号量 */
down(&button_lock);
}

/* GPF1、GPF4、GPF2、GPF0为中断引脚 */
request_irq(IRQ_EINT1, buttons_irq, IRQ_TYPE_EDGE_BOTH, "K1", &pins_desc[0]);
request_irq(IRQ_EINT4, buttons_irq, IRQ_TYPE_EDGE_BOTH, "K2", &pins_desc[1]);
request_irq(IRQ_EINT2, buttons_irq, IRQ_TYPE_EDGE_BOTH, "K3", &pins_desc[2]);
request_irq(IRQ_EINT0, buttons_irq, IRQ_TYPE_EDGE_BOTH, "K4", &pins_desc[3]);

return 0;
}

ssize_t sixth_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
if (size != 1)
return -EINVAL;

if (file->f_flags & O_NONBLOCK)
{
if (!ev_press)
return -EAGAIN;
}
else
{
/* 如果没有按键动作, 休眠 */
wait_event_interruptible(button_waitq, ev_press);
}

/* 如果有按键动作, 返回键值 */
copy_to_user(buf, &key_val, 1);
ev_press = 0;

return 1;
}

int sixth_drv_close(struct inode *inode, struct file *file)
{
//atomic_inc(&canopen);
free_irq(IRQ_EINT1, &pins_desc[0]);
free_irq(IRQ_EINT4, &pins_desc[1]);
free_irq(IRQ_EINT2, &pins_desc[2]);
free_irq(IRQ_EINT0, &pins_desc[3]);
up(&button_lock);
return 0;
}

static unsigned sixth_drv_poll(struct file *file, poll_table *wait)
{
unsigned int mask = 0;
poll_wait(file, &button_waitq, wait); // 不会立即休眠

if (ev_press)
mask |= POLLIN | POLLRDNORM;

return mask;
}

static int sixth_drv_fasync (int fd, struct file *filp, int on)
{
printk("driver: sixth_drv_fasync\n");
return fasync_helper (fd, filp, on, &button_async);
}

static struct file_operations sencod_drv_fops = {
.owner   =  THIS_MODULE,    /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */
.open    =  sixth_drv_open,
.read	 =	sixth_drv_read,
.release =  sixth_drv_close,
.poll    =  sixth_drv_poll,
.fasync	 =  sixth_drv_fasync,
};

int major;

static void buttons_timer_function(unsigned long data)
{
struct pin_desc * pindesc = irq_pd;
unsigned int pinval;

if (!pindesc)
return;

pinval = s3c2410_gpio_getpin(pindesc->pin);

if (pinval)
{
/* 松开 */
key_val = 0x80 | pindesc->key_val;
}
else
{
/* 按下 */
key_val = pindesc->key_val;
}

ev_press = 1;                  /* 表示中断发生了 */
wake_up_interruptible(&button_waitq);   /* 唤醒休眠的进程 */

kill_fasync (&button_async, SIGIO, POLL_IN);
}

static int sixth_drv_init(void)
{
init_timer(&buttons_timer);
buttons_timer.function = buttons_timer_function;
//buttons_timer.expires  = 0;
add_timer(&buttons_timer);

major = register_chrdev(0, "sixth_drv", &sencod_drv_fops);

sixthdrv_class = class_create(THIS_MODULE, "sixth_drv");

sixthdrv_class_dev = device_create(sixthdrv_class, NULL, MKDEV(major, 0), NULL, "buttons"); /* /dev/buttons */

//	gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);
//	gpfdat = gpfcon + 1;

return 0;
}

static void sixth_drv_exit(void)
{
unregister_chrdev(major, "sixth_drv");
device_unregister(sixthdrv_class_dev);
class_destroy(sixthdrv_class);
//	iounmap(gpfcon);
return 0;
}

module_init(sixth_drv_init);

module_exit(sixth_drv_exit);

MODULE_LICENSE("GPL");