buttons.c

linux下的矩阵式键盘驱动ppt教程与源码实例!

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/spinlock.h>
#include <linux/irq.h>
#include <linux/delay.h>

#include <asm/hardware.h>
#include <asm/irq.h>

#define DEVICE_NAME "buttons"
#define BUTTON_MAJOR 232

/*********************************************************
        4X4 矩阵键盘
四个输入引脚：  	EINT0 -----( GPF0  )----INPUT
                    EINT2 -----( GPF2  )----INPUT
                    EINT11-----( GPG3  )----INPUT
                    EINT19-----( GPG11 )----INPUT
                                                                                                                                               
四个输出引脚：  	KEYSCAN0---( GPE11 )----OUTPUT
                    KEYSCAN1---( GPG6  )----OUTPUT
                    KEYSCAN2---( GPE13 )----OUTPUT
                    KEYSCAN3---( GPG2  )----OUTPUT
**********************************************************/
/*
int Key_Scan( void )
{
	int returnvalue;
//delay
//	unsigned long j = jiffies +5;
//	while(jiffies<j);
//上锁
spin_lock_irq (&my_lock);
	GPGCON = GPGCON & (~((3<<22)|(3<<6))) | ((0<<22)|(0<<6)) ;            //GPG11,13 set input
        GPFCON = GPFCON & (~((3<<4)|(3<<0))) | ((0<<4)|(0<<0)) ;              //GPF2,0 set input

        //扫描键盘第4列 K16、K15、K14、K13
        GPGDAT = GPGDAT & (~((1<<6)|(1<<2))) | (1<<6) | (0<<2) ;                      //GPG6 output 1;GPG2 output 0
        GPEDAT = GPEDAT & (~((1<<13)|(1<<11))) | (1<<13) | (1<<11) ;          //GPE13 output 1;GPE11 output 1
        if(      (GPFDAT&(1<< 0)) == 0 )              { returnvalue= 16 ;goto out;}
        else if( (GPFDAT&(1<< 2)) == 0 )              { returnvalue= 15 ;goto out;}
        else if( (GPGDAT&(1<< 3)) == 0 )              { returnvalue= 14 ;goto out;}
        else if( (GPGDAT&(1<<11)) == 0 )              { returnvalue= 13 ;goto out;}
                                                                                                                                               
        //扫描键盘第2列 K11、K8、K5、K2
        GPGDAT = GPGDAT & (~((1<<6)|(1<<2))) | (0<<6) | (1<<2) ;                  //GPG6 output 0;GPG2 output 1
        GPEDAT = GPEDAT & (~((1<<13)|(1<<11))) | (1<<13) | (1<<11) ;          //GPE13 output 1;GPE11 output 1
        if(      (GPFDAT&(1<< 0)) == 0 )              { returnvalue= 11;goto out;}
        else if( (GPFDAT&(1<< 2)) == 0 )              { returnvalue= 8 ;goto out;}
        else if( (GPGDAT&(1<< 3)) == 0 )              { returnvalue= 5 ;goto out;}
        else if( (GPGDAT&(1<<11)) == 0 )              { returnvalue= 2 ;goto out;}
                                                                                                                                               
        //扫描键盘第1列 K10、K7、K4、K1
        GPGDAT = GPGDAT & (~((1<<6)|(1<<2))) | (1<<6) | (1<<2) ;                      //GPG6 output 1;GPG2 output 1
        GPEDAT = GPEDAT & (~((1<<13)|(1<<11))) | (1<<13) | (0<<11) ;          //GPE13 output 1;GPE11 output 0
        if(      (GPFDAT&(1<< 0)) == 0 )              { returnvalue= 10;goto out;} 
        else if( (GPFDAT&(1<< 2)) == 0 )              { returnvalue= 7; goto out;} 
        else if( (GPGDAT&(1<< 3)) == 0 )              { returnvalue= 4; goto out;}
        else if( (GPGDAT&(1<<11)) == 0 )              { returnvalue= 1; goto out;}
                                                                                                                                               
        //扫描键盘第3列 K12、K9、K6、K3
        GPGDAT = GPGDAT & (~((1<<6)|(1<<2))) | (1<<6) | (1<<2) ;                      //GPG6 output 1;GPG2 output 1
        GPEDAT = GPEDAT & (~((1<<13)|(1<<11))) | (0<<13) | (1<<11) ;          //GPE13 output 0;GPE11 output 1
        if(      (GPFDAT&(1<< 0)) == 0 )               returnvalue= 12 ;
        else if( (GPFDAT&(1<< 2)) == 0 )               returnvalue= 9 ;
        else if( (GPGDAT&(1<< 3)) == 0 )               returnvalue= 6 ;
        else if( (GPGDAT&(1<<11)) == 0 )               returnvalue= 3 ;
        else returnvalue= 0xff ;
out:        //重新初始化IO口
        GPGCON = GPGCON & (~((3<<12)|(3<<4))) | ((1<<12)|(1<<4)) ;            //GPG6,2 set output
        GPGDAT = GPGDAT & (~((1<<6)|(1<<2)));         //GPG6,2 output 0
                                                                                                                                              
        GPECON = GPECON & (~((3<<26)|(3<<22))) | ((1<<26)|(1<<22));           //GPE13,11 set output
        GPEDAT = GPEDAT & (~((1<<13)|(1<<11)));               //GPE13,11 output 0
                                                                                                                                               
        GPGCON = GPGCON & (~((3<<22)|(3<<6))) | ((2<<22)|(2<<6)) ;            //GPG11,3 set EINT
        GPFCON = GPFCON & (~((3<<4)|(3<<0))) | ((2<<4)|(2<<0)) ;              //GPF2,0 set EINT

spin_lock_irq (&my_lock);
//解锁
	return returnvalue;
}
*/
static struct key_info {
	int irq_no;
	unsigned int gpio_port;
	unsigned int gpio_port_kscan;
	int key_no;
} key_info_tab[16] = {
	/*键盘第1列 k10 k7 k4 k1*/
	{ IRQ_EINT19, GPIO_G11, GPIO_E11, 1 },
	{ IRQ_EINT11, GPIO_G3, GPIO_E11, 4 },
	{ IRQ_EINT2, GPIO_F2, GPIO_E11, 7 },
	{ IRQ_EINT0, GPIO_F0, GPIO_E11, 10 },
	
	/*键盘第2列 k11 k8 k5 k2*/
	{ IRQ_EINT19, GPIO_G11, GPIO_G6, 2 },
	{ IRQ_EINT11, GPIO_G3, GPIO_G6, 5 },
	{ IRQ_EINT2, GPIO_F2, GPIO_G6, 8 },
	{ IRQ_EINT0, GPIO_F0, GPIO_G6, 11 },
	
	/*键盘第3列 k12 k9 k5 k3*/
	{ IRQ_EINT19, GPIO_G11, GPIO_E13, 3 },
	{ IRQ_EINT11, GPIO_G3, GPIO_E13, 6 },
	{ IRQ_EINT2, GPIO_F2, GPIO_E13, 9 },
	{ IRQ_EINT0, GPIO_F0, GPIO_E13, 12 },
	
	/*键盘第4列 k16 k15 k14 k13*/
	{ IRQ_EINT19, GPIO_G11, GPIO_G2, 13 },
	{ IRQ_EINT11, GPIO_G3, GPIO_G2, 14 },
	{ IRQ_EINT2, GPIO_F2, GPIO_G2, 15 },
	{ IRQ_EINT0, GPIO_F0, GPIO_G2, 16 },
};

static int eint[4] = {IRQ_EINT19, IRQ_EINT11, IRQ_EINT2, IRQ_EINT0};
static unsigned int ioport[4] = {GPIO_G11, GPIO_G3, GPIO_F2, GPIO_F0};
static unsigned int kscan[4] = {GPIO_E11, GPIO_G6, GPIO_E13, GPIO_G2};

static int ready = 0;
static int key_value = 0;

/*初始化按键的等待队列*/
static DECLARE_WAIT_QUEUE_HEAD(buttons_wait);

/* 初始化kscan口为输出0 */
static void buttons_io_port_init(void)
{
	int i;

	for(i=0; i < sizeof kscan / sizeof kscan[1]; i++) {
		set_gpio_ctrl(kscan[i] | GPIO_PULLUP_DIS | GPIO_MODE_OUT);
		write_gpio_bit(kscan[i], 0);
	}
}

/* 设置单个kscan口为输出0 */
static void buttons_kscan_reset(int column)
{
	int i;

	for(i=0; i < sizeof kscan / sizeof kscan[1]; i++) {
		if(i == column)
			write_gpio_bit(kscan[i], 0);
		else
			write_gpio_bit(kscan[i], 1);
	}
}

/* 设置GPIO口为输入状态 */
static void buttons_port_reset(void)
{
	int i;

	for(i=0; i < sizeof ioport / sizeof ioport[1]; i++) {
		set_gpio_ctrl(ioport[i] | GPIO_PULLUP_DIS | GPIO_MODE_IN);
	}
}

/* 重新设置中断 */
static void buttons_int_reset(void)
{
	int i;

	for(i=0; i < sizeof eint / sizeof eint[1]; i++) {
		set_external_irq(eint[i], EXT_FALLING_EDGE, GPIO_PULLUP_DIS);
	}
}

static void buttons_irq(int irq, void *dev_id, struct pt_regs *reg)
{
	struct key_info *k;
	int i, j;
	int found = 0;
	int up = -1;
	int column = 0;
	int row = 0;
	
	buttons_port_reset();    /* 设置GPIO为输入状态 */
	
	udelay(10000); /*延时10000us*/
	/* 键盘扫描 */
	for ( j = 0; j < sizeof kscan / sizeof kscan[1]; j++) {
		buttons_kscan_reset(j);
		column = j;

		for ( i = 0; i < sizeof eint / sizeof eint[1]; i++) {
			if(eint[i] == irq) {
				row = i;
				up = read_gpio_bit(ioport[i]);
				break;
			}
		}

		if(up == 0) {
			found = 1;
			break;
		}
	}
	udelay(10000);                              /* 延时去抖 */
	
	if (found) {
		k = key_info_tab + column * 4 + row;

		if (up) {
			key_value = k->key_no + 0x80;//
		} else {
			key_value = k->key_no;
		}
	}
	
	ready = 1;
	wake_up_interruptible(&buttons_wait);

	buttons_io_port_init();     /* 重新设置GPIO为输出 */
	buttons_int_reset();        /* 重新设置中断 */
}

static int request_irqs(void)
{
	int i;
	
	for (i = 0; i < sizeof eint / sizeof eint[1]; i++) {
		set_external_irq(eint[i], EXT_FALLING_EDGE, GPIO_PULLUP_DIS);
		 //设置与外部中断号相对应的GPIO端口，下降沿触发，上拉寄存器是禁止的
		if (request_irq(eint[i], &buttons_irq, SA_INTERRUPT, DEVICE_NAME, &buttons_irq)) {
			return -1;
		}	/*请求中断，所有的按键都使用同一个中断处理程序。中断处理程序根据中断号确定按下的是哪一个按键。*/
	}

	return 0;
}

static void free_irqs(void)
{
	int i;
	
	for (i = 0; i < sizeof eint / sizeof eint[1]; i++)
		free_irq(eint[i], buttons_irq);
}

static int matrix4_buttons_read(struct file * file, char * buffer, size_t count, loff_t *ppos)
{
	static int key;
	int flags;
	int repeat;
	
	if (!ready)
		return -EAGAIN;
		
	if (count != sizeof key_value)
		return -EINVAL;
		
	save_flags(flags); //没有必要
	
	if (key != key_value) {
		key = key_value;
		repeat = 0;
	} else {
		repeat = 1;
	}
	
	restore_flags(flags);
	
	/*if (repeat) {
		return -EAGAIN;
	}*/
	
	copy_to_user(buffer, &key, sizeof key);
	ready = 0;
	
	return sizeof key_value;
}

static unsigned int matrix4_buttons_select(struct file *file, struct poll_table_struct *wait)
{
	if (ready)
		return 1;
		
	poll_wait(file, &buttons_wait, wait); 
	//通过调用函数 poll_wait,增加buttons_wait等待队列到poll_table 结构。
	//poll 方法是 3 个系统调用的后端: poll, epoll, 和 select.(from ldd)
	// 用作查询对一个或多个文件描述符的
	
	return 0;
}

static int matrix4_buttons_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
	switch(cmd) {
	default:
		return -EINVAL;
	}
}

static struct file_operations matrix4_buttons_fops = {
	owner: THIS_MODULE,
	ioctl: matrix4_buttons_ioctl,
	poll:  matrix4_buttons_select,
	read:  matrix4_buttons_read,
};

static devfs_handle_t devfs_handle;

static int __init matrix4_buttons_init(void)
{
	int ret;
	ready = 0;
	ret = register_chrdev(BUTTON_MAJOR, DEVICE_NAME, &matrix4_buttons_fops);
	
	if (ret < 0) {
		printk(DEVICE_NAME " can't register major number\n");
		return ret;
	}
	buttons_io_port_init();
	
	ret = request_irqs();
	if (ret) {
		unregister_chrdev(BUTTON_MAJOR, DEVICE_NAME);
		printk(DEVICE_NAME " can't request irqs\n");
		return ret;
	}
	
	devfs_handle = devfs_register(NULL, DEVICE_NAME, DEVFS_FL_DEFAULT, BUTTON_MAJOR, 0, S_IFCHR | S_IRUSR | S_IWUSR, &matrix4_buttons_fops, NULL);
	
	return 0;
}

static void __exit matrix4_buttons_exit(void)
{
	devfs_unregister(devfs_handle);
	free_irqs();
	unregister_chrdev(BUTTON_MAJOR, DEVICE_NAME);
}

module_init(matrix4_buttons_init);
module_exit(matrix4_buttons_exit);
MODULE_LICENSE("GPL");