linux下4x4矩阵 键盘驱动，用了定时器控制扫描程序来抗抖。

折磨了好几天，终于调试稳定了。

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/delay.h>

#include <linux/poll.h>

#include <linux/irq.h>

#include <asm/irq.h>

#include <linux/interrupt.h>

#include <asm/uaccess.h>

#include <mach/regs-gpio.h>

#include <mach/hardware.h>

#include <linux/platform_device.h>

#include <linux/cdev.h>

#include <linux/miscdevice.h>

#include <linux/sched.h>

#include <linux/gpio.h>

#include <linux/signal.h>

#include <linux/timer.h>

#define DEVICE_NAME "buttons"

struct button_irq_desc {

int irq;

int pin;

int pin_setting;

int number;

char *name;

};

static unsigned long led_table [] = {

S3C2410_GPF(0),

S3C2410_GPF(1),

S3C2410_GPF(4),

S3C2410_GPF(6),

};

static struct button_irq_desc button_irqs [] = {

{IRQ_EINT5 ,S3C2410_GPF(5) , S3C2410_GPF5_EINT5 , 0, "KEY0"},

{IRQ_EINT3, S3C2410_GPF(3) , S3C2410_GPF3_EINT3 , 1, "KEY1"},

{IRQ_EINT2, S3C2410_GPF(2) , S3C2410_GPF2_EINT2, 2, "KEY2"},

{IRQ_EINT8, S3C2410_GPG(0) , S3C2410_GPG0_EINT8 , 3, "KEY3"},

};

static volatile char key_values [] = {'0', '0', '0', '0', '0', '0','0', '0', '0', '0', '0', '0','0', '0', '0', '0'};

static DECLARE_WAIT_QUEUE_HEAD(button_waitq);

static volatile int ev_press = 0;

static volatile int ev_key = 0;

struct timer_list mytimer;

static void buttons_kscan_reset(int column)

{

int i;

for(i=0; i < 4; i++) {

if(i == column)

s3c2410_gpio_setpin(led_table[i], 0);

else

s3c2410_gpio_setpin(led_table[i], 1);

}

}

static void disable_irqs(void)

{

disable_irq(S3C2410_GPF5_EINT5);

disable_irq(S3C2410_GPF3_EINT3);

disable_irq(S3C2410_GPF2_EINT2);

disable_irq(S3C2410_GPG0_EINT8);

}

static void enable_irqs(void)

{

enable_irq(S3C2410_GPF5_EINT5);

enable_irq(S3C2410_GPF3_EINT3);

enable_irq(S3C2410_GPF2_EINT2);

enable_irq(S3C2410_GPG0_EINT8);

}

static int buttons_scan(void)

{

int i,j,k=0;

int column = 0;

int row = 0;

// printk("11111111111111111111111111111111111111/n");

disable_irqs();

for (i = 0; i < 4; i++) { //列线置低

s3c2410_gpio_cfgpin(led_table[i], S3C2410_GPIO_OUTPUT);

s3c2410_gpio_pullup(led_table[i], 1);

s3c2410_gpio_setpin(led_table[i], 0);

}

for (i = 0; i < 4; i++) {

s3c2410_gpio_cfgpin(button_irqs[i].pin, S3C2410_GPIO_INPUT);

s3c2410_gpio_pullup(button_irqs[i].pin,0);

}

for ( j = 0; j < 4; j++)

{

if(s3c2410_gpio_getpin(button_irqs[j].pin)==0 )

{

column=j;

break;

}

}

if(j<4)

{

for ( j = 0; j < 4; j++)

{

buttons_kscan_reset(j);

ndelay(100);

if(s3c2410_gpio_getpin(button_irqs[column].pin)==0)

{

row=j;

break;

}

}

k = column * 4 + row;

ev_key=k;

key_values[k]= '0'+ 1;

}

for (i = 0; i < 4; i++) { //列线置低

s3c2410_gpio_cfgpin(led_table[i], S3C2410_GPIO_OUTPUT);

s3c2410_gpio_pullup(led_table[i],1);

s3c2410_gpio_setpin(led_table[i], 0);

}

for (i = 0; i < 4; i++) {

s3c2410_gpio_cfgpin(button_irqs[i].pin, S3C2410_GPIO_SFN2);

// s3c2410_gpio_pullup(button_irqs[i].pin,0);

}

ev_press = 1;

del_timer(&mytimer);

wake_up_interruptible(&button_waitq);

enable_irqs();

return 0;

}

void set_timer(void)

{

init_timer(&mytimer);

mytimer.expires = jiffies+10;

mytimer.function = buttons_scan;

add_timer(&mytimer);

}

static irqreturn_t buttons_interrupt(int irq, void *dev_id)

{

struct button_irq_desc *button_irqs = (struct button_irq_desc *)dev_id;

int down;

disable_irqs();

// udelay(0);

down = !s3c2410_gpio_getpin(button_irqs->pin);

/*

if (down != (key_values[button_irqs->number] & 1)) { // Changed

key_values[button_irqs->number] = '0' + down;

ev_press = 1;

wake_up_interruptible(&button_waitq);

}

*/

// printk("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa %d/n",down);

if(down)

{

set_timer();

}

enable_irqs();

return IRQ_RETVAL(IRQ_HANDLED);

}

static int s3c24xx_buttons_open(struct inode *inode, struct file *file)

{

int i;

int err = 0;

for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++) {

if (button_irqs[i].irq < 0) {

continue;

}

err = request_irq(button_irqs[i].irq, buttons_interrupt, IRQ_TYPE_EDGE_BOTH,

button_irqs[i].name, (void *)&button_irqs[i]);

set_timer();

if (err)

break;

}

if (err) {

i--;

for (; i >= 0; i--) {

if (button_irqs[i].irq < 0) {

continue;

}

disable_irq(button_irqs[i].irq);

free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);

}

return -EBUSY;

}

ev_press = 1;

return 0;

}

static int s3c24xx_buttons_close(struct inode *inode, struct file *file)

{

int i;

for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++) {

if (button_irqs[i].irq < 0) {

continue;

}

free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);

}

return 0;

}

static int s3c24xx_buttons_read(struct file *filp, char __user *buff, size_t count, loff_t *offp)

{

unsigned long err;

if (!ev_press) {

if (filp->f_flags & O_NONBLOCK)

return -EAGAIN;

else

wait_event_interruptible(button_waitq, ev_press);

}

ev_press = 0;

err = copy_to_user(buff, (const void *)key_values, min(sizeof(key_values), count));

key_values [ev_key] = '0';

return err ? -EFAULT : min(sizeof(key_values), count);

}

static unsigned int s3c24xx_buttons_poll( struct file *file, struct poll_table_struct *wait)

{

unsigned int mask = 0;

poll_wait(file, &button_waitq, wait);

if (ev_press)

mask |= POLLIN | POLLRDNORM;

return mask;

}

static struct file_operations dev_fops = {

.owner = THIS_MODULE,

.open = s3c24xx_buttons_open,

.release = s3c24xx_buttons_close,

.read = s3c24xx_buttons_read,

.poll = s3c24xx_buttons_poll,

};

static struct miscdevice misc = {

.minor = MISC_DYNAMIC_MINOR,

.name = DEVICE_NAME,

.fops = &dev_fops,

};

static int __init dev_init(void)

{

int ret;

ret = misc_register(&misc);

printk (DEVICE_NAME"/tinitialized/n");

return ret;

}

static void __exit dev_exit(void)

{

misc_deregister(&misc);

}

module_init(dev_init);

module_exit(dev_exit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("FriendlyARM Inc.");