micro2440 按键驱动程序

my_buttons.c文件：

#include <linux/fs.h>#include <linux/poll.h>#include <linux/irq.h>#include <linux/interrupt.h>#include <mach/regs-gpio.h>#include <mach/hardware.h>#include <linux/miscdevice.h>#define DEVICE_NAME     "mybuttons"struct button_irq_desc {    int irq;    int pin;    int pin_setting;    int number;    char *name;};#if !defined (CONFIG_QQ2440_BUTTONS)static struct button_irq_desc button_irqs [] = {    {IRQ_EINT8 , S3C2410_GPG0 ,  S3C2410_GPG0_EINT8  , 0, "KEY0"},    {IRQ_EINT11, S3C2410_GPG3 ,  S3C2410_GPG3_EINT11 , 1, "KEY1"},    {IRQ_EINT13, S3C2410_GPG5 ,  S3C2410_GPG5_EINT13 , 2, "KEY2"},    {IRQ_EINT14, S3C2410_GPG6 ,  S3C2410_GPG6_EINT14 , 3, "KEY3"},    {IRQ_EINT15, S3C2410_GPG7 ,  S3C2410_GPG7_EINT15 , 4, "KEY4"},    {IRQ_EINT19, S3C2410_GPG11,  S3C2410_GPG11_EINT19, 5, "KEY5"},};#else /* means QQ */static struct button_irq_desc button_irqs [] = {    {IRQ_EINT19, S3C2410_GPG11, S3C2410_GPG11_EINT19, 0, "KEY0"},    {IRQ_EINT11, S3C2410_GPG3,  S3C2410_GPG3_EINT11,  1, "KEY1"},    {IRQ_EINT2,  S3C2410_GPF2,  S3C2410_GPF2_EINT2,   2, "KEY2"},    {IRQ_EINT0,  S3C2410_GPF0,  S3C2410_GPF0_EINT0,   3, "KEY3"},    {       -1,            -1,                 -1,    4, "KEY4"},    {       -1,            -1,                 -1,    5, "KEY5"},};#endifstatic volatile char key_values [] = {'0', '0', '0', '0', '0', '0'};static DECLARE_WAIT_QUEUE_HEAD(button_waitq);static volatile int ev_press = 0;static irqreturn_t buttons_interrupt(int irq, void *dev_id){    struct button_irq_desc *button_irqs = (struct button_irq_desc *)dev_id;    int down;    // udelay(0);    down = !s3c2410_gpio_getpin(button_irqs->pin);    if (down != (key_values[button_irqs->number] & 1)) { // Changedkey_values[button_irqs->number] = '0' + down;        ev_press = 1;        wake_up_interruptible(&button_waitq);    }        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]);        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));    return err ? -EFAULT : min(sizeof(key_values), count);}static struct file_operations dev_fops = {    .owner   =   THIS_MODULE,    .open    =   s3c24xx_buttons_open,    .release =   s3c24xx_buttons_close,     .read    =   s3c24xx_buttons_read,};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.");

buttons_test.c文件：

#include <stdio.h>#include <stdlib.h>int main(void){int buttons_fd;char buttons[6] = {'0', '0', '0', '0', '0', '0'};buttons_fd = open("/dev/mybuttons", 0);if (buttons_fd < 0) {perror("open device buttons");exit(1);}for (;;) {char current_buttons[6];int count_of_changed_key;int i;if (read(buttons_fd, current_buttons, sizeof current_buttons) != sizeof current_buttons) {perror("read buttons:");exit(1);}for (i = 0, count_of_changed_key = 0; i < sizeof buttons / sizeof buttons[0]; i++) {if (buttons[i] != current_buttons[i]) {buttons[i] = current_buttons[i];printf("%skey %d is %s", count_of_changed_key? ", ": "", i+1, buttons[i] == '0' ? "up" : "down");count_of_changed_key++;}}if (count_of_changed_key) {printf("\n");}}close(buttons_fd);return 0;}

实验步骤跟led驱动的编写步骤是一样的，具体可参考led驱动