mini2440 buttons的驱动-linux3.10.59

mini2440 buttons的驱动-linux3.10.59

/* linux/drivers/char/mini2440_buttons.c *Copyright (c) 2013 Feng Guoqing * * mini2440 buttons Driver * * This file is subject to the terms and conditions of the GNU General Public * License.  See the file COPYING in the main directory of this archive for * more details. **/#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>#define DEVICE_NAME "buttons"struct button_irq_desc {     int irq;     int pin;     int pin_setting;    int number;    char *name;}; static struct button_irq_desc button_irqs [] = {     {IRQ_EINT8 , S3C2410_GPG(0) , S3C2410_GPG0_EINT8 , 0, "KEY0"},     {IRQ_EINT11, S3C2410_GPG(3) , S3C2410_GPG3_EINT11 , 1, "KEY1"},     {IRQ_EINT13, S3C2410_GPG(5) , S3C2410_GPG5_EINT13 , 2, "KEY2"},     {IRQ_EINT14, S3C2410_GPG(6) , S3C2410_GPG6_EINT14 , 3, "KEY3"},     {IRQ_EINT15, S3C2410_GPG(7) , S3C2410_GPG7_EINT15 , 4, "KEY4"},     {IRQ_EINT19, S3C2410_GPG(11), S3C2410_GPG11_EINT19, 5, "KEY5"}, }; static 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;     down = !gpio_get_value(button_irqs->pin);     if (down != (key_values[button_irqs->number] & 1)) {         key_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 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.");