mini6410按键驱动程序

mini6410按键驱动程序:

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/irq.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <mach/hardware.h>
#include <linux/platform_device.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>

#include <mach/map.h>
#include <mach/regs-clock.h>
#include <mach/regs-gpio.h>

#include <plat/gpio-cfg.h>
#include <mach/gpio-bank-n.h>
#include <mach/gpio-bank-l.h>

#define DEVICE_NAME     "buttons"

struct button_irq_desc {
    int irq;
    int number;
    char *name;
};

static struct button_irq_desc button_irqs [] = {
    {IRQ_EINT( 0), 0, "KEY0"},
    {IRQ_EINT( 1), 1, "KEY1"},
    {IRQ_EINT( 2), 2, "KEY2"},
    {IRQ_EINT( 3), 3, "KEY3"},
    {IRQ_EINT( 4), 4, "KEY4"},
    {IRQ_EINT( 5), 5, "KEY5"},
    {IRQ_EINT(19), 6, "KEY6"},
    {IRQ_EINT(20), 7, "KEY7"},
};
static volatile char key_values [] = {'0', '0', '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;
        int number;
        unsigned tmp;

udelay(0);
        number = button_irqs->number;
        switch(number) {
        case 0: case 1: case 2: case 3: case 4: case 5:
                tmp = readl(S3C64XX_GPNDAT);
                down = !(tmp & (1<<number));
                break;
        case 6: case 7:
                tmp = readl(S3C64XX_GPLDAT);
                down = !(tmp & (1 << (number + 5)));
                break;
        default:
                down = 0;
        }

if (down != (key_values[number] & 1)) {
                key_values[number] = '0' + down;

ev_press = 1;
                wake_up_interruptible(&button_waitq);
        }

return IRQ_RETVAL(IRQ_HANDLED);
}

static int s3c64xx_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;
        }
        free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);
    }

return 0;
}

static int s3c64xx_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((void *)buff, (const void *)(&key_values), min(sizeof(key_values), count));

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

static unsigned int s3c64xx_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;
}