matrix4-buttons.c

matrix开发版的键盘驱动程序

#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>

#define DEVICE_NAME	"buttons"
#define BUTTON_MAJOR 232
#define IRQ_BUTTONS IRQ_EINT7


static int count = 0;

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

static DECLARE_WAIT_QUEUE_HEAD(buttons_wait);

static int waitting_down = 1;
static void buttons_irq(int irq, void *dev_id, struct pt_regs *reg)
{
	int key_no;
	unsigned char data;
	if (waitting_down) {
		key_no = 0;
		GPFCON = (GPFCON & 0x3F03) | 4;
		udelay(300);
		data = GPFDAT;
		if ((data & 0x80) == 0) {
			if (data & 0x04) {
				key_no = 2;
			} else if (data & 0x08) {
				key_no = 3;
			} else {
				key_no = 1;
			}
			goto found;
		}
		GPFCON = (GPFCON & 0x3F03) | 0x10;
		udelay(300);
		data = GPFDAT;
		if ((data & 0x80) == 0) {
			if (data & 0x02) {
				key_no = 4;
			} else if (data & 0x08) {
				key_no = 6;
			} else {
				key_no = 5;
			}
			goto found;
		}
		GPFCON = (GPFCON & 0x3F03) | 0x40;
		udelay(300);
		data = GPFDAT;
		if ((data & 0x80) == 0) {
			if (data & 0x02) {
				key_no = 7;
			} else if (data & 0x04) {
				key_no = 8;
			}
		}
	found:
		GPFCON = (GPFCON & 0x3F03) | (2 << 14) | (1 << 6) | (1 << 4) | (1 << 2);
		if (key_no) {
			ready = 1;
			key_value = key_no;
			//printk("%d: key%d pressed\n", count++, key_no);
			wake_up_interruptible(&buttons_wait);
			EXTINT0 = (EXTINT0 & ~(7U << 28)) | (1U << 28);
			waitting_down = 0;
		}
	} else {
		GPFCON = GPFCON & 0x3FFF;
		udelay(300);
		data = GPFDAT;
		GPFCON |= (2 << 14);
		if ((data & 0x80)) {
			ready = 1;
			key_value = -1;
			wake_up_interruptible(&buttons_wait);
			//printk("%d: released\n", count++);
			waitting_down = 1;
			EXTINT0 &= ~(7U << 28);
		}
	}
}

static void buttons_io_port_init(void)
{
	set_gpio_ctrl(GPIO_F1 | GPIO_PULLUP_DIS | GPIO_MODE_OUT);
	set_gpio_ctrl(GPIO_F2 | GPIO_PULLUP_DIS | GPIO_MODE_OUT);
	set_gpio_ctrl(GPIO_F3 | GPIO_PULLUP_DIS | GPIO_MODE_OUT);
	write_gpio_bit(GPIO_F1, 1);
	write_gpio_bit(GPIO_F2, 1);
	write_gpio_bit(GPIO_F3, 1);
	
}

static int matrix4_buttons_read(struct file * file, char * buffer, size_t count, loff_t *ppos)
{
        if (!ready)
                return -EAGAIN;
        if (count != sizeof key_value)
                return -EINVAL;

        copy_to_user(buffer, &key_value, sizeof key_value);
        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);
        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();
	
	set_external_irq(IRQ_BUTTONS, EXT_LOWLEVEL, GPIO_PULLUP_DIS);
	ret = request_irq(IRQ_BUTTONS, &buttons_irq, SA_INTERRUPT, DEVICE_NAME, &buttons_irq);
	if (ret) {
		unregister_chrdev(BUTTON_MAJOR, DEVICE_NAME);
		printk(DEVICE_NAME " can't request irq %d\n", IRQ_BUTTONS);
		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_irq(IRQ_BUTTONS, buttons_irq);
	unregister_chrdev(BUTTON_MAJOR, DEVICE_NAME);
}

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