my_bt.c

一个简单明了的用按键点亮LED的驱动(SBC2410),非常适合驱动入门

//#include <linux/config.h>

#include <linux/module.h> 
#include <linux/kernel.h> 
#include <linux/init.h> 
#include <linux/irq.h> 
 
#include <linux/miscdevice.h> 
#include <linux/sched.h> 
#include <linux/delay.h> 
#include <linux/poll.h> 
#include <linux/spinlock.h> 
#include <linux/delay.h> 
#include <linux/interrupt.h>

#include <asm/hardware.h> 
#include <asm/arch/regs-gpio.h> 
#include <asm/arch/irqs.h> 
#include <linux/device.h> 
#include <linux/types.h> 
#include <linux/cdev.h> 
#include <linux/errno.h> 
#include <asm/uaccess.h> 

#define DEVICE_NAME "button"
#define MAX_KEY_BUF 16
#define KEY_NUM 4

static int button_major = 232;
typedef struct
{
	unsigned int key_status[KEY_NUM];
	//unsigned char buf[MAX_KEY_BUF];
	//unsigned int head, tail;
	//wait_queue_head_t wq;
	struct cdev cdev;   
}button_dev;

static button_dev *button_p; 

static struct led_info
{
	unsigned long gpio;
	unsigned long gpio_status;
}led_table[4] = 
{
	{S3C2410_GPB7,S3C2410_GPB7_OUTP},
	{S3C2410_GPB8,S3C2410_GPB8_OUTP},
	{S3C2410_GPB9,S3C2410_GPB9_OUTP},
	{S3C2410_GPB10,S3C2410_GPB10_OUTP},
};

static struct key_info
{
	int irq_no;
	unsigned int gpio_port;
	int key_no;
}key_info_table[4] =
{
  {	IRQ_EINT1, S3C2410_GPF1, 1},
  {	IRQ_EINT2, S3C2410_GPF2, 2},
  {	IRQ_EINT3, S3C2410_GPF3, 3},
  {	IRQ_EINT7, S3C2410_GPF7, 4},	
};

static void buttons_irq(int irq, void *dev_id, struct pt_regs *reg)
{
	struct key_info *k;
	int i,j = (int)dev_id;
	printk("int %d received\n", j);
	unsigned int value;
	int found = 0;
	for (i = 0; i < sizeof key_info_table / sizeof key_info_table[1]; i++)
	{
	   k = key_info_table + i;
	   if (k->irq_no == irq)
		 {
		    found = 1;
		    break;
		 }
	}
	if (!found)
	{
	   printk("bad irq %d in button\n", irq);
	   return;
	}
  printk("interrupt %d received!\n", i);
  value = s3c2410_gpio_getpin(led_table[i].gpio);
	if(value)
		s3c2410_gpio_setpin(led_table[i].gpio,0);
	else
		s3c2410_gpio_setpin(led_table[i].gpio,1);
}

static int request_irqs(void)
{
  struct key_info *k;
  int i;
  for (i = 0; i < sizeof key_info_table / sizeof key_info_table[1]; i++)
	{
     k = key_info_table + i;
     //set_external_irq(k->irq_no, EXT_BOTH_EDGES, GPIO_PULLUP_DIS);
		 set_irq_type(k->irq_no, IRQT_BOTHEDGE);
     if (request_irq(k->irq_no, &buttons_irq, SA_INTERRUPT, DEVICE_NAME,
				i))
		 {
        return -1;
     }
  }
	printk("irq request successfully!\n");
  return 0;
}

static void free_irqs(void)
{
	struct key_info *k;
	int i;
	for (i = 0; i < sizeof key_info_table / sizeof key_info_table[1]; i++)
	{
	  k = key_info_table + i;
	  free_irq(k->irq_no, buttons_irq);
	}
}


static void button_setup(button_dev *dev, int index)
{
	int err, devno = MKDEV(button_major, index);
	dev->cdev.owner = THIS_MODULE;
	err = cdev_add(&dev->cdev, devno, 1);
	if(err)
	{
		printk(KERN_NOTICE"Error %d adding button", err);
	}
}

static int button_init(void)
{
	int ret,i;
	dev_t devno = MKDEV(button_major,0);
	ret = register_chrdev_region(devno, 1, "button");
	if(ret)
		return ret;
	button_p = kmalloc(sizeof(button_dev), GFP_KERNEL);
	if(!button_p)
	{
		ret = -ENOMEM;
		goto fail;
	}
  memset(button_p, 0, sizeof(button_dev));
  button_setup(button_p, 0);
	for(i=0;i<4;i++)
	{
		s3c2410_gpio_cfgpin(led_table[i].gpio, led_table[i].gpio_status);
		s3c2410_gpio_setpin(led_table[i].gpio, 1);
		printk("led%d initialized!\n",i+1);
	}
  ret = request_irqs();
	if(ret)
	{
		printk(DEVICE_NAME " can't request irqs\n");
		goto fail;
	}
	printk("int request ok!\n");
	return 0;
fail:
	unregister_chrdev_region(devno, 1);
	return ret;
}

static void button_exit(void)
{
	cdev_del(&button_p->cdev);
	kfree(button_p);
	unregister_chrdev_region(MKDEV(button_major,0), 1);	
	free_irqs();
}

MODULE_AUTHOR("jimmy");
MODULE_LICENSE("Daul BSD/GPL");

module_param(button_major, int, S_IRUGO);
module_init(button_init);
module_exit(button_exit);