S3C2416 按键驱动，s3c2416按键驱动

文章由LinuxBoy分享于2019-03-27 08:03:53热评（155）

S3C2416 按键驱动，s3c2416按键驱动

基于韦东山的驱动修改的，由于内核版本不一样，包含到头文件有所变化，内核API函数也有所改变。

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/io.h> 
#include <mach/regs-gpio.h>  //修改
#include <mach/hardware.h>  //修改
#include <linux/device.h>  //增加
#include <mach/irqs.h>
#include <linux/interrupt.h>
#include <mach/gpio-fns.h>  //修改
#include <linux/sched.h>  //增加

static struct class *buttondrv_class;
static struct class_device *buttondrv_class_dev;

volatile unsigned long *gpfcon;
volatile unsigned long *gpfdat;


static DECLARE_WAIT_QUEUE_HEAD(button_waitq);

/* 中断事件标志, 中断服务程序将它置1，button_drv_read将它清0 */
//static volatile int ev_press = 0;
int err = 0;

struct pin_desc{
	unsigned int pin;
	unsigned int key_val;
};


/* 键值: 按下时, 0x01 */
/* 键值: 松开时, 0x81 */
static unsigned char key_val;

struct pin_desc pins_desc[] = {{S3C2410_GPF(5), 0x01},};


/*
  * 确定按键值
  */
static irqreturn_t buttons_irq(int irq, void *dev_id)
{
	struct pin_desc * pindesc = (struct pin_desc *)dev_id;
	unsigned int pinval;
	
	pinval = s3c2410_gpio_getpin(pindesc->pin);

	if (pinval)
	{
		/* 松开 */
		key_val = 0x80 | pindesc->key_val;
	}
	else
	{
		/* 按下 */
		key_val = pindesc->key_val;
	}

 //   ev_press = 1;                  /* 表示中断发生了 */
 //   wake_up_interruptible(&button_waitq);   /* 唤醒休眠的进程 */

	
	return IRQ_RETVAL(IRQ_HANDLED);
}

static int button_drv_open(struct inode *inode, struct file *file)
{
	/* 配置GPF5为输入引脚 */
	err = request_irq(IRQ_EINT5,  buttons_irq, IRQF_TRIGGER_HIGH, "S2", &pins_desc[0]);
	if(err < 0)
	{
		printk("fail to request_irq\n");
	}

	return 0;
}

ssize_t button_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
	if (size != 1)
		return -EINVAL;

	/* 如果没有按键动作, 休眠 */
//	wait_event_interruptible(button_waitq, ev_press);

	/* 如果有按键动作, 返回键值 */
	err = copy_to_user(buf, &key_val, 1);
	if(err < 0)
	{
		printk("fail to copy_to_user\n");
	}
	//ev_press = 0;
	
	return 1;
}


int button_drv_close(struct inode *inode, struct file *file)
{
	free_irq(IRQ_EINT5, &pins_desc[0]);
	return 0;
}


static struct file_operations sencod_drv_fops = {
    .owner   =  THIS_MODULE,    /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */
    .open    =  button_drv_open,     
    .read    =	button_drv_read,	   
    .release =  button_drv_close,	   
};


int major;
static int button_drv_init(void)
{
	major = register_chrdev(0, "button_drv", &sencod_drv_fops);

	buttondrv_class = class_create(THIS_MODULE, "button_drv");

	buttondrv_class_dev = device_create(buttondrv_class, NULL, MKDEV(major, 0), NULL, "buttons"); /* /dev/buttons */

	gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);
	gpfdat = gpfcon + 1;

	return 0;
}

static void button_drv_exit(void)
{
	unregister_chrdev(major, "button_drv");
	device_unregister(buttondrv_class_dev);
	class_destroy(buttondrv_class);
	iounmap(gpfcon);
	return 0;
}


module_init(button_drv_init);

module_exit(button_drv_exit);

MODULE_LICENSE("GPL");

<pre name="code" class="cpp">S3C2410_GPF5修改为 S3C2410_GPF(5)  具体可以参阅kernel/Documentation/arm/Samsung-S3C24XX/GPIO.txt

request_irq 第三个参数，中断触发方式到宏有所改变改为 kernel/include/linux/interrupt.h中

/*
 * These correspond to the IORESOURCE_IRQ_* defines in
 * linux/ioport.h to select the interrupt line behaviour.  When
 * requesting an interrupt without specifying a IRQF_TRIGGER, the
 * setting should be assumed to be "as already configured", which
 * may be as per machine or firmware initialisation.
 */
#define IRQF_TRIGGER_NONE	0x00000000
#define IRQF_TRIGGER_RISING	0x00000001   //上升沿触发
#define IRQF_TRIGGER_FALLING	0x00000002
#define IRQF_TRIGGER_HIGH	0x00000004    //高点平触发
#define IRQF_TRIGGER_LOW	0x00000008
#define IRQF_TRIGGER_MASK	(IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW | \
				 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
#define IRQF_TRIGGER_PROBE	0x00000010

测试程序：

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>

/* thirddrvtest 
  */
int main(int argc, char **argv)
{
	int fd;
	unsigned char key_val;
	
	fd = open("/dev/buttons", O_RDWR);
	if (fd < 0)
	{
		printf("can't open!\n");
	}

	while (1)
	{
		read(fd, &key_val, 1);   //读取内核空间中的key_val值
		//printf("key_val = 0x%x\n", key_val);
		sleep(1);
		if( key_val == 0x01 )
		{
			printf("power off!\n");
		}
	}
	
	return 0;
}

下载到板子：

Linux操作

① # exec5</dev/key  打开该中断设备将 /dev/key 定位到 5
   # exec5<&-        关闭
② # cat /proc/interrupts  查看中断设备

卸载驱动：

/ # lsmod
button_drv 1679 2 - Live 0xbf000000

/ # rmmod button_drv
rmmod: remove 'button_drv': Resource temporarily unavailable

/ # ps
PID   USER     TIME   COMMAND
    1 root       0:01 {linuxrc} init
1060 root       0:00 [flush-ubifs_0_0]
1066 root       0:00 ./buttondrvtest

/ # kill -9 1066
[1]+ Killed ./buttondrvtest

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S3C2416 按键驱动，s3c2416按键驱动