arm6410按键驱动程序

arm6410按键驱动程序

通过查询的方法获取按键值
驱动程序  botton_drive.c

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/delay.h>

#include <asm/uaccess.h>

#include <asm/irq.h>

#include <asm/io.h>

#include <linux/device.h>

//#include <asm/arch/regs-gpio.h>

//#include <asm/hardware.h>

static struct class *seconddrv_class;

static struct class_device*seconddrv_class_dev;

volatile unsigned long *gpmcon = NULL;

volatile unsigned long *gpmdat = NULL;

volatile unsigned long *gpncon = NULL;

volatile unsigned long *gpndat = NULL;

static int second_drv_open(struct inode *inode, struct file *file)

{

//printk("second_drv_open\n");

/* 配置GPm0,1,2,3为输出 */

*gpmcon &= ~((0xf<<(4*0)) | (0xf<<(4*1)) | (0xf<<(4*2)) | (0xf<<(4*3)));

*gpmcon |=  ((0x1<<(4*0)) | (0x1<<(4*1)) | (0x1<<(4*2)) | (0x1<<(4*3)));

/* 配置GPn0,1,2,3,4,5为输入 */

*gpncon &= ~((0x3<<(2*0)) | (0x3<<(2*1)) | (0x3<<(2*2)) | (0x3<<(2*3)) | (0x3<<(2*4)) | (0x3<<(2*5)));

//*gpncon |=  ((0xf<<(4*0)) | (0xf<<(4*1)) | (0xf<<(4*2)) | (0xf<<(4*3)) | (0xf<<(4*4)) | (0xf<<(4*5)));

return 0;

}

static ssize_t second_drv_read(struct file *file, const char __user *buf, size_t size, loff_t * ppos)

{

unsigned char KEY_val[6];

if(size != sizeof(KEY_val))

return -EINVAL;

int regval;

regval = *gpndat;

/* 读出个个引脚的状态 */

KEY_val[0] = (regval & 1<<0) ? 1:0;

KEY_val[1] = (regval & 1<<1) ? 1:0;

KEY_val[2] = (regval & 1<<2) ? 1:0;

KEY_val[3] = (regval & 1<<3) ? 1:0;

KEY_val[4] = (regval & 1<<4) ? 1:0;

KEY_val[5] = (regval & 1<<5) ? 1:0;

/* 传递给用户 */

copy_to_user(buf, KEY_val, sizeof(KEY_val));

return sizeof(KEY_val);

}

static struct file_operations second_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   =   second_drv_open,     

.read= second_drv_read,   

};

int major;

static int second_drv_init(void)

{

//printk(KERN_ERR "second_drv_init\n");

major = register_chrdev(0, "secondt_drv", &second_drv_fops); // 注册, 告诉内核

seconddrv_class = class_create(THIS_MODULE, "seconddrv");

seconddrv_class_dev = device_create(seconddrv_class, NULL, MKDEV(major, 0), NULL, "bottons"); /* /dev/bottons */

gpmcon = (volatile unsigned long *)ioremap(0x7F008820, 16);

gpmdat = gpmcon + 1;

gpncon = (volatile unsigned long *)ioremap(0x7F008830, 16);

gpndat = gpncon + 1;

return 0;

}

static void second_drv_exit(void)

{

//printk(KERN_ERR "second_drv_exit\n");

unregister_chrdev(major, "second_drv"); // 卸载

device_unregister(seconddrv_class_dev);

class_destroy(seconddrv_class);

iounmap(gpmcon);

iounmap(gpncon);

}

module_init(second_drv_init);

module_exit(second_drv_exit);

MODULE_LICENSE("GPL");

测试程序botton_test.c

 #include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <stdio.h>

/* botton test

  * 

  */

int main(int argc, char **argv)

{

int fd;

int cnt = 0;

unsigned char key_vals[6];

fd = open("/dev/bottons", O_RDWR);

if (fd < 0)

{

printf("can't open!\n");

}

while (1)

{

read(fd, key_vals, sizeof(key_vals));

if (!key_vals[0] || !key_vals[1] || !key_vals[2] || !key_vals[3] || !key_vals[4] || !key_vals[5])

{

printf("%d key pressed %d %d %d %d %d %d\n", cnt++, key_vals[0], key_vals[1], key_vals[2], 

key_vals[3], key_vals[4], key_vals[5]);

}

}

return 0;

}

加载驱动 

测试
 
当按下一个按键

有好几百个这样的输出 原因是没有加上去抖程序
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一个按键程序占用了 99.6% 的CPU 太疯狂了 原因是通过查询的方式获取按键值  程序是一个死循环 
 
下一步通过中断的方式获取按键值
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