Linux 驅動——Button驅動1
button_drv.c驅動文件：
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <asm/io.h> //包含iomap函數iounmap函數
#include <asm/uaccess.h> //包含copy_from_user函數
#include <linux/device.h> //包含class類相關的處理函數
#include <linux/fs.h> //包含
#define DRIVER_NAME "button_drv"
#define DEVICE_NAME "button_dev"
int major;
static struct class *buttondrv_class;
static struct class_device *buttondrv_class_dev;
volatile unsigned long *gpfcon = NULL;
volatile unsigned long *gpfdat = NULL;
volatile unsigned long *gpgcon = NULL;
volatile unsigned long *gpgdat = NULL;
static int button_drv_open(struct inode *inode, struct file *file)
{
*gpfcon &= ~((0x3<<(0*2)) | (0x3<<(2*2)));
*gpgcon &= ~((0x3<<(3*2)) | (0x3<<(11*2)));
return 0;
}
static int button_drv_read(struct file * file, char __user * userbuf, size_t count, loff_t * off)
{
int ret;
unsigned char keyVal[4];
unsigned long keyVals;
if(count!=sizeof(keyVal))
{
printk("button_drv_read error 1 \n");
}
keyVals = *gpfdat;
keyVal[0] = ((keyVals>>0) & 1);
keyVal[1] = ((keyVals>>2) & 1);
keyVals = *gpgdat;
keyVal[2] = ((keyVals>>3) & 1);
keyVal[3] = ((keyVals>>11) & 1);
ret = copy_to_user(userbuf, keyVal, sizeof(keyVal));
if(ret<0)
{
printk("button_drv_read error 2 \n");
}
return sizeof(keyVal);
}
static struct file_operations button_drv_fops = {
.owner = THIS_MODULE,
.open = button_drv_open,
.read = button_drv_read,
};
static int button_drv_init(void)
{
major = register_chrdev(0, DRIVER_NAME, &button_drv_fops);
buttondrv_class = class_create(THIS_MODULE, DEVICE_NAME);
buttondrv_class_dev = class_device_create(buttondrv_class, NULL, MKDEV(major, 0), NULL, DEVICE_NAME);
gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);
gpfdat = gpfcon + 1;
gpgcon = (volatile unsigned long *)ioremap(0x56000060, 16);
gpgdat = gpgcon + 1;
return 0;
}
static void button_drv_exit(void)
{
unregister_chrdev(major, DRIVER_NAME);
class_device_unregister(buttondrv_class_dev);
class_destroy(buttondrv_class);
iounmap(gpfcon);
iounmap(gpgcon);
}
module_init(button_drv_init);
module_exit(button_drv_exit);
MODULE_LICENSE("GPL");
Makefile文件：
obj-m += button_drv.o
KERN_DIR = /work/system/linux-2.6.22.6
all:
make -C $(KERN_DIR) M=`pwd` modules
clean:
rm -rf *.o *.ko *.order *.symvers *.mod.c
button_app.c文件:
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
int main(int argc, char **argv)
{
int fd;
int val;
char *filename;
unsigned char keyVal[4];
filename = argv[1];
fd = open(filename, O_RDWR);
if(fd<0)
{
printf("can not open \n");
}
while(1)
{
read(fd, keyVal, sizeof(keyVal));
if(!keyVal[0] || !keyVal[1] || !keyVal[2] || !keyVal[3])
{
printf("key pressed %d %d %d %d \n", keyVal[0], keyVal[1], keyVal[2], keyVal[3]);
}
}
return 0;
}
編譯生成button_drv.ko文件和button_app文件，運行：./button_app /dev/button_dev
Linux 驅動——Button驅動1