Linux ioctl 从应用到驱动
驱动
将示例代码中n76e003_driver复制到linux/drivers/misc目录下，修改相关Kconfig与Makefile文件
- 头文件中定义ioctl命令
// ioctl cmd
#define N76E003_IOC_MAGIC 'k'
#define N76E003_IOC_HEARTBEAT _IO(N76E003_IOC_MAGIC, 1)
#define N76E003_IOC_SET_UPTIME _IOW(N76E003_IOC_MAGIC, 2, int)
#define N76E003_IOC_MAXNR 2
struct n76e003_data {
struct i2c_client *client;
struct miscdevice n76e003_device;
};
- 实现ioctl函数
static int n76e003_dev_open(struct inode *inode, struct file *filp)
{
int ret = 0;
struct n76e003_data *n76e003 = container_of(filp->private_data,
struct n76e003_data,
n76e003_device);
filp->private_data = n76e003;
dev_info(&n76e003->client->dev,
"device node major=%d, minor=%d\n", imajor(inode), iminor(inode));
return ret;
}
static long n76e003_dev_ioctl(struct file *pfile,
unsigned int cmd, unsigned long arg)
{
int ret = 0;
int data = 0;
struct n76e003_data *n76e003 = pfile->private_data;
if (_IOC_TYPE(cmd) != N76E003_IOC_MAGIC)
return -EINVAL;
if (_IOC_NR(cmd) > N76E003_IOC_MAXNR)
return -EINVAL;
if (_IOC_DIR(cmd) & _IOC_READ)
ret = !access_ok(VERIFY_WRITE, (void *)arg, _IOC_SIZE(cmd));
else if (_IOC_DIR(cmd) & _IOC_WRITE)
ret = !access_ok(VERIFY_READ, (void *)arg, _IOC_SIZE(cmd));
if (ret)
return -EFAULT;
dev_info(&n76e003->client->dev,
"%s, (%x, %lx):\n", __func__, cmd,
arg);
switch (cmd) {
case N76E003_IOC_HEARTBEAT:
n76e003_heartbeat(n76e003->client);
break;
case N76E003_IOC_SET_UPTIME:
if (copy_from_user(&data, (int *)arg, sizeof(int))) {
dev_err(&n76e003->client->dev,
"%s, copy from user failed\n", __func__);
return -EFAULT;
}
n76e003_set_uptime(n76e003->client, data);
break;
default:
return -EINVAL;
}
return 0;
}
- 定义file_operations
static const struct file_operations n76e003_dev_fops = {
.owner = THIS_MODULE,
.open = n76e003_dev_open,
.unlocked_ioctl = n76e003_dev_ioctl
};
- 注册设备
static int n76e003_probe(struct i2c_client * client, const struct i2c_device_id * id)
{
...
n76e003->n76e003_device.minor = MISC_DYNAMIC_MINOR;
n76e003->n76e003_device.name = "n76e003";
n76e003->n76e003_device.fops = &n76e003_dev_fops;
ret = misc_register(&n76e003->n76e003_device);
if (ret) {
dev_err(&client->dev, "Failed misc_register\n");
goto exit_misc_register;
}
...
}
应用程序
如果是Android工程，将示例代码中n76e003_app复制到external目录下，并在Android根目录执行：make n76e003
#include <sys/types.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <unistd.h>
#define DEV_NAME "/dev/n76e003"
// ioctl cmd
#define N76E003_IOC_MAGIC 'k'
#define N76E003_IOC_HEARTBEAT _IO(N76E003_IOC_MAGIC, 1)
#define N76E003_IOC_SET_UPTIME _IOW(N76E003_IOC_MAGIC, 2, int)
int main(int argc, char const *argv[])
{
int ret, fd, num, arg;
fd = open(DEV_NAME, O_RDWR);
if (fd < 0) {
printf("Open device fail!\n");
return -1;
}
/*
read(fd, &num, sizeof(int));
printf("The num is: %d\n", num);
printf("Please input a number written to testdriver: \n");
scanf("%d", &num);
write(fd, &num, sizeof(int));
read(fd, &num, sizeof(int));
printf("The num is: %d\n", num);
*/
arg = 0xff;
ret = ioctl(fd, N76E003_IOC_HEARTBEAT, &arg);
if (ret < 0) {
printf("ioctl: %d\n", ret);
}
sleep(10);
arg = 0x01020304;
ret = ioctl(fd, N76E003_IOC_SET_UPTIME, &arg);
if (ret < 0) {
printf("ioctl: %d\n", ret);
}
close(fd);
return 0;
}
