- 论坛徽章:
- 0
|
本帖最后由 hoursjl 于 2014-05-26 14:58 编辑
回复 2# arm-linux-gcc
确实没用你说的函数。 我刚接触嵌入式linux驱动，有没有什么资料推荐我看一下啊？ 谢谢！
/*
* blink.c - Create an input/output character device
*/
#include <linux/kernel.h> /* We're doing kernel work */
#include <linux/module.h> /* Specifically, a module */
#include <linux/fs.h>
#include <asm/uaccess.h> /* for get_user and put_user */
#include <asm/io.h>
#include "blink.h"
#define SUCCESS 0
#define DEVICE_NAME "/dev/blink_Dev"
#define BLINK_CTRL_REG 0x7C600000
static void *mmio;
static int major_num;
/*
* Is the device open right now? Used to prevent
* concurent access into the same device
*/
static int Device_Open = 0;
static void set_blink_ctrl(void)
{
printk("KERNEL PRINT : set_blink_ctrl \n\r");
*(unsigned int *)mmio = 0x1;
}
static void reset_blink_ctrl(void)
{
printk("KERNEL PRINT : reset_blink_ctrl \n\r");
*(unsigned int *)mmio = 0x0;
}
/*
* This is called whenever a process attempts to open the device file
*/
static int device_open(struct inode *inode, struct file *file)
{
#ifdef DEBUG
printk(KERN_INFO "device_open(%p)\n", file);
#endif
/*
* We don't want to talk to two processes at the same time
*/
if (Device_Open)
return -EBUSY;
Device_Open++;
/*
* Initialize the message
*/
// Message_Ptr = Message;
try_module_get(THIS_MODULE);
return SUCCESS;
}
static int device_release(struct inode *inode, struct file *file)
{
#ifdef DEBUG
printk(KERN_INFO "device_release(%p,%p)\n", inode, file);
#endif
/*
* We're now ready for our next caller
*/
Device_Open--;
module_put(THIS_MODULE);
return SUCCESS;
}
/*
* This function is called whenever a process which has already opened the
* device file attempts to read from it.
*/
static ssize_t device_read( struct file *file, /* see include/linux/fs.h */
char __user * buffer, /* buffer to be filled with data */
size_t length, /* length of the buffer */
loff_t * offset)
{
return SUCCESS;
}
/*
* This function is called when somebody tries to
* write into our device file.
*/
static ssize_t device_write(struct file *file,
const char __user * buffer,
size_t length,
loff_t * offset)
{
return SUCCESS;
}
/*
* This function is called whenever a process tries to do an ioctl on our
* device file. We get two extra parameters (additional to the inode and file
* structures, which all device functions get): the number of the ioctl called
* and the parameter given to the ioctl function.
*
* If the ioctl is write or read/write (meaning output is returned to the
* calling process), the ioctl call returns the output of this function.
*
*/
int device_ioctl( struct file *file, /* ditto */
unsigned int ioctl_num, /* number and param for ioctl */
unsigned long ioctl_param)
{
// int i;
char *temp;
// char ch;
/*
* Switch according to the ioctl called
*/
switch (ioctl_num)
{
case IOCTL_ON_LED:
temp = (char *)ioctl_param;
set_blink_ctrl();
break;
case IOCTL_STOP_LED:
temp = (char *)ioctl_param;
reset_blink_ctrl();
break;
}
return SUCCESS;
}
/* Module Declarations */
/*
* This structure will hold the functions to be called
* when a process does something to the device we
* created. Since a pointer to this structure is kept in
* the devices table, it can't be local to
* init_module. NULL is for unimplemented functions.
*/
struct file_operations Fops = {
.read = device_read,
.write = device_write,
.unlocked_ioctl = device_ioctl,
.open = device_open,
.release = device_release, /*close */ };
/*
* Initialize the module - Register the character device
*/
int init_module()
{
int ret_val;
/*
* Register the character device (atleast try)
*/
major_num = register_chrdev(0,DEVICE_NAME, &Fops);
/*
* Negative values signify an error
*/
if (major_num < 0)
{
printk(KERN_ALERT "%s failed with %d\n","Sorry, registering the character device ", ret_val);
return ret_val;
}
printk(KERN_INFO "%s The major device number is %d.\n",
"Registeration is a success", major_num);
printk(KERN_INFO "If you want to talk to the device driver,\n");
printk(KERN_INFO "Than create a device file by following command. \n");
printk(KERN_INFO "mknod %s c %d 0\n", DEVICE_FILE_NAME, major_num);
printk(KERN_INFO "The device file name is important, because\n");
printk(KERN_INFO "the ioctl program assumes that's the\n");
printk(KERN_INFO "file you'll use.\n");
mmio = ioremap(BLINK_CTRL_REG,0x100);
return 0;
}
/*
* Cleanup - unregister the appropriate file from /proc
*/
void cleanup_module()
{
/*
* Unregister the device
*/
iounmap(mmio);
unregister_chrdev(major_num,DEVICE_NAME);
}
|
|
免费注册
发表于 2014-05-24 11:16
