#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <mach/platform.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <linux/init.h>
#include <linux/gpio.h>
#define DEVICE_NAME "Pi_Led"
#define DRIVER_NAME "pi_led"
//class声明内核模块驱动信息,是UDEV能够自动生成/dev下相应文件
static dev_t pi_led_devno; //设备号
static struct class *pi_led_class;
static struct cdev pi_led_class_dev;
struct gpio_chip *gpiochip;
#define led_pin 4 //gpio 4
//这部分函数为内核调用后open的设备IO操作,和裸板程序一样
int open_flag=0;
static int pi_led_open(struct inode *inode, struct file *filp)
{
printk("Open led ing!\n");
if(open_flag ==0){
open_flag =1;
printk("Open led success!\n");
return 0;
}
else{
printk("Led has opened!\n");
}
return 0;
}
//这部分函数为内核调用后ioctl的设备IO操作,和裸板程序一样
static long pi_led_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
switch(cmd){
case 0:
gpiochip->set(gpiochip, led_pin, 0);
printk("Led up!\n");
break;
case 1:
gpiochip->set(gpiochip, led_pin, 1);
printk("Led down!\n");
break;
}
return 0;
}
static int pi_led_release(struct inode *inode,struct file *file){
printk("Led has release!\n");
return 0;
}
//file_operations使系统的open,ioctl等函数指针指向我们所写的led_open等函数,
//这样系统才能够调用
static struct file_operations pi_led_dev_fops = {
.owner =THIS_MODULE,
.open =pi_led_open,
.unlocked_ioctl = pi_led_ioctl,
.release = pi_led_release,
};
static int is_right_chip(struct gpio_chip *chip, void *data)
{
if (strcmp(data, chip->label) == 0)
return 1;
return 0;
}
//内核加载后的初始化函数.
static int __init pi_led_init(void)
{
struct device *dev;
int major; //自动分配主设备号
major = alloc_chrdev_region(&pi_led_devno,0,1,DRIVER_NAME);
//register_chrdev 注册字符设备使系统知道有LED这个模块在.
cdev_init(&pi_led_class_dev, &pi_led_dev_fops);
major = cdev_add(&pi_led_class_dev,pi_led_devno,1);
//注册class
pi_led_class = class_create(THIS_MODULE,DRIVER_NAME);
dev = device_create(pi_led_class ,NULL,pi_led_devno,NULL,DRIVER_NAME);
gpiochip = gpiochip_find("bcm2708_gpio", is_right_chip);
gpiochip->direction_output(gpiochip, led_pin, 1);
gpiochip->set(gpiochip, led_pin, 0);
printk("pi led init ok!\n");
return 0;
}
//内核卸载后的销毁函数.
void pi_led_exit(void)
{
gpio_free(led_pin);
device_destroy(pi_led_class,pi_led_devno);
class_destroy(pi_led_class);
cdev_del(&pi_led_class_dev);
unregister_chrdev_region(pi_led_devno, 1);
printk("pi led exit ok!\n");
}
module_init(pi_led_init);
module_exit(pi_led_exit);
MODULE_DESCRIPTION("Rasp Led Driver");
MODULE_AUTHOR("Embbnux Ji < http://blog.csdn.net/embbnux >");
MODULE_LICENSE("GPL");
