18、IMX6ULL学习笔记-linux设备树之内核定时器之ioctl函数

一、设备驱动程序

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ide.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#define DeviceName 		"devicetree-timer-ioctl" //设备驱动名称
#define DeviceNodes 	1 					  	 //设备节点个数
#define CLOSE_CMD       _IO(0XEF, 1)          	 //关闭命令               
#define OPEN_CMD        _IO(0XEF, 2)          	 //打开命令             
#define SETPERIOD_CMD   _IOW(0xEF, 3, int)    	 //设置周期
/* 定义一个设备结构体 */
struct mod_struct {
	dev_t devid;			     /* 设备号*/
	struct cdev cdev;		     /* cdev  */
	struct class *class;	  	 /* 类    */
	struct device *device;	 	 /* 设备  */
	int major;				     /* 主设备号 */
	int minor;				     /* 次设备号 */
	struct device_node	*nd;  	 /* 设备节点 */
	int gpio;					 /* GPIO编号*/
	struct timer_list timer;	 /* 定义一个定时器*/
	int timeperiod;				 /* 定时器周期*/
};
struct mod_struct mod_device;	 /* led设备 */
/*
 * @description		: 打开设备
 * @param - inode 	: 传递给驱动的inode
 * @param - filp 	: 设备文件，file结构体有个叫做private_data的成员变量
 * 					  一般在open的时候将private_data指向设备结构体。
 * @return 			: 0 成功;其他 失败
 */
static int kernel_timer_open(struct inode *inode, struct file *filp)
{
	filp->private_data = &mod_device; /* 设置私有数据 */
	return 0;
}
/*
 * @description		: 从设备读取数据 
 * @param - filp 	: 要打开的设备文件(文件描述符)
 * @param - buf 	: 返回给用户空间的数据缓冲区
 * @param - cnt 	: 要读取的数据长度
 * @param - offt 	: 相对于文件首地址的偏移
 * @return 			: 读取的字节数，如果为负值，表示读取失败
 */
static ssize_t kernel_timer_read(struct file *filp, char __user *buf, size_t cnt, loff_t *offt)
{
	return 0;
}
/*
 * @description		: 向设备写数据 
 * @param - filp 	: 设备文件，表示打开的文件描述符
 * @param - buf 	: 要写给设备写入的数据
 * @param - cnt 	: 要写入的数据长度
 * @param - offt 	: 相对于文件首地址的偏移
 * @return 			: 写入的字节数，如果为负值，表示写入失败
 */
static ssize_t kernel_timer_write(struct file *filp, const char __user *buf,size_t cnt, loff_t *offt)
{
	return 0;
}
/*
 * @description		: 关闭/释放设备
 * @param - filp 	: 要关闭的设备文件(文件描述符)
 * @return 			: 0 成功;其他 失败
 */
static int kernel_timer_release(struct inode *inode, struct file *filp)
{
	return 0;
}
static long kernel_timer_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    int ret = 0;
    int value = 0;
    struct mod_struct *dev = file->private_data;
	switch (cmd) {
	case CLOSE_CMD:
        del_timer_sync(&dev->timer);
		break;
	case OPEN_CMD:
        mod_timer(&dev->timer, jiffies + msecs_to_jiffies(dev->timeperiod));
		break;
	case SETPERIOD_CMD:
        ret = copy_from_user(&value, (int *)arg, sizeof(int));
        if(ret < 0) {
            return -EFAULT;
        }
        dev->timeperiod = value;
        mod_timer(&dev->timer, jiffies + msecs_to_jiffies(dev->timeperiod));
		break;
	}
	return ret;
}
/* 设备操作函数 */
static struct file_operations beep_fops = {
	.owner    	=  THIS_MODULE,
	.open     	=  kernel_timer_open,
	.read     	=  kernel_timer_read,
	.write    	=  kernel_timer_write,
	.release  	=  kernel_timer_release,
	.unlocked_ioctl  =  kernel_timer_ioctl,
};
/*
 * @description	: 定时器超时函数
 * @param 		: arg
 * @return 		: 无
 */
static void timer_func(unsigned long arg)
{
    struct mod_struct *dev = (struct mod_struct*)arg;
    static int sta = 1;
    sta = !sta;
    gpio_set_value(dev->gpio, sta);
    mod_timer(&dev->timer, jiffies + msecs_to_jiffies(dev->timeperiod));
}
/*
 * @description	: 定时器超时函数
 * @param 		: dev
 * @return 		: 无
 */
int led_init(struct mod_struct *dev)
{
	int ret = 0;
	/* 1、获取设备节点：/devicetree-leds-pincrl */
	dev->nd = of_find_node_by_path("/devicetree-leds-pincrl");
	if(dev->nd == NULL) {
			printk("devicetree-leds-pincrl node not find!\r\n");
			ret = -EINVAL;
			goto fail_fd;
	} else {
		printk("devicetree-leds-pincrl node find!\r\n");
	}
	/* 2、从设备节点下的led-gpio属性里获取gpio编号 */
	dev->gpio = of_get_named_gpio(dev->nd, "leds-gpio", 0);
	if(dev->gpio < 0) {
			printk("can't get leds-gpio\r\n");
			ret = -EINVAL;
			goto fail_gpio;
	}
	printk("led-gpio num = %d\r\n", dev->gpio);
	/*3、申请gpio(检查是否被占用)*/
	ret = gpio_request(dev->gpio,"led2-gpio");
	if(ret)
	{
		ret = -EBUSY;
		printk("IO %d busy,can't request!\r\n",dev->gpio);
		goto fail_ioreq;
	}
	/*4、设置GPIO1_IO03为输出，并且输出高电平，默认关闭LED灯 */
	ret = gpio_direction_output(dev->gpio,1);
	if(ret < 0) {
			printk("can't set gpio!\r\n");
			goto fail_ioset;
	}
	return 0;
fail_ioset:
	gpio_free(dev->gpio);
fail_ioreq:
fail_gpio:
fail_fd:
	return ret;
}
/*
 * @description	: 驱动出口函数
 * @param 		: 无
 * @return 		: 无
 */
static int __init kernel_timer_init(void)
{
	int ret = 0;
/*一、 注册字符设备驱动 */
	/* 1、创建设备号 */
	if (mod_device.major)
	{		
		mod_device.devid = MKDEV(mod_device.major,0);//设备号起始点(major,0)
		//设备号起始点开始，申请DeviceNodes个设备号
		ret = register_chrdev_region(mod_device.devid,DeviceNodes,DeviceName);
	} 
	else {
		ret = alloc_chrdev_region(&mod_device.devid,0,DeviceNodes,DeviceName);	/* 申请设备号 */
		mod_device.major = MAJOR(mod_device.devid);	/* 获取分配号的主设备号 */
		mod_device.minor = MINOR(mod_device.devid);	/* 获取分配号的次设备号 */	
	}
	if(ret < 0){ printk("设备号申请失败\r\n");goto fail_chrdev; }
	printk("mod_device major=%d,minor=%d\r\n",mod_device.major,mod_device.minor);	
	/* 2、初始化cdev并添加cdev */
	mod_device.cdev.owner = THIS_MODULE;
	cdev_init(&mod_device.cdev,&beep_fops);
	ret = cdev_add(&mod_device.cdev,mod_device.devid,DeviceNodes);
	if(ret < 0){ printk("添加cdev失败！\r\n");goto fail_cdev; }
	/* 3、创建类 */
	mod_device.class = class_create(THIS_MODULE,DeviceName);
	if (IS_ERR(mod_device.class)) { ret = PTR_ERR(mod_device.class);goto fail_class; } 
	/* 4、创建设备节点*/
	mod_device.device = device_create(mod_device.class,NULL,mod_device.devid,NULL,"pinctrl-timer");
	if (IS_ERR(mod_device.device)) { ret = PTR_ERR(mod_device.device);goto fail_device; }
/*二、LED初始化*/
	ret = led_init(&mod_device);
	if(ret < 0){ printk("led_init fail!\r\n");goto fail_ledinit; }
/*三、初始化内核定时器*/
	init_timer(&mod_device.timer);
	mod_device.timer.function = timer_func;
	mod_device.timer.expires  = jiffies + msecs_to_jiffies(500);
	mod_device.timer.data     = (unsigned long)(&mod_device);
	add_timer(&mod_device.timer);
	return 0;
/*X、模块加载失败处理部分*/
fail_ledinit:
	device_destroy(mod_device.class,mod_device.devid);
fail_device:	
	class_destroy(mod_device.class);
fail_class:	
	cdev_del(&mod_device.cdev);
fail_cdev:
	unregister_chrdev_region(mod_device.devid,DeviceNodes);
fail_chrdev:
	return ret;
}
/*
 * @description	: 驱动出口函数
 * @param 		: 无
 * @return 		: 无
 */
static void __exit kernel_timer_exit(void)/*按照相反顺序注销*/
{
	/*一、内核定定时器注销部分*/
	del_timer(&mod_device.timer);/* 删除timer */
	/*二、LED设备注销部分*/
	gpio_set_value(mod_device.gpio,1);/* 卸载驱动的时候关闭LED */
	gpio_free(mod_device.gpio);/*注销gpio*/		
	/*三、设备驱动注销部分*/			
	device_destroy(mod_device.class,mod_device.devid);/*注销设备节点*/
	class_destroy(mod_device.class);/*注销类*/
	cdev_del(&mod_device.cdev);/*注销cdev*/
	unregister_chrdev_region(mod_device.devid,DeviceNodes);/*注销chrdev*/
}
module_init(kernel_timer_init);
module_exit(kernel_timer_exit);
MODULE_LICENSE("GPL");

二、app测试程序

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
/*
 *argc:应用程序参数个数
 *argv[]:具体的参数内容，字符串形式 
 *./timerAPP  <filename>  
 * ./timerAPP /dev/timer
 */
#define CLOSE_CMD      _IO(0XEF, 1)          //关闭命令               
#define OPEN_CMD       _IO(0XEF, 2)          //打开命令             
#define SETPERIOD_CMD  _IOW(0xEF, 3, int)    //设置周期
int main(int argc, char *argv[])
{
    int fd, ret;
    char *filename;
    unsigned char databuf[1];
    unsigned int cmd;
    unsigned int arg;
    unsigned char str[100];

    if(argc != 2) {
        printf("Error Usage!\r\n");
        return -1;
    }

    filename = argv[1];

    fd = open(filename, O_RDWR);
    if(fd < 0) {
        printf("file %s open failed!\r\n", filename);
        return -1;
    }

    /* 循环读取 */
    while(1) {
        printf("Input CMD:");
        ret = scanf("%d", &cmd);
        if(ret !=1 ) {
            gets(str);  /* 防止卡死 */
        }

        if(cmd == 1) {          /* 关闭 */
            ioctl(fd, CLOSE_CMD, &arg);  
        } else if(cmd == 2) {   /* 打开 */
            ioctl(fd, OPEN_CMD, &arg); 
        } else if(cmd == 3) {    /* 设置周期 */
            printf("Please input timer period->");
            ret = scanf("%d", &arg);
            printf("Your input message->%d\r\n",arg);
            if(ret !=1 ) {
                gets(str);
            }
            ioctl(fd, SETPERIOD_CMD, &arg); 
        }
    }
    close(fd);
    return 0;
}