platform总线实现led灯亮灭

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头文件

#ifndef __HEAD_H__
#define __HEAD_H__#define LED_ON _IO('l', 1)
#define LED_OFF _IO('l', 0)
#endif

应用程序代码

#include <stdio.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include "head.h"int main(int argc, char const *argv[])
{int fd = open("/dev/myled0", O_RDWR);if(fd < 0){printf("打开设备文件失败\n");return -1;}int a;while(1){printf("请选择开灯or关灯(0 关灯) (1 开灯)");scanf("%d", &a);switch (a){case 0:ioctl(fd, LED_OFF);break;case 1:ioctl(fd, LED_ON);break;default:break;}}return 0;
}

驱动代码

#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include "head.h"//定义变量，设备驱动对象
struct cdev *cdev;
//定义变量，主设备号，次设备号，设备号
unsigned int major = 0;
unsigned int minor = 0;
//定义变量，保存向上提交目录信息的对象指针
struct class *cls;
//定义变量，向上提交设备节点信息的对象指针
struct device *dev;
dev_t devno;
//定义变量，GOIO对象
struct gpio_desc *gpiono[3];//封装open方法
int mycdev_open(struct inode *inode, struct file *file)
{return 0;
}
//封装close方法
int mycdev_close(struct inode *inode, struct file *file)
{return 0;
}
//封装ioctl方法
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{switch(cmd){int i;case LED_ON:    for(i=0; i<3; i++){gpiod_set_value(gpiono[i], 1);}break;case LED_OFF:for(i=0; i<3; i++){gpiod_set_value(gpiono[i], 0);}break;}return 0;
}
//封装操作方法结构体
struct file_operations fop={.open = mycdev_open,.release = mycdev_close,.unlocked_ioctl = mycdev_ioctl,
};//分布注册设备驱动和创建设备文件函数声明int __register_file(void);
//封装probe函数，设备信息与驱动信息匹配成功执行
int platform_probe(struct platform_device *pdev)
{//分布注册设备驱动和创建设备文件__register_file();//解析GPIO节点解析GPIO对象int i;for(i=0; i<3; i++){gpiono[i] = gpiod_get_from_of_node(pdev->dev.of_node, "led-gpios", i, GPIOD_OUT_LOW, NULL);if(IS_ERR(gpiono[i])){printk("解析GPIO对象失败\n");return -PTR_ERR(gpiono[i]);}}return 0;
}
//分装remove函数，设备信息与驱动信息分离时执行
int platform_remove(struct platform_device *pdev)
{//释放GPIO对象int i;//销毁设备节点for(i=0; i<3; i++){gpiod_put(gpiono[i]);device_destroy(cls, MKDEV(major, i));}//销毁设备目录class_destroy(cls);//注销字符设备驱动cdev_del(cdev);//释放设备号unregister_chrdev_region(MKDEV(major, minor), 3);//释放设备驱动对象空间kfree(cdev);return 0;
}
// struct platform_driver {
// 	int (*probe)(struct platform_device *);
// 	int (*remove)(struct platform_device *);
// 	void (*shutdown)(struct platform_device *);
// 	int (*suspend)(struct platform_device *, pm_message_t state);
// 	int (*resume)(struct platform_device *);
// 	struct device_driver driver;
// 	const struct platform_device_id *id_table;
// 	bool prevent_deferred_probe;
// };
// struct of_device_id {
// 	char	name[32];
// 	char	type[32];
// 	char	compatible[128];
// 	const void *data;
// };
//构建设备树匹配表
struct of_device_id oftable[]={{.compatible = "hqyj,myplatform"},{.compatible = "hqyj,myplatform1"},
};
//分配驱动信息对象并初始化
struct platform_driver pdrv={.probe = platform_probe,.remove = platform_remove,.driver={.name = "myplatform",.of_match_table = oftable,},
};// static int __init mycdev_init(void)
// {
//     //注册驱动信息对象
//     platform_register_drivers(&pdrv);
//     return 0;
// }
// static void __exit mycdev_exit(void)
// {
//     //注销驱动信息对象
//     platform_unregister_drivers(&pdrv);// }
//一键注册宏
module_platform_driver(pdrv);
//分布注册设备驱动和创建设备文件函数声明int __register_file(void){//1.申请设备驱动对象cdev = cdev_alloc();if(NULL == cdev){printk("申请设备驱动对象失败\n");goto out1;}printk("申请设备驱动对象成功\n");//2.初始化设备驱动对象cdev_init(cdev, &fop);//3.申请设备号if(0 == major){int ret = alloc_chrdev_region(&devno, 0, 3, "mychrdev");if(ret){printk("动态申请设备号失败");goto out2;}major = MAJOR(devno);minor = MINOR(devno);printk("动态申请设备号成功\n");}else{int ret = register_chrdev_region(MKDEV(major, minor), 3, "mychrdev");if(ret){printk("静态指定设备号失败\n");goto out2;}printk("静态指定设备号成功\n");}//4.注册字符设备驱动int ret =cdev_add(cdev, MKDEV(major, minor), 3);if(ret){printk("注册字符设备驱动失败\n");goto out3;}printk("注册字符设备驱动成功\n");//5.向上提交目录cls = class_create(THIS_MODULE, "mychrdev");if(IS_ERR(cls)){printk("向上提交目录失败\n");goto out4;}printk("向上提交目录成功\n");//6.向上提交设备节点int i;for(i=0; i<3; i++){dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);if(IS_ERR(dev)){printk("向上提交设备节点失败");goto out5;}}printk("向上提交设备节点成功\n");return 0;out5://销毁设备节点for(--i; i>=0; i++){device_destroy(cls, MKDEV(major, i));}//销毁设备目录class_destroy(cls);out4://注销字符设备驱动cdev_del(cdev);out3://释放设备号unregister_chrdev_region(MKDEV(major, minor), 3);out2://释放设备驱动对象空间kfree(cdev);out1:return -1;}
//
//module_init(mycdev_init);
//module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

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