2.23通过platform总线驱动框架编写LED灯的驱动，编写应用程序测试-编程知识

驱动代码

#include <linux/init.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>#define LED_ON _IOW('l', 1, int)
#define LED_OFF _IOW('l', 0, int)
int major;
char kbuf[128] = {0};
struct class *cls;
struct device *device;
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;
struct device_node *dnode;
struct resource *res;
unsigned int irqno;
///
int mycdev_open(struct inode *inode, struct file *file)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);unsigned long ret;// 向用户空间读取拷贝if (size > sizeof(kbuf)) // 用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小size = sizeof(kbuf);ret = copy_to_user(ubuf, kbuf, size);if (ret) // 拷贝失败{printk("copy_to_user filed\n");return ret;}return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{unsigned long ret;// 从用户空间读取数据if (size > sizeof(kbuf)) // 用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小size = sizeof(kbuf);ret = copy_from_user(kbuf, ubuf, size);if (ret) // 拷贝失败{printk("copy_to_user filed\n");return ret;}return 0;
}
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{switch (cmd){case LED_ON:switch (arg){case 1:gpiod_set_value(gpiono1, 1); // led1输出高电平break;case 2:gpiod_set_value(gpiono2, 1); // led2输出高电平break;case 3:gpiod_set_value(gpiono3, 1); // led2输出高电平break;}break;case LED_OFF:switch (arg){case 1:gpiod_set_value(gpiono1, 0); // led1输出低电平break;case 2:gpiod_set_value(gpiono2, 0); // led2输出低电平break;case 3:gpiod_set_value(gpiono3, 0); // led3输出高电平break;}break;}return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}// 定义操作方法结构体变量并赋值
struct file_operations fops = {.open = mycdev_open,.read = mycdev_read,.write = mycdev_write,.unlocked_ioctl = mycdev_ioctl,.release = mycdev_close,
};
///
// 封装probe函数，当设备和驱动匹配成功之后执行
int pdrv_probe(struct platform_device *dev)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);// 字符设备驱动注册major = register_chrdev(0, "mychrdev", &fops);if (major < 0){printk("字符设备驱动注册失败\n");return major;}printk("字符设备驱动注册成功:major=%d\n", major);// 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");return -PTR_ERR(cls);}printk("向上提交目录成功\n");// 向上提交设备节点信息int i; // 向上提交三次设备节点信息for (i = 0; i < 3; i++){device = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);if (IS_ERR(device)){printk("向上提交设备节点失败\n");return -PTR_ERR(device);}}printk("向上提交设备节点成功\n");// 解析LED灯设备树节点dnode = of_find_node_by_path("/leds");if (dnode == NULL){printk("解析设备树节点失败\n");return -ENXIO;}printk("解析设备树节点成功\n");// 解析LED1的gpio编号gpiono1 = gpiod_get_from_of_node(dnode, "led1-gpio", 0, GPIOD_OUT_LOW, NULL);if (gpiono1 == NULL){printk("解析gpio1编号失败\n");return -ENXIO;}printk("解析gpio1编号成功\n");// 解析LED2的gpio编号gpiono2 = gpiod_get_from_of_node(dnode, "led2-gpio", 0, GPIOD_OUT_LOW, NULL);if (gpiono2 == NULL){printk("解析gpio2编号失败\n");return -ENXIO;}printk("解析gpio2编号成功\n");// 解析LED3的gpio编号gpiono3 = gpiod_get_from_of_node(dnode, "led3-gpio", 0, GPIOD_OUT_LOW, NULL);if (gpiono3 == NULL){printk("解析gpio3编号失败\n");return -ENXIO;}printk("解析gpio3编号成功\n");return 0;
}
// 封装remove函数，用于驱动和设备卸载时执行
int pdrv_remove(struct platform_device *dev)
{// 释放gpio编号gpiod_put(gpiono1);gpiod_put(gpiono2);gpiod_put(gpiono3);printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}
// 构建用于匹配的设备树表
struct of_device_id oftable[] = {{.compatible = "hqyj,myplatform",},{/* end node */}, // 防止数组越界
};
// 分配驱动对象并初始化
struct platform_driver pdrv = {.probe = pdrv_probe,.remove = pdrv_remove,.driver = {.name = "bbbbb",.of_match_table = oftable, // 设置设备树匹配},};
// 一键注册宏
module_platform_driver(pdrv);
MODULE_LICENSE("GPL");

程序代码

#include<stdlib.h>
#include<stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include<unistd.h>
#include<string.h>
#include<sys/ioctl.h>
#include "myled.h"//创建功能码
#define LED_ON _IOW('l',1,int)  
#define LED_OFF _IOW('l',0,int)int main(int argc, char const *argv[])
{int a,b;int fd=open("/dev/myled0",O_RDWR);if(fd<0){printf("打开设备文件失败\n");exit(-1);}while(1){//从终端读取printf("请输入要实现的功能\n");printf("0(关灯) 1(开灯)\n");printf("请输入>");scanf("%d",&a);printf("请输入要控制的灯\n");printf("1(LED1) 2(LED2) 3(LED3)\n");printf("请输入>");scanf("%d",&b);switch(a){case 1:ioctl(fd,LED_ON,b);break;case 0:ioctl(fd,LED_OFF,b);break;}}close(fd);return 0;
}

头文件：

#ifndef __HEAD_H__
#define __HEAD_H__ 
typedef struct{unsigned int MODER;unsigned int OTYPER;unsigned int OSPEEDR;unsigned int PUPDR;unsigned int IDR;unsigned int ODR;
}gpio_t;
#define PHY_LED1_ADDR 0X50006000
#define PHY_LED2_ADDR    0X50007000
#define PHY_LED3_ADDR 0X50006000
#define PHY_RCC_ADDR    0X50000A28//构建功能码
#define LED_ON _IO('l',1)  
#define LED_OFF _IO('l',0)
#endif

效果图：