【驱动开发】注册字符设备使用gpio设备树节点控制led三盏灯的亮灭

注册字符设备使用gpio设备树节点控制led三盏灯的亮灭

设备树:

【驱动开发】注册字符设备使用gpio设备树节点控制led三盏灯的亮灭_第1张图片

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
// 构建开灯关灯的功能码
#define LED_ON _IOW('l', 1,int)
#define LED_OFF _IOW('l', 0,int)
 
#endif

驱动程序:

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "head.h"
struct class *cls;
struct device *dev;
struct resource *res;
unsigned int irqno;
struct device_node *dnode;
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;
struct cdev *cdev;
unsigned int major = 0;
unsigned int minor = 0;
dev_t devno;
int mycdev_open(struct inode *inode, struct file *file)
{
    unsigned int min = MINOR(inode->i_rdev); // 获取打开的文件的次设备号
    file->private_data = (void *)min;
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}
ssize_t mycdev_read(struct file *file, char __user *user, size_t size, loff_t *lof)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}
ssize_t mycdev_write(struct file *file, const char __user *user, size_t size, loff_t *lof)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    int min = (int)file->private_data; // 获取文件的次设备号
    switch (min)
    {
    case 0: // LED1
        switch (cmd)
        {
        case LED_ON: // 开灯
            gpiod_set_value(gpiono1, 1);
            break;
        case LED_OFF: // 关灯
            gpiod_set_value(gpiono1, 0);
            break;
        }
        break;
    case 1: // LED2
        switch (cmd)
        {
        case LED_ON: // 开灯
            gpiod_set_value(gpiono2, 1);
            break;
        case LED_OFF: // 关灯
            gpiod_set_value(gpiono2, 0);
            break;
        }
        break;
    case 2: // LED3
        switch (cmd)
        {
        case LED_ON: // 开灯
            gpiod_set_value(gpiono3, 1);
            break;
        case LED_OFF: // 关灯
            gpiod_set_value(gpiono3, 0);
            break;
        }
        break;
    }
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}
struct file_operations fops = {
    .open = mycdev_open,
    .read = mycdev_read,
    .write = mycdev_write,
    .release = mycdev_close,
    .unlocked_ioctl = mycdev_ioctl,
};
int pdrv_probe(struct platform_device *pdev) // 当驱动和设备匹配成功后执行
{
    int ret,
        // 1.实例化字符设备驱动对象
        cdev = cdev_alloc();
    if (cdev == NULL)
    {
        printk("申请字符设备驱动对象空间失败\n");
        ret = -EFAULT;
        goto OUT1;
    }
    printk("申请字符设备驱动对象空间成功\n");

    // 2.部分初始化字符设备驱动对象
    cdev_init(cdev, &fops);
    // 3.申请设备号
    if (major == 0) // 动态申请设备号
    {
        ret = alloc_chrdev_region(&devno, minor, 3, "mycdev");
        if (ret)
        {
            printk("动态申请设备号失败\n");
            goto OUT2;
        }
        major = MAJOR(devno);
        minor = MINOR(devno);
    }
    else // 静态指定设备号
    {
        ret = register_chrdev_region(devno, 3, "mycdev");
        if (ret)
        {
            printk("静态设备号失败\n");
            goto OUT2;
        }
    }
    printk("设备号申请成功\n");
    // 4.将字符设备驱动对象注册进内核
    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.自动创建设备节点
    cls = class_create(THIS_MODULE, "mycdev");
    if (IS_ERR(cls))
    {
        printk("向上提交目录失败\n");
        ret = -PTR_ERR(cls);
        goto OUT4;
    }
    printk("向上提交目录成功\n");
    // 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, "mycdev%d", i);
        if (IS_ERR(dev))
        {
            printk("向上提交设备信息失败\n");
            ret = PTR_ERR(dev);
            goto OUT5;
        }
    }
    printk("自动创建设备节点成功\n");

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (res == NULL)
    {
        printk("解析资源失败%d\n", __LINE__);
        return -ENOMEM;
    }
    irqno = platform_get_irq(pdev, 0);
    if (irqno < 0)
    {
        printk("解析资源失败%d\n", __LINE__);
        return -ENOMEM;
    }

    printk("mem:%x irq:%d\n", res->start, irqno);

    // 使用gpio驱动
    dnode = of_find_node_by_path("/myplatform");
    if (dnode == NULL)
    {
        printk("解析设备树节点失败\n");
        return -ENXIO;
    }
    // 解析出GPIO编号并申请
    gpiono1 = gpiod_get_from_of_node(pdev->dev.of_node, "led1-gpio", 0, GPIOD_OUT_LOW, NULL);
    if (IS_ERR(gpiono1))
    {
        printk("GPIO信息解析失败\n");
        return -PTR_ERR(gpiono1);
    }
    gpiono2 = gpiod_get_from_of_node(pdev->dev.of_node, "led2-gpio", 0, GPIOD_OUT_LOW, NULL);
    if (IS_ERR(gpiono2))
    {
        printk("GPIO信息解析失败\n");
        return -PTR_ERR(gpiono2);
    }
    gpiono3 = gpiod_get_from_of_node(pdev->dev.of_node, "led3-gpio", 0, GPIOD_OUT_LOW, NULL);
    if (IS_ERR(gpiono3))
    {
        printk("GPIO信息解析失败\n");
        return -PTR_ERR(gpiono3);
    }
    /*
    gpiod_set_value(gpiono1,1);
    gpiod_set_value(gpiono2,1);
    gpiod_set_value(gpiono3,1);
    */
    printk("GPIO信息解析成功\n");
    return 0;
OUT5:
    // 释放提交成功的设备节点信息
    for (i--; i >= 0; i--)
    {
        device_destroy(cls, MKDEV(major, i));
    }
    // 销毁目录
    class_destroy(cls);
OUT4:
    cdev_del(cdev);
OUT3:
    unregister_chrdev_region(MKDEV(major, minor), 3);
OUT2:
    kfree(cdev);
OUT1:
    return ret;
}
int pdrv_remove(struct platform_device *pdev) // 当设备和驱动分离时执行
{
    // 释放GPIO信息
    gpiod_put(gpiono1);
    gpiod_put(gpiono2);
    gpiod_put(gpiono3);

    // 销毁节点信息
    int i;
    for (i = 0; i < 3; i++)
    {
        device_destroy(cls, MKDEV(major, i));
    }

    // 销毁目录
    class_destroy(cls);
    // 注销驱动
    unregister_chrdev(major, "mychrdev");
    return 0;
}
// 构建设备树匹配表
struct of_device_id oftable[] = {
    {
        .compatible = "hqyj,myplatform",
    },
    {
        .compatible = "hqyj,myplatform1",
    },
    {}, // 防止数组越界
};
// 1.分配驱动信息对象
struct platform_driver pdrv = {
    .probe = pdrv_probe,
    .remove = pdrv_remove,
    .driver = {
        .name = "bbbbb", // 驱动名
        .of_match_table = oftable,
    },
};
// 一键注册宏
module_platform_driver(pdrv);
MODULE_LICENSE("GPL");

应用程序:

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "head.h"

int main(int argc, char const *argv[])
{
    int a, b;
    int fd;
    while (1)
    {

        // 从中断获取我们想实现的功能功能
        printf("请选择要控制的灯:0-LED1,1-LED2,2-LED3\n");
        scanf("%d", &a);
        switch (a)
        {
        case 1:
            fd = open("/dev/mycdev0", O_RDWR);
            break;
        case 2:
            fd = open("/dev/mycdev1", O_RDWR);
            break;
        case 3:
            fd = open("/dev/mycdev2", O_RDWR);
            break;
        }
        if (fd < 0)
        {
            printf("打开设备文件失败\n");
            return -1;
        }
        printf("打开设备文件成功\n");
        printf("请输入想要实现的功能 ");
        printf("0(关灯)1(开灯)\n");
        printf("请输入>>>");
        scanf("%d", &b);
        switch (b)
        {
        case 1:
            ioctl(fd, LED_ON, &b);
            break;
        case 0:
            ioctl(fd, LED_OFF, &b);
            break;
        }
    }
    close(fd);
    return 0;
}

【驱动开发】注册字符设备使用gpio设备树节点控制led三盏灯的亮灭_第2张图片

【驱动开发】注册字符设备使用gpio设备树节点控制led三盏灯的亮灭_第3张图片

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