驱动开发day8（8.1）

编写LED灯的驱动，使用GPIO子系统，里面添加按键的中断处理

1.应用程序发送指令控制LED亮灭

2.按键1 按下，led1电位反转 按键2按下，led2电位反转 按键3 按下，led3电位反转

驱动程序

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/of_irq.h>
#include <linux/interrupt.h>
#include <linux/of_gpio.h>

//功能码
#define LED_ON _IO('l',1)
#define LED_OFF _IO('l',0)

// 定义一个变量保存主设备号
unsigned int major;
char kbuf[128] = {0};
unsigned int led1;
unsigned int led2;
unsigned int led3;

struct class *cls;
struct device *dev;
struct device_node *devn;
unsigned int irqno1;
unsigned int irqno2;
unsigned int irqno3;

// 中断处理函数
irqreturn_t myirq_handle1(int irq, void *dev)
{
    printk("key1 press\n");
    gpio_set_value(led1, !gpio_get_value(led1));
    return IRQ_HANDLED;
}
irqreturn_t myirq_handle2(int irq, void *dev)
{
    printk("key2 press\n");
    gpio_set_value(led2, !gpio_get_value(led2));
    return IRQ_HANDLED;
}
irqreturn_t myirq_handle3(int irq, void *dev)
{
    printk("key3 press\n");
    gpio_set_value(led3, !gpio_get_value(led3));
    return IRQ_HANDLED;
}

int mycdev_open(struct inode *inode, struct file *file)
{
    int a = inode->i_rdev;
    file->private_data = (void *)MINOR(a);
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}

ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *loff)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    unsigned long ret;
    if (size > sizeof(kbuf))
    {
        size = sizeof(kbuf);
    }
    ret = copy_to_user(ubuf, kbuf, size);
    if (ret)
    {
        printk("copy_to_user failed\n");
        return ret;
    }
    return 0;
}

ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *loff)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    if (size > sizeof(kbuf))
    {
        size = sizeof(kbuf);
    }
    long ret;
    ret = copy_from_user(kbuf, ubuf, size);
    if (ret)
    {
        printk("copy_from_user failed\n");
        return -EIO;
    }

    return 0;
}

int mycdev_close(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}

long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    unsigned int a = (unsigned int)file->private_data;
    switch (a)
    {
    case 0:
        switch (cmd)
        {
        case LED_ON:
            gpio_set_value(led1, 1);
            break;
        case LED_OFF:
            gpio_set_value(led1, 0);
            break;
        }
        break;
    case 1:
        switch (cmd)
        {
        case LED_ON:
            gpio_set_value(led2, 1);
            break;
        case LED_OFF:
            gpio_set_value(led2, 0);
            break;
        }
        break;
    case 2:
        switch (cmd)
        {
        case LED_ON:
            gpio_set_value(led3, 1);
            break;
        case LED_OFF:
            gpio_set_value(led3, 0);
            break;
        }
        break;
    }
    return 0;
}
struct file_operations fops = {
    .open = mycdev_open,
    .read = mycdev_read,
    .write = mycdev_write,
    .release = mycdev_close,
    .unlocked_ioctl = mycdev_ioctl,
};
int irq_init(void)
{
    int ret;
    // 解析按键的设备树节点
    devn = of_find_node_by_path("/myirq");
    if (NULL == devn)
    {
        printk("解析设备树节点失败\n");
        return -EFAULT;
    }
    printk("解析设备树节点成功\n");
    // 根据设备树节点解析出软中断号
    irqno1 = irq_of_parse_and_map(devn, 0);
    if (!irqno1)
    {
        printk("解析软中断号失败\n");
        return -ENXIO;
    }
    printk("解析软中断号成功 irqno1=%d\n", irqno1);

    irqno2 = irq_of_parse_and_map(devn, 1);
    if (!irqno2)
    {
        printk("解析软中断号失败\n");
        return -ENXIO;
    }
    printk("解析软中断号成功 irqno2=%d\n", irqno2);

    irqno3 = irq_of_parse_and_map(devn, 2);
    if (!irqno3)
    {
        printk("解析软中断号失败\n");
        return -ENXIO;
    }
    printk("解析软中断号成功 irqno3=%d\n", irqno3);

    // 注册中断
    ret = request_irq(irqno1, myirq_handle1, IRQF_TRIGGER_FALLING, "key1", NULL);
    if (ret)
    {
        printk("注册中断失败\n");
        return ret;
    }
    printk("注册中断成功\n");
    ret = request_irq(irqno2, myirq_handle2, IRQF_TRIGGER_FALLING, "key2", NULL);
    if (ret)
    {
        printk("注册中断失败\n");
        return ret;
    }
    printk("注册中断成功\n");
    ret = request_irq(irqno3, myirq_handle3, IRQF_TRIGGER_FALLING, "key3", NULL);
    if (ret)
    {
        printk("注册中断失败\n");
        return ret;
    }
    printk("注册中断成功\n");
    return 0;
}

static int __init mycdev_init(void)
{
    int i, ret;
    irq_init();
    devn = of_find_node_by_path("/leds");
    if (NULL == devn)
    {
        printk("解析设备树节点失败\n");
        return -EFAULT;
    }
    printk("解析设备树节点成功\n");
    // 根据解析到的设备树节点指针解析出LED的gpio编号
    led1 = of_get_named_gpio(devn, "led1-gpios", 0);
    if (led1 < 0)
    {
        printk("解析led1编号失败\n");
        return led1;
    }
    printk("解析led1编号成功\n");
    // 申请led编号
    ret = gpio_request(led1, NULL);
    if (ret)
    {
        printk("申请led编号失败\n");
        return ret;
    }
    printk("申请led编号成功\n");
    led2 = of_get_named_gpio(devn, "led2-gpios", 0);
    if (led2 < 0)
    {
        printk("解析led2编号失败\n");
        return led2;
    }
    printk("解析led1编号成功\n");
    // 申请led编号
    ret = gpio_request(led2, NULL);
    if (ret)
    {
        printk("申请led编号失败\n");
        return ret;
    }
    printk("申请led编号成功\n");
    led3 = of_get_named_gpio(devn, "led3-gpios", 0);
    if (led3 < 0)
    {
        printk("解析led3编号失败\n");
        return led3;
    }
    printk("解析led3编号成功\n");
    // 申请led编号
    ret = gpio_request(led3, NULL);
    if (ret)
    {
        printk("申请led编号失败\n");
        return ret;
    }
    printk("申请led编号成功\n");
    // 注册字符设备驱动
    major = register_chrdev(0, "mychrdev", &fops);
    if (major < 0)
    {
        printk("register error\n");
        return major;
    }
    printk("register success\n");

    cls = class_create(THIS_MODULE, "myled");
    if (IS_ERR(cls))
    {
        printk("向上提交目录失败\n");
        return -PTR_ERR(cls);
    }
    printk("向上提交目录信息成功]\n");

    for (i = 0; i < 3; i++)
    {
        dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
        if (IS_ERR(dev))
        {
            printk("向上提交结点设备信息失败\n");
            return -PTR_ERR(dev);
        }
    }
    printk("向上提交设备节点成功\n");

    return 0;
}

static void __exit mycdev_exit(void)
{
    // 注销中断
    free_irq(irqno1, NULL);
    free_irq(irqno2, NULL);
    free_irq(irqno3, NULL);

    // 释放led编号
    gpio_put(led1);
    gpio_put(led2);
    gpio_put(led3);
    // 销毁节点信息
    int i;
    for (i = 0; i < 3; i++)
    {
        device_destroy(cls, MKDEV(major, i));
    }

    // 销毁目录信息
    class_destroy(cls);
    // 注销字符设备驱动
    unregister_chrdev(major, "mycdev");
}

module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用程序文章来源地址https://www.toymoban.com/news/detail-623296.html

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
//功能码
#define LED_ON _IO('l',1)
#define LED_OFF _IO('l',0)

int main(int argc, char const *argv[])
{
    int a, b, c;
    char buf[128] = {0};
    printf("invoking open\n");
    int fd1 = open("/dev/myled0", O_RDWR);
    if (fd1 < 0)
    {
        printf("open file failed");
        exit(-1);
    }
    int fd2 = open("/dev/myled1", O_RDWR);
    if (fd2 < 0)
    {
        printf("open file failed");
        exit(-1);
    }
    int fd3 = open("/dev/myled2", O_RDWR);
    if (fd3 < 0)
    {
        printf("open file failed");
        exit(-1);
    }

    while (1)
    {

        printf("请选择LED灯1（LED1）2(LED2) 3(LED3)>");
        scanf("%d", &b);
        printf("请输入控制指令：0（关灯） 1（开灯）>");
        scanf("%d", &a);
        switch (b)
        {
        case 1:
            switch (a)
            {
            case 1:
                ioctl(fd1, LED_ON);
                break;
            case 0:
                ioctl(fd1, LED_OFF);
                break;
            }
            break;
        case 2:
            switch (a)
            {
            case 1:
                ioctl(fd2, LED_ON);
                break;
            case 0:
                ioctl(fd2, LED_OFF);
                break;
            }
            break;
        case 3:
            switch (a)
            {
            case 1:
                ioctl(fd3, LED_ON);
                break;
            case 0:
                ioctl(fd3, LED_OFF);
                break;
            }
            break;
        }
    }
    printf("invoking close\n");
    close(fd1);
    close(fd2);
    close(fd3);
    return 0;
}

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