【玄铁杯第三届RISC-V应用创新大赛】LicheePi 4A 基于人体红外传感器的使用

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【玄铁杯第三届RISC-V应用创新大赛】LicheePi 4A 基于人体红外传感器的使用 [复制链接]

<i class="pstatus"> 本帖最后由 ccccccc@ 于 2023-12-6 23:50 编辑 </i>

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人体红外传感器是一种能够感知人体红外辐射并转换为电信号输出的传感器。它通常由红外敏感元件、信号处理电路和输出接口组成。人体红外传感器广泛应用于安防、智能家居、医疗等领域，可以实现人体检测、运动检测等功能。

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`图片来源于http://henrysbench.capnfatz.com`
可以通过调节电路，来进行传感器检测的时间、距离灵敏度。将输出引脚连接到GPIO1_IO5 。

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所以对应的编号为381.
本来想使用gpio中断方式来使用人体红外传感器来判断人体的接近，达到无接触控制（比如开灯、烧水、关灯等智能家居的控制，减轻老人在家居智能化环境下的使用负担），但是编写驱动一直报错：

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我的驱动代码与Makefile文件如下：
```c
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/capability.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <asm/mach-types.h>
#include <asm/uaccess.h>
#include <asm/therm.h>
#include <linux/string.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqreturn.h>
#include <linux/module.h>

static int major;
static unsigned char buff[100];
static struct class *sr501_class;

/*sr501 args*/
unsigned int sr501_gpio = 381;  //对照原理图   sr501  GPIO1_IO5 381
int sr501_irq; //存储中断号

static irqreturn_t sr501_handle(int irqs, void *dev_id)
{
    int value;
    /*读取sr501的值*/
    value = gpio_get_value(sr501_gpio);
    printk("this is sr501_handle, irq = %d\n",irqs);
    printk("read sr501 = %d, %s\n", value, value == 1 ? "people" : "people go out");

return IRQ_HANDLED;
}

static int sr501_open (struct inode *node, struct file *filp)
{
    printk("sr501_open\n");
    printk("%s %s %d\n",__FILE__, __FUNCTION__, __LINE__);

return 0;
}

static ssize_t sr501_read (struct file *filp, char *buf, size_t size, loff_t *offset)
{
    int err;

printk("sr501_drv_read\n");

/*read sr501_gpio value*/
    buff[0] = gpio_get_value(sr501_gpio);
    
    err = copy_to_user(buf, buff, 1);
    return buff[0];
}

static int sr501_release (struct inode *node, struct file *filp)
{
    printk("sr501_release\n");
    return 0;
}

/*1.定义 file_operations 结构体*/
static const struct file_operations sr501_fops = {
  .owner         = THIS_MODULE,
    .read        = sr501_read,
    .open        = sr501_open,
    .release  = sr501_release,
};

/*3.入口函数*/
static int sr501_init(void)
{
    int err;
    /************* 1.注册设备，返回设备号 ************/
    major = register_chrdev(0,"sr501_drv",&sr501_fops);

/*2.在内核中创建设备*/
    sr501_class = class_create(THIS_MODULE, "sr501_class");
    if (IS_ERR(sr501_class)) {
        printk("sr501 class create failed!\n");
    }

/*3.在/dev下面创建设备节点*/
    device_create(sr501_class, NULL, MKDEV(major, 0), NULL, "sr501_drv");
    
    /************* 4.sr501引脚申请中断 ************/
    sr501_irq = gpio_to_irq(sr501_gpio);
    printk("request irq = %d\n", sr501_irq);
    /*上升沿和下降沿都触发，上升沿-有人，下降沿-人走了*/
    err = request_irq(sr501_irq, sr501_handle, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, 
                    "sr501_irq", NULL);// 
    if(err != 0){
        printk("request irq error!\n");
    }
    
    return 0;
}

/*4.退出函数*/
static int sr501_exit(void)
{
    //卸载设备
    unregister_chrdev(major,"sr501_fops");

//销毁设备
    device_destroy(sr501_class, MKDEV(major, 0));
    //删除设备类
    class_destroy(sr501_class);

/*释放sr501_gpio引脚中断*/
    free_irq(sr501_irq, NULL);

printk("sr501_exit\n");

return 0;
}

module_init(sr501_init);
module_exit(sr501_exit);
MODULE_LICENSE("GPL");

```
Makefile：
```c
ifneq ($(KERNELRELEASE),)
obj-m := sr501_ko.o
else
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
default:
    $(MAKE) -C $(KERNELDIR) M=$(PWD) modules
endif
```