基于linux4.9写一个内核IIC驱动AHT20采集温湿度的功能代码代码

以下是一个基于Linux 4.9内核的AHT20 IIC驱动，用于采集温湿度的功能代码。在此之前，您需要先编写一个用户空间程序，用于打开IIC设备节点并读取温湿度数据。以下代码假设您已经完成了这一步骤，并定义了一个名为`aht20_read`的函数，用于读取AHT20的温湿度数据。

#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/kernel.h>

// AHT20 I2C Address
#define AHT20_I2C_ADDR 0x38

// AHT20 Commands
#define AHT20_CMD_INIT 0b1110001
#define AHT20_CMD_MEASURE 0b10101100
#define AHT20_CMD_SOFT_RESET 0b10111010

static int aht20_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
    int ret;
    u8 buf[3];

    // Initialize AHT20
    buf[0] = AHT20_CMD_INIT;
    ret = i2c_master_send(client, buf, 1);
    if (ret < 0) {
        dev_err(&client->dev, "Failed to send AHT20 initialization command\n");
        return ret;
    }
    msleep(20);

    // Soft reset AHT20
    buf[0] = AHT20_CMD_SOFT_RESET;
    ret = i2c_master_send(client, buf, 1);
    if (ret < 0) {
        dev_err(&client->dev, "Failed to send AHT20 soft reset command\n");
        return ret;
    }
    msleep(20);

    return 0;
}

static int aht20_read_measurement(struct i2c_client *client, u16 *humidity, u16 *temperature)
{
    int ret;
    u8 buf[6];

    // Send measure command to AHT20
    buf[0] = AHT20_CMD_MEASURE;
    ret = i2c_master_send(client, buf, 1);
    if (ret < 0) {
        dev_err(&client->dev, "Failed to send AHT20 measure command\n");
        return ret;
    }
    msleep(80);

    // Read measurement data from AHT20
    ret = i2c_master_recv(client, buf, sizeof(buf));
    if (ret < 0) {
        dev_err(&client->dev, "Failed to read AHT20 measurement data\n");
        return ret;
    }

    // Convert measurement data to humidity and temperature values
    *humidity = (buf[1] << 12) | (buf[2] << 4) | (buf[3] >> 4);
    *temperature = ((buf[3] & 0x0F) << 16) | (buf[4] << 8) | buf[5];

    return 0;
}

static int aht20_read(struct i2c_client *client, u16 *humidity, u16 *temperature)
{
    int ret;

    // Read measurement data from AHT20
    ret = aht20_read_measurement(client, humidity, temperature);
    if (ret < 0) {
        dev_err(&client->dev, "Failed to read AHT20 measurement data\n");
        return ret;
    }

    return 0;
}

static const struct i2c_device_id aht20_id[] = {
    { "aht20", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, aht20_id);

static struct i2c_driver aht20_driver = {
    .driver = {
        .name = "aht20",
    },
    .probe = aht20_probe,
    .id_table = aht20_id,
};

module_i2c_driver(aht20_driver);

MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("AHT20 IIC Driver");
MODULE_LICENSE("GPL");

这段代码实现了从AHT20读取温湿度数据的功能。在用户空间程序中，您可以打开IIC设备节点并调用`aht20_read`函数来读取温湿度数据。例如：

int fd = open("/dev/i2c-1", O_RDWR);
if (fd < 0) {
    perror("Failed to open IIC device node");
    return -1;
}

int addr = 0x38;
if (ioctl(fd, I2C_SLAVE, addr) < 0) {
    perror("Failed to set IIC slave address");
    close(fd);
    return -1;
}

u16 humidity, temperature;
if (read(fd, &humidity, sizeof(humidity)) != sizeof(humidity)) {
    perror("Failed to read humidity data");
    close(fd);
    return -1;
}

if (read(fd, &temperature, sizeof(temperature)) != sizeof(temperature)) {
    perror("Failed to read temperature data");
    close(fd);
    return -1;
}

printf("Humidity: %d%%\n", humidity);
printf("Temperature: %d.%d C\n", temperature / 100, temperature % 100);

close(fd);

请注意，这只是一个示例代码，并且可能需要根据您的具体需求进行修改和调整。在实际使用中，请务必小心谨慎，以确保您的设备和数据的安全。