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/*
廢話：在展訊平臺移植 spi 裝置的時候發現完成 dts 和 driver中的 of_match_table 後，在 init時 spi_driver_register 返回0（註冊成功）但是 probe 卻無法跑起來，一直沒有 找出來原因。
於是改用 board_info 的方式直接在 driver 中註冊裝置資訊。
*/

i2c 裝置模型

#include <linux/module.h>
#include <linux/i2c.h>
 


#define SENSOR_BUS_NUM 0
#define SENSOR_SLAVE_ADDRESS 0x3e
#define SENSOR_NAME "sensor"
struct i2c_client *sensor_client=NULL;

static int sensor_probe(struct i2c_client *client,const struct i2c_device_id *id)
{
    sensor_client=client;
    return 0;
}

static int sensor_remove(struct i2c_client *client)
{
    return
 
 0;
}
//首先需要一個 id_table
static const struct i2c_device_id sensor_id[] = {
    {SENSOR_NAME, 0},
    { }
};
MODULE_DEVICE_TABLE(i2c, sensor_id);
//在 driver中新增 id_table
static struct i2c_driver sensor_driver = {
    .driver = {
             .name = SENSOR_NAME,
    },
    .probe    = sensor_probe,
    .remove   = sensor_remove,
    .id_table = sensor_id,
};
//填充 board_info 
 

static struct i2c_board_info sensor_device = {
    I2C_BOARD_INFO("hmc5883l-i2c", SENSOR_SLAVE_ADDRESS),
};

static int __init sensor_init(void)
{
    struct i2c_adapter *adap;
    struct i2c_client *client;

    adap = i2c_get_adapter(sensor_bus_num);
    if (!adap) {
        printk("i2c adapter %d\n",sensor_bus_num);
        return -ENODEV;
    } else {
        printk("get ii2 adapter %d ok\n", sensor_bus_num);
        client = i2c_new_device(adap, &sensor_device);
    }
    if (!client) {
        printk("get i2c client %s @ 0x%02x fail!\n", sensor_device.type,
                sensor_device.addr);
        return -ENODEV;
    } else {
        printk("get i2c client ok!\n");
    }
    i2c_put_adapter(adap);
    i2c_add_driver(&sensor_driver);
    printk("sensor init success!\n");
    return 0;
}

static void __exit sensor_exit(void)
{
    i2c_del_driver(&sensor_driver);
    if(sensor_client!=NULL)
    i2c_unregister_device(sensor_client);
    printk("Module removed\n");
}

module_init(sensor_init);
module_exit(sensor_exit);
ODULE_AUTHOR("GPL");
ODULE_LICENSE("GPL");

spi裝置驅動模型

spi的驅動模板如下

#include <linux/module.h>
#include <linux/spi/spi.h>

#define DEVICE_NAME   "sensor"
#define SENSOR_SPI_BUS 0
struct spi_device *sensor_spi=NULL;


int sensor_spi_write(void)
{
    return 0;
}

int sensor_spi_read(void)
{
    return 0;
}

static const struct spi_device_id sensor_spi_id[] = {
    { DEVICE_NAME, 0 },
    { }
};

MODULE_DEVICE_TABLE(spi, sensor_spi_id);

static int  sensor_probe(struct spi_device *spi)
{
    sensor_spi=spi;
    return 0;
}

static int  sensor_remove(struct spi_device *spi)
{
    return 0;
}

static struct spi_driver sensor_driver = {
    .driver = {
        .name  = DEVICE_NAME,
        .owner = THIS_MODULE,
    },
    .probe    =  sensor_probe,
    .remove   =  sensor_remove,
    .id_table =  sensor_spi_id,
};

static __init int sensor_spi_init(void)
{
    int status=-1;
    struct spi_master *master;
    struct spi_device *spi;
    struct spi_board_info chip =
    {
        .modalias     = DEVICE_NAME,
        .mode         = 0x00,
        .bus_num      = 0,
        .chip_select  = 0,
        .max_speed_hz = 2000000,
    };
    spi_register_driver(&sensor_driver);
    if (status<0)
    {
        pr_err("%s: spi_register_driver spi_driver failure. status = %d\n", __func__, status);
    }
    pr_err("%s: spi_register_driver spi_driver success. status = %d\n", __func__, status);
    master = spi_busnum_to_master(SENSOR_SPI_BUS);
    if (!master)
    {
        status = -ENODEV;
        goto error_busnum;
    }
    spi = spi_new_device(master, &chip);
    if (!spi)
    {
        status = -EBUSY;
        goto error_mem;
    }
    return status;

error_mem:
error_busnum:
    spi_unregister_driver(&sensor_driver);
    return status;
}

static __exit void sensor_spi_exit(void)
{
    spi_unregister_driver(&sensor_driver);
    if(sensor_spi!=NULL)
    spi_unregister_device(sensor_spi);
}

module_init(sensor_spi_init);
module_exit(sensor_spi_exit);
MODULE_LICENSE("GPL v2");