MPU6050带字符驱动的i2c从设备驱动2

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <linux/mutex.h>

#include <linux/workqueue.h>

#include <linux/i2c.h>

#include <linux/types.h>

#include "log.h"

#include "mpu6050_reg.h"

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Kevin Liu");

struct axis_data {

s16 value;

int standby;

};

struct sub_sensor {

int st; // self-test

int reset; // reset

int sel; // full scale range

struct axis_data x;

struct axis_data y;

struct axis_data z;

};

struct temp_sensor {

int enable;

int reset;

s16 value;

};

struct pwr_mgmt {

int reset;

int sleep;

int cycle;

int cycle_HZ;

int clksel;

int all_standby;

};

struct mpu6050_data {

struct mutex lock;

struct i2c_client *client;

struct delayed_work work;

struct workqueue_struct *wq;

int delay_ms;

struct sub_sensor gyro;

struct sub_sensor accel;

struct temp_sensor temp_s;

struct pwr_mgmt power;

int dlph;

int dhph;

};

enum {

RANGE,

LSB

};

static float accel_sel[][2] = {

{2, 16384},

{4, 8192},

{8, 4096},

{16, 2048}

};

static float gyro_sel[][2] = {

{250, 131},

{500, 65.5},

{1000, 32.8},

{2000, 16.4}

};

static void mpu6050_enable(struct mpu6050_data *mpu6050)

{

struct i2c_client *client = mpu6050->client;

i2c_smbus_write_byte_data(client, MPU6050_REG_PWR_MGMT_1, 0);

}

static void mpu6050_disable(struct mpu6050_data *mpu6050)

{

struct i2c_client *client = mpu6050->client;

i2c_smbus_write_byte_data(client, MPU6050_REG_PWR_MGMT_1,

1 << PWR_1_SLEEP_OFFSET);

}

static void mpu6050_reset(struct mpu6050_data *mpu6050)

{

struct i2c_client *client = mpu6050->client;

i2c_smbus_write_byte_data(client, MPU6050_REG_PWR_MGMT_1,

1 << PWR_1_DEVICE_RESET_OFFSET);

}

/*

* Get gyro/accel/temprature data

* @type : 0 - gyro

* 1 - accel

* 2 - temprature

*/

static int mpu6050_read_data(struct mpu6050_data *mpu6050, int type)

{

s16 values[3];

int i, addr, ret;

struct i2c_client *client = mpu6050->client;

switch(type) {

case 0:

addr = MPU6050_REG_GYRO_XOUT_H;

break;

case 1:

addr = MPU6050_REG_ACCEL_XOUT_H;

break;

case 2:

addr = MPU6050_REG_TEMP_OUT_H;

break;

default:

addr = MPU6050_REG_GYRO_XOUT_H;

break;

}

if (type == 0 || type == 1) {

ret = i2c_smbus_read_i2c_block_data(client, addr,

6, (u8 *)values);

if (ret < 0) {

E("error read gyro\n");

return ret;

}

for (i = 0; i < 3; i++) {

values[i] = be16_to_cpu(values[i]);

}

} else if (type == 2) {

ret = i2c_smbus_read_i2c_block_data(client, addr,

2, (u8 *)values);

if (ret < 0) {

E("error read gyro\n");

return ret;

}

for (i = 0; i < 1; i++) {

values[i] = be16_to_cpu(values[i]);

}

}

switch(type) {

case 0:

mpu6050->gyro.x.value = values[0];

mpu6050->gyro.y.value = values[1];

mpu6050->gyro.z.value = values[2];

break;

case 1:

mpu6050->accel.x.value = values[0];

mpu6050->accel.y.value = values[1];

mpu6050->accel.z.value = values[2];

break;

case 2:

mpu6050->temp_s.value = values[0];

break;

default:

break;

}

return 0;

}

static int mpu6050_read_gyro(struct mpu6050_data *mpu6050)

{

return mpu6050_read_data(mpu6050, 0);

}

static int mpu6050_read_accel(struct mpu6050_data *mpu6050)

{

return mpu6050_read_data(mpu6050, 1);

}

static int mpu6050_read_temprature(struct mpu6050_data *mpu6050)

{

return mpu6050_read_data(mpu6050, 2);

}

static void mpu6050_dump_all(struct mpu6050_data *mpu6050)

{

D("Gyro(X:%d Y:%d Z:%d)\tAccel(X:%d Y:%d Z:%d)\tTemp:%d\n",

mpu6050->gyro.x.value, mpu6050->gyro.y.value,

mpu6050->gyro.z.value, mpu6050->accel.x.value, mpu6050->accel.y.value,

mpu6050->accel.z.value, mpu6050->temp_s.value);

}

static void mpu6050_work(struct work_struct *work)

{

int ret;

struct mpu6050_data *mpu6050 = container_of(

(struct delayed_work *)work, struct mpu6050_data, work);

mpu6050_read_gyro(mpu6050);

mpu6050_read_accel(mpu6050);

mpu6050_read_temprature(mpu6050);

mpu6050_dump_all(mpu6050);

schedule_delayed_work(&mpu6050->work,

msecs_to_jiffies(mpu6050->delay_ms));

}

static int mpu6050_probe(struct i2c_client *client,

const struct i2c_device_id *id)

{

struct mpu6050_data *mpu6050;

u16 version;

D("Probe match happend, ID %s\n", id->name);

if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {

E("I2C check error\n");

return -EINVAL;

}

mpu6050 = kzalloc(sizeof(*mpu6050), GFP_KERNEL); //申请内存

if (!mpu6050) {

E("Mem error\n");

return -ENOMEM;

} else

D("Alloc OK\n");

mpu6050->client = client;

i2c_set_clientdata(client, mpu6050); //mmpu6050在clent中注册

mutex_init(&mpu6050->lock);

mpu6050->delay_ms = 1000;

D("Set OK\n");

INIT_DELAYED_WORK(&mpu6050->work, mpu6050_work);

D("Work queue OK\n");

//INIT_DELAYED_WORK 初始化带延时的工作队列work，将mpu6050_work这个函数放到工作队列中，然后等到调用schedule_delayed_work时执行。

version = i2c_smbus_read_byte_data(client, MPU6050_REG_WHO_AM_I);

if (version != 0x68) {

E("Version check error 0x%X, skip\n", version);

goto free_all;

} else

D("Version Check OK\n");

// 读ID

mpu6050_reset(mpu6050);

mpu6050_enable(mpu6050);

schedule_delayed_work(&mpu6050->work,

msecs_to_jiffies(mpu6050->delay_ms));

//这里调用异步执行mpu6050_work这个函数。

return 0;

free_all:

kfree(mpu6050);

E("A oh!!!ooops...\n");

return -EINVAL;

}

static int mpu6050_remove(struct i2c_client *client)

{

struct mpu6050_data *mpu6050 = i2c_get_clientdata(client);

mpu6050_disable(mpu6050);

cancel_delayed_work(&mpu6050->work);

kfree(mpu6050);

return 0;

}

static struct i2c_device_id mpu6050_ids[] = {

{SENSOR_NAME, 0},

{ },

};

static struct i2c_driver mpu6050_driver = {

.driver = {

.name = SENSOR_NAME,

.owner = THIS_MODULE,

},

.class = I2C_CLASS_HWMON,

.id_table = mpu6050_ids,

.probe = mpu6050_probe,

.remove = mpu6050_remove,

};

/*上面定义i2c_driver结构体，整个文件的目的就是实现i2c_driver结构体，并通过module_i2c_driver

注册i2c驱动，当i2c_driver和i2c_client的name一样，系统就对其进行probe，也就是运行mpu6050_probe函数。*/

module_i2c_driver(mpu6050_driver);

查看整个驱动，实现了i2c_driver，挂载了i2c设备获得了i2c_cilent，使用了工作队列，实现数据的延时连续读取。这里分别对mpu_client.c 和mpu_driver.c进行编译得到mpu_client.ko,mpu_driver.ko。先加载mpu_client，再加载mpu_driver，得到：

可以看到驱动确实在工作，在不断获取陀螺仪数据，这里并没有将数据进行转化。