#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。