rtthread的sensor框架存在两个版本，其中V2版的框架号称是为了解决V1对多传感器共用一颗IC的场景支持问题而设计的（之前PR群内沟通迭代计划时提到的）。
源码解析
源码路径
components\drivers\sensor\v2\sensor.c
注册入口
/**
* Sensor mode
* rt_uint16_t mode
* 0000 | 0000 | 0000 | 0000
* unused accuracy power fetch data
*/
#define RT_SENSOR_MODE_ACCURACY_BIT_OFFSET (8)
#define RT_SENSOR_MODE_POWER_BIT_OFFSET (4)
#define RT_SENSOR_MODE_FETCH_BIT_OFFSET (0)
#define RT_SENSOR_MODE_GET_ACCURACY(mode) (rt_uint8_t)((mode >> RT_SENSOR_MODE_ACCURACY_BIT_OFFSET) & 0x0F)
#define RT_SENSOR_MODE_GET_POWER(mode) (rt_uint8_t)((mode >> RT_SENSOR_MODE_POWER_BIT_OFFSET) & 0x0F)
#define RT_SENSOR_MODE_GET_FETCH(mode) (rt_uint8_t)((mode >> RT_SENSOR_MODE_FETCH_BIT_OFFSET) & 0x0F)
#define RT_SENSOR_MODE_CLEAR_ACCURACY(mode) (mode &= ((rt_uint16_t)~((rt_uint16_t)0x0F << RT_SENSOR_MODE_ACCURACY_BIT_OFFSET)))
#define RT_SENSOR_MODE_CLEAR_POWER(mode) (mode &= ((rt_uint16_t)~((rt_uint16_t)0x0F << RT_SENSOR_MODE_POWER_BIT_OFFSET)))
#define RT_SENSOR_MODE_CLEAR_FETCH(mode) (mode &= ((rt_uint16_t)~((rt_uint16_t)0x0F << RT_SENSOR_MODE_FETCH_BIT_OFFSET)))
#define RT_SENSOR_MODE_SET_ACCURACY(mode, accuracy_mode) RT_SENSOR_MODE_CLEAR_ACCURACY(mode); (mode |= (accuracy_mode << RT_SENSOR_MODE_ACCURACY_BIT_OFFSET))
#define RT_SENSOR_MODE_SET_POWER(mode, power_mode) RT_SENSOR_MODE_CLEAR_POWER(mode); (mode |= (power_mode << RT_SENSOR_MODE_POWER_BIT_OFFSET))
#define RT_SENSOR_MODE_SET_FETCH(mode, fetch_mode) RT_SENSOR_MODE_CLEAR_FETCH(mode); (mode |= (fetch_mode << RT_SENSOR_MODE_FETCH_BIT_OFFSET))
static char *const sensor_name_str[] =
{
"None",
"ac-", /* Accelerometer */
"gy-", /* Gyroscope */
"ma-", /* Magnetometer */
"tm-", /* Temperature */
"hm-", /* Relative Humidity */
"br-", /* Barometer */
"li-", /* Ambient light */
"pr-", /* Proximity */
"hr-", /* Heart Rate */
"tv-", /* TVOC Level */
"ni-", /* Noise Loudness */
"st-", /* Step sensor */
"fr-", /* Force sensor */
"du-", /* Dust sensor */
"ec-", /* eCO2 sensor */
"gn-", /* GPS/GNSS sensor */
"tf-", /* TOF sensor */
"sp-", /* SpO2 sensor */
"ia-", /* IAQ sensor */
"et-", /* EtOH sensor */
"bp-", /* Blood Pressure */
RT_NULL
};
/* sensor local ops */
static rt_ssize_t _local_fetch_data(rt_sensor_t sensor, rt_sensor_data_t buf, rt_size_t len)
{
LOG_D("Undefined fetch_data");
return -RT_EINVAL;
}
static rt_err_t _local_control(rt_sensor_t sensor, int cmd, void *arg)
{
LOG_D("Undefined control");
return -RT_EINVAL;
}
static struct rt_sensor_ops local_ops =
{
.fetch_data = _local_fetch_data,
.control = _local_control
};
int rt_hw_sensor_register(rt_sensor_t sensor,
const char *name,
rt_uint32_t flag,
void *data)
{
rt_int8_t result;
rt_device_t device;
RT_ASSERT(sensor != RT_NULL);
char *sensor_name = RT_NULL, *device_name = RT_NULL;
if (sensor->ops == RT_NULL)
{
sensor->ops = &local_ops;
}
/* Add a type name for the sensor device */
sensor_name = sensor_name_str[sensor->info.type];
device_name = (char *)rt_calloc(1, rt_strlen(sensor_name) + 1 + rt_strlen(name));
if (device_name == RT_NULL)
{
LOG_E("device_name calloc failed!");
return -RT_ERROR;
}
rt_memcpy(device_name, sensor_name, rt_strlen(sensor_name) + 1);
strcat(device_name, name);
if (sensor->module != RT_NULL && sensor->module->lock == RT_NULL)
{
/* Create a mutex lock for the module */
sensor->module->lock = rt_mutex_create(name, RT_IPC_FLAG_PRIO);
if (sensor->module->lock == RT_NULL)
{
rt_free(device_name);
return -RT_ERROR;
}
}
device = &sensor->parent;
#ifdef RT_USING_DEVICE_OPS
device->ops = &rt_sensor_ops;
#else
device->init = RT_NULL;
device->open = _sensor_open;
device->close = _sensor_close;
device->read = _sensor_read;
device->write = RT_NULL;
device->control = _sensor_control;
#endif
device->type = RT_Device_Class_Sensor;
device->rx_indicate = RT_NULL;
device->tx_complete = RT_NULL;
device->user_data = data;
result = rt_device_register(device, device_name, flag | RT_DEVICE_FLAG_STANDALONE);
if (result != RT_EOK)
{
LOG_E("sensor[%s] register err code: %d", device_name, result);
rt_free(device_name);
return result;
}
LOG_I("sensor[%s] init success", device_name);
rt_free(device_name);
return RT_EOK;
}注册函数和v1版相比，除了名称外，几乎没有任何修改，因此可以沿用v1的分析。
打开入口
static void _sensor_cb(rt_sensor_t sen)
{
if (sen->parent.rx_indicate == RT_NULL)
{
return;
}
if (sen->irq_handle != RT_NULL)
{
sen->irq_handle(sen);
}
/* The buffer is not empty. Read the data in the buffer first */
if (sen->data_len > 0)
{
sen->parent.rx_indicate(&sen->parent, sen->data_len / sizeof(struct rt_sensor_data));
}
else if (RT_SENSOR_MODE_GET_FETCH(sen->info.mode) == RT_SENSOR_MODE_FETCH_INT)
{
/* The interrupt mode only produces one data at a time */
sen->parent.rx_indicate(&sen->parent, 1);
}
else if (RT_SENSOR_MODE_GET_FETCH(sen->info.mode) == RT_SENSOR_MODE_FETCH_FIFO)
{
sen->parent.rx_indicate(&sen->parent, sen->info.fifo_max);
}
}
static void _irq_callback(void *args)
{
rt_sensor_t sensor = (rt_sensor_t)args;
rt_uint8_t i;
if (sensor->module)
{
/* Invoke a callback for all sensors in the module */
for (i = 0; i < sensor->module->sen_num; i++)
{
_sensor_cb(sensor->module->sen[i]);
}
}
else
{
_sensor_cb(sensor);
}
}
static rt_err_t _sensor_irq_init(rt_sensor_t sensor)
{
if (sensor->config.irq_pin.pin == PIN_IRQ_PIN_NONE)
{
return -RT_EINVAL;
}
rt_pin_mode(sensor->config.irq_pin.pin, sensor->config.irq_pin.mode);
if (sensor->config.irq_pin.mode == PIN_MODE_INPUT_PULLDOWN)
{
rt_pin_attach_irq(sensor->config.irq_pin.pin, PIN_IRQ_MODE_RISING, _irq_callback, (void *)sensor);
}
else if (sensor->config.irq_pin.mode == PIN_MODE_INPUT_PULLUP)
{
rt_pin_attach_irq(sensor->config.irq_pin.pin, PIN_IRQ_MODE_FALLING, _irq_callback, (void *)sensor);
}
else if (sensor->config.irq_pin.mode == PIN_MODE_INPUT)
{
rt_pin_attach_irq(sensor->config.irq_pin.pin, PIN_IRQ_MODE_RISING_FALLING, _irq_callback, (void *)sensor);
}
rt_pin_irq_enable(sensor->config.irq_pin.pin, RT_TRUE);
LOG_I("interrupt init success");
return 0;
}
static rt_err_t _sensor_open(rt_device_t dev, rt_uint16_t oflag)
{
rt_sensor_t sensor = (rt_sensor_t)dev;
RT_ASSERT(dev != RT_NULL);
rt_err_t res = RT_EOK;
rt_err_t (*local_ctrl)(rt_sensor_t sensor, int cmd, void *arg) = _local_control;
if (sensor->module)
{
/* take the module mutex */
rt_mutex_take(sensor->module->lock, RT_WAITING_FOREVER);
}
if (sensor->module != RT_NULL && sensor->info.fifo_max > 0 && sensor->data_buf == RT_NULL)
{
/* Allocate memory for the sensor buffer */
sensor->data_buf = rt_malloc(sizeof(struct rt_sensor_data) * sensor->info.fifo_max);
if (sensor->data_buf == RT_NULL)
{
res = -RT_ENOMEM;
goto __exit;
}
}
if (sensor->ops->control != RT_NULL)
{
local_ctrl = sensor->ops->control;
}
if (oflag & RT_DEVICE_FLAG_RDONLY && dev->flag & RT_DEVICE_FLAG_RDONLY)
{
/* If polling mode is supported, configure it to polling mode */
if (local_ctrl(sensor, RT_SENSOR_CTRL_SET_FETCH_MODE, (void *)RT_SENSOR_MODE_FETCH_POLLING) == RT_EOK)
{
RT_SENSOR_MODE_SET_FETCH(sensor->info.mode, RT_SENSOR_MODE_FETCH_POLLING);
}
}
else if (oflag & RT_DEVICE_FLAG_INT_RX && dev->flag & RT_DEVICE_FLAG_INT_RX)
{
/* If interrupt mode is supported, configure it to interrupt mode */
if (local_ctrl(sensor, RT_SENSOR_CTRL_SET_FETCH_MODE, (void *)RT_SENSOR_MODE_FETCH_INT) == RT_EOK)
{
/* Initialization sensor interrupt */
_sensor_irq_init(sensor);
RT_SENSOR_MODE_SET_FETCH(sensor->info.mode, RT_SENSOR_MODE_FETCH_INT);
}
}
else if (oflag & RT_DEVICE_FLAG_FIFO_RX && dev->flag & RT_DEVICE_FLAG_FIFO_RX)
{
/* If fifo mode is supported, configure it to fifo mode */
if (local_ctrl(sensor, RT_SENSOR_CTRL_SET_FETCH_MODE, (void *)RT_SENSOR_MODE_FETCH_FIFO) == RT_EOK)
{
/* Initialization sensor interrupt */
_sensor_irq_init(sensor);
RT_SENSOR_MODE_SET_FETCH(sensor->info.mode, RT_SENSOR_MODE_FETCH_FIFO);
}
}
else
{
res = -RT_EINVAL;
goto __exit;
}
/* Configure power mode to highest mode */
if (local_ctrl(sensor, RT_SENSOR_CTRL_SET_POWER_MODE, (void *)RT_SENSOR_MODE_POWER_HIGHEST) == RT_EOK)
{
RT_SENSOR_MODE_SET_POWER(sensor->info.mode, RT_SENSOR_MODE_POWER_HIGHEST);
}
/* Configure accuracy mode to highest mode */
if (local_ctrl(sensor, RT_SENSOR_CTRL_SET_ACCURACY_MODE, (void *)RT_SENSOR_MODE_ACCURACY_HIGHEST) == RT_EOK)
{
RT_SENSOR_MODE_SET_ACCURACY(sensor->info.mode, RT_SENSOR_MODE_ACCURACY_HIGHEST);
}
__exit:
if (sensor->module)
{
/* release the module mutex */
rt_mutex_release(sensor->module->lock);
}
return res;
}和V1版本相比，主要修改点有以下部分：
a.sen->info.mode的作用范围变宽，原先8bit表示一个意思，现在时3bit表示3种功能，剩余5bit为保留位，对应的操作也改为宏的方式隐藏
b.RT_PIN_NONE 变成了 PIN_IRQ_PIN_NONE，实际功能一致，个人怀疑是版本修改漏同步了v1
c.对应驱动的RT_SENSOR_CTRL_SET_MODE入口变成了 RT_SENSOR_CTRL_SET_FETCH_MODE，对应的传递到驱动的参数也由 RT_SENSOR_MODE_xxxx 变成了 RT_SENSOR_MODE_FETCH_xxxx，实际功能未变化
d.对应驱动的 RT_SENSOR_CTRL_SET_POWER入口变成了RT_SENSOR_CTRL_SET_POWER_MODE，参数 RT_SENSOR_POWER_NORMAL 变成了 RT_SENSOR_MODE_POWER_HIGHEST，具体功能未知，需从包管理器里面找到v2版驱动对应实现才清楚
e.新增接口 RT_SENSOR_CTRL_SET_ACCURACY_MODE，具体功能未知
关闭入口
static rt_err_t _sensor_close(rt_device_t dev)
{
rt_sensor_t sensor = (rt_sensor_t)dev;
rt_err_t (*local_ctrl)(rt_sensor_t sensor, int cmd, void *arg) = _local_control;
int i;
RT_ASSERT(dev != RT_NULL);
if (sensor->module)
{
rt_mutex_take(sensor->module->lock, RT_WAITING_FOREVER);
}
if (sensor->ops->control != RT_NULL)
{
local_ctrl = sensor->ops->control;
}
/* Configure power mode to power down mode */
if (local_ctrl(sensor, RT_SENSOR_CTRL_SET_POWER_MODE, (void *)RT_SENSOR_MODE_POWER_DOWN) == RT_EOK)
{
RT_SENSOR_MODE_SET_POWER(sensor->info.mode, RT_SENSOR_MODE_POWER_DOWN);
}
if (sensor->module != RT_NULL && sensor->info.fifo_max > 0 && sensor->data_buf != RT_NULL)
{
for (i = 0; i < sensor->module->sen_num; i ++)
{
if (sensor->module->sen[i]->parent.ref_count > 0)
goto __exit;
}
/* Free memory for the sensor buffer */
for (i = 0; i < sensor->module->sen_num; i ++)
{
if (sensor->module->sen[i]->data_buf)
{
rt_free(sensor->module->sen[i]->data_buf);
sensor->module->sen[i]->data_buf = RT_NULL;
}
}
}
if (RT_SENSOR_MODE_GET_FETCH(sensor->info.mode) != RT_SENSOR_MODE_FETCH_POLLING)
{
/* Sensor disable interrupt */
if (sensor->config.irq_pin.pin != PIN_IRQ_PIN_NONE)
{
rt_pin_irq_enable(sensor->config.irq_pin.pin, RT_FALSE);
}
}
__exit:
if (sensor->module)
{
rt_mutex_release(sensor->module->lock);
}
return RT_EOK;
}相比较于打开接口，关闭接口除了改变函数名称和参数名称，并未改任何功能，因此对照v1看就可以了。
读入口
static rt_ssize_t _sensor_read(rt_device_t dev, rt_off_t pos, void *buf, rt_size_t len)
{
rt_sensor_t sensor = (rt_sensor_t)dev;
rt_size_t result = 0;
RT_ASSERT(dev != RT_NULL);
if (buf == NULL || len == 0)
{
return 0;
}
if (sensor->module)
{
rt_mutex_take(sensor->module->lock, RT_WAITING_FOREVER);
}
/* The buffer is not empty. Read the data in the buffer first */
if (sensor->data_len > 0)
{
if (len > sensor->data_len / sizeof(struct rt_sensor_data))
{
len = sensor->data_len / sizeof(struct rt_sensor_data);
}
rt_memcpy(buf, sensor->data_buf, len * sizeof(struct rt_sensor_data));
/* Clear the buffer */
sensor->data_len = 0;
result = len;
}
else
{
/* If the buffer is empty, read the data */
if (sensor->ops->fetch_data)
{
result = sensor->ops->fetch_data(sensor, buf, len);
}
}
if (sensor->module)
{
rt_mutex_release(sensor->module->lock);
}
return result;
}与关闭接口一致，读入口也没有改变任何功能，仅仅是参数名和函数名的修改。
控制入口
static rt_err_t _sensor_control(rt_device_t dev, int cmd, void *args)
{
rt_sensor_t sensor = (rt_sensor_t)dev;
rt_err_t result = RT_EOK;
RT_ASSERT(dev != RT_NULL);
rt_err_t (*local_ctrl)(rt_sensor_t sensor, int cmd, void *arg) = _local_control;
rt_uint8_t mode;
if (sensor->module)
{
rt_mutex_take(sensor->module->lock, RT_WAITING_FOREVER);
}
if (sensor->ops->control != RT_NULL)
{
local_ctrl = sensor->ops->control;
}
switch (cmd)
{
case RT_SENSOR_CTRL_GET_ID:
if (args)
{
result = local_ctrl(sensor, RT_SENSOR_CTRL_GET_ID, args);
}
break;
case RT_SENSOR_CTRL_SET_ACCURACY_MODE:
/* Configuration sensor power mode */
mode = (rt_uint32_t)args & 0x000F;
if (!(mode == RT_SENSOR_MODE_ACCURACY_HIGHEST || mode == RT_SENSOR_MODE_ACCURACY_HIGH ||\
mode == RT_SENSOR_MODE_ACCURACY_MEDIUM || mode == RT_SENSOR_MODE_ACCURACY_LOW ||\
mode == RT_SENSOR_MODE_ACCURACY_LOWEST || mode == RT_SENSOR_MODE_ACCURACY_NOTRUST))
{
LOG_E("sensor accuracy mode illegal: %d", mode);
return -RT_EINVAL;
}
result = local_ctrl(sensor, RT_SENSOR_CTRL_SET_ACCURACY_MODE, args);
if (result == RT_EOK)
{
RT_SENSOR_MODE_SET_ACCURACY(sensor->info.mode, mode);
LOG_D("set accuracy mode code: %d", RT_SENSOR_MODE_GET_ACCURACY(sensor->info.mode));
}
break;
case RT_SENSOR_CTRL_SET_POWER_MODE:
/* Configuration sensor power mode */
mode = (rt_uint32_t)args & 0x000F;
if (!(mode == RT_SENSOR_MODE_POWER_HIGHEST || mode == RT_SENSOR_MODE_POWER_HIGH ||\
mode == RT_SENSOR_MODE_POWER_MEDIUM || mode == RT_SENSOR_MODE_POWER_LOW ||\
mode == RT_SENSOR_MODE_POWER_LOWEST || mode == RT_SENSOR_MODE_POWER_DOWN))
{
LOG_E("sensor power mode illegal: %d", mode);
return -RT_EINVAL;
}
result = local_ctrl(sensor, RT_SENSOR_CTRL_SET_POWER_MODE, args);
if (result == RT_EOK)
{
RT_SENSOR_MODE_SET_POWER(sensor->info.mode, mode);
LOG_D("set power mode code: %d", RT_SENSOR_MODE_GET_POWER(sensor->info.mode));
}
break;
case RT_SENSOR_CTRL_SET_FETCH_MODE:
/* Configuration sensor power mode */
mode = (rt_uint32_t)args & 0x000F;
if (!(mode == RT_SENSOR_MODE_FETCH_POLLING || mode == RT_SENSOR_MODE_FETCH_INT ||\
mode == RT_SENSOR_MODE_FETCH_FIFO))
{
LOG_E("sensor fetch data mode illegal: %d", mode);
return -RT_EINVAL;
}
result = local_ctrl(sensor, RT_SENSOR_CTRL_SET_FETCH_MODE, args);
if (result == RT_EOK)
{
RT_SENSOR_MODE_SET_FETCH(sensor->info.mode, mode);
LOG_D("set fetch mode code: %d", RT_SENSOR_MODE_GET_FETCH(sensor->info.mode));
}
break;
case RT_SENSOR_CTRL_SELF_TEST:
/* device self test */
result = local_ctrl(sensor, RT_SENSOR_CTRL_SELF_TEST, args);
break;
case RT_SENSOR_CTRL_SOFT_RESET:
/* device soft reset */
result = local_ctrl(sensor, RT_SENSOR_CTRL_SOFT_RESET, args);
break;
default:
if (cmd > RT_SENSOR_CTRL_USER_CMD_START)
{
/* Custom commands */
result = local_ctrl(sensor, cmd, args);
}
else
{
result = -RT_EINVAL;
}
break;
}
if (sensor->module)
{
rt_mutex_release(sensor->module->lock);
}
return result;
}控制入口算是V2版框架改动最大的地方，主要修改如下：
a.去掉了入口 RT_SENSOR_CTRL_GET_INFO，其实这个入口在V1上也没啥用，仅仅是系统自带的测试命令需要的入口，而v2版改为直接处理了，不再调用一层。
b.去掉了 RT_SENSOR_CTRL_SET_RANGE 和 RT_SENSOR_CTRL_SET_ODR两个入口，这个有点无厘头，因为按我理解，其实大部分传感器都支持设置采样率和量程范围的功能，去掉这个接口，意味着只能靠驱动自己内部默认几个参数了
c.RT_SENSOR_CTRL_SET_POWER 变成了 RT_SENSOR_CTRL_SET_POWER_MODE，功能个人猜测应该没变，但需要找已经适配的代码具体确认
d.新增了 RT_SENSOR_CTRL_SET_ACCURACY_MODE入口，具体功能未知，需找已适配的代码去确认
e.新增了入口 RT_SENSOR_CTRL_SET_FETCH_MODE，具体功能为切换传感器的工作模式（中断，轮询，FIFO）
f.新增了入口 RT_SENSOR_CTRL_SOFT_RESET，从名称上感觉是软复位，是否是需看已适配的v2驱动
新增入口 -- 查找传感器设备
rt_sensor_t rt_sensor_device_find(const char *name)
{
rt_uint8_t index;
char device_name[RT_NAME_MAX];
rt_device_t device;
for (index = 0; sensor_name_str[index] != RT_NULL; index++)
{
rt_memset(device_name, 0, sizeof(device_name));
rt_snprintf(device_name, sizeof(device_name), "%s%s", sensor_name_str[index], name);
device = rt_device_find(device_name);
if (device != RT_NULL)
{
return (rt_sensor_t)device;
}
}
return RT_NULL;
}老实说，个人认为这个入口就是个坑，完全没考虑一颗芯片包含多种传感器的场景，如果不存在这种场景，可以考虑用一下这个接口，如果存在，那就不要用，很容易变成想要一个功能传感器，但拿到的是另一个功能的传感器。
总结
至此，v2版驱动已经分析完毕，相比较于v1版的驱动框架，个人认为宣传的改进不算大，相反，v2框架还去掉了一些必要的选项（量程和采样率的设置），反而限制了v2版传感器框架的使用。如果使用的话，在v2版框架成熟前，个人倾向于优先使用v1版传感器框架。事实上，如果没记错的话，去年下半年，rtt官方也默认禁用了V2版框架，个人猜测也是因为类似的原因吧。
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