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/* sensor.h - public sensor driver API */
/*
* Copyright (c) 2016 Intel Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __SENSOR_H__
#define __SENSOR_H__
/**
* @brief Sensor Interface
* @defgroup sensor_interface Sensor Interface
* @ingroup io_interfaces
* @{
*/
#ifdef __cplusplus
extern "C" {
#endif
#include <stdint.h>
#include <device.h>
#include <errno.h>
#ifdef CONFIG_SENSOR_WORKQUEUE
#include <misc/nano_work.h>
#endif
/** @brief Sensor value types. */
enum sensor_value_type {
/** val1 contains an integer value, val2 is unused. */
SENSOR_VALUE_TYPE_INT,
/**
* val1 contains an integer value, val2 is the fractional value.
* To obtain the final value, use the formula: val1 + val2 *
* 10^(-6).
*/
SENSOR_VALUE_TYPE_INT_PLUS_MICRO,
/**
* @brief val1 contains a Q16.16 representation, val2 is
* unused.
*/
SENSOR_VALUE_TYPE_Q16_16,
/** @brief dval contains a floating point value. */
SENSOR_VALUE_TYPE_DOUBLE,
};
/**
* @brief Representation of a sensor readout value.
*
* The meaning of the fields is dictated by the type field.
*/
struct sensor_value {
enum sensor_value_type type;
union {
struct {
int32_t val1;
int32_t val2;
};
double dval;
};
};
/**
* @brief Sensor channels.
*/
enum sensor_channel {
/** Acceleration on the X axis, in m/s^2. */
SENSOR_CHAN_ACCEL_X,
/** Acceleration on the Y axis, in m/s^2. */
SENSOR_CHAN_ACCEL_Y,
/** Acceleration on the Z axis, in m/s^2. */
SENSOR_CHAN_ACCEL_Z,
/** Acceleration on any axis. */
SENSOR_CHAN_ACCEL_ANY,
/** Angular velocity around the X axis, in radians/s. */
SENSOR_CHAN_GYRO_X,
/** Angular velocity around the Y axis, in radians/s. */
SENSOR_CHAN_GYRO_Y,
/** Angular velocity around the Z axis, in radians/s. */
SENSOR_CHAN_GYRO_Z,
/** Angular velocity on any axis. */
SENSOR_CHAN_GYRO_ANY,
/** Magnetic field on the X axis, in Gauss. */
SENSOR_CHAN_MAGN_X,
/** Magnetic field on the Y axis, in Gauss. */
SENSOR_CHAN_MAGN_Y,
/** Magnetic field on the Z axis, in Gauss. */
SENSOR_CHAN_MAGN_Z,
/** Magnetic field on any axis. */
SENSOR_CHAN_MAGN_ANY,
/** Temperature in degrees Celsius. */
SENSOR_CHAN_TEMP,
/** Pressure in kilopascal. */
SENSOR_CHAN_PRESS,
/**
* Proximity. Adimensional. A value of 1 indicates that an
* object is close.
*/
SENSOR_CHAN_PROX,
/** Humidity, in milli percent. */
SENSOR_CHAN_HUMIDITY,
/** Illuminance in visible spectrum, in lux. */
SENSOR_CHAN_LIGHT,
/** Illuminance in infra-red spectrum, in lux. */
SENSOR_CHAN_IR,
/** Altitude, in meters */
SENSOR_CHAN_ALTITUDE,
/** All channels. */
SENSOR_CHAN_ALL,
};
/**
* @brief Sensor trigger types.
*/
enum sensor_trigger_type {
/**
* Timer-based trigger, useful when the sensor does not have an
* interrupt line.
*/
SENSOR_TRIG_TIMER,
/** Trigger fires whenever new data is ready. */
SENSOR_TRIG_DATA_READY,
/**
* Trigger fires when the selected channel varies significantly.
* This includes any-motion detection when the channel is
* acceleration or gyro. If detection is based on slope between
* successive channel readings, the slope threshold is configured
* via the @ref SENSOR_ATTR_SLOPE_TH and @ref SENSOR_ATTR_SLOPE_DUR
* attributes.
*/
SENSOR_TRIG_DELTA,
/** Trigger fires when a near/far event is detected. */
SENSOR_TRIG_NEAR_FAR,
/**
* Trigger fires when channel reading transitions configured
* thresholds. The thresholds are configured via the @ref
* SENSOR_ATTR_LOWER_THRESH and @ref SENSOR_ATTR_UPPER_THRESH
* attributes.
*/
SENSOR_TRIG_THRESHOLD,
};
/**
* @brief Sensor trigger spec.
*/
struct sensor_trigger {
/** Trigger type. */
enum sensor_trigger_type type;
/** Channel the trigger is set on. */
enum sensor_channel chan;
};
/**
* @brief Sensor attribute types.
*/
enum sensor_attribute {
/**
* Sensor sampling frequency, i.e. how many times a second the
* sensor takes a measurement.
*/
SENSOR_ATTR_SAMPLING_FREQUENCY,
/** Lower threshold for trigger. */
SENSOR_ATTR_LOWER_THRESH,
/** Upper threshold for trigger. */
SENSOR_ATTR_UPPER_THRESH,
/** Threshold for any-motion (slope) trigger. */
SENSOR_ATTR_SLOPE_TH,
/**
* Duration for which the slope values needs to be
* outside the threshold for the trigger to fire.
*/
SENSOR_ATTR_SLOPE_DUR,
/** Oversampling factor */
SENSOR_ATTR_OVERSAMPLING,
/** Sensor range, in SI units. */
SENSOR_ATTR_FULL_SCALE,
/**
* The sensor value returned will be altered by the amount indicated by
* offset: final_value = sensor_value + offset.
*/
SENSOR_ATTR_OFFSET,
/**
* Calibration target. This will be used by the internal chip's
* algorithms to calibrate itself on a certain axis, or all of them.
*/
SENSOR_ATTR_CALIB_TARGET,
};
typedef void (*sensor_trigger_handler_t)(struct device *dev,
struct sensor_trigger *trigger);
typedef int (*sensor_attr_set_t)(struct device *dev,
enum sensor_channel chan,
enum sensor_attribute attr,
const struct sensor_value *val);
typedef int (*sensor_trigger_set_t)(struct device *dev,
const struct sensor_trigger *trig,
sensor_trigger_handler_t handler);
typedef int (*sensor_sample_fetch_t)(struct device *dev,
enum sensor_channel chan);
typedef int (*sensor_channel_get_t)(struct device *dev,
enum sensor_channel chan,
struct sensor_value *val);
struct sensor_driver_api {
sensor_attr_set_t attr_set;
sensor_trigger_set_t trigger_set;
sensor_sample_fetch_t sample_fetch;
sensor_channel_get_t channel_get;
};
/**
* @brief Set an attribute for a sensor
*
* @param dev Pointer to the sensor device
* @param chan The channel the attribute belongs to, if any. Some
* attributes may only be set for all channels of a device, depending on
* device capabilities.
* @param attr The attribute to set
* @param val The value to set the attribute to
*
* @return 0 if successful, negative errno code if failure.
*/
static inline int sensor_attr_set(struct device *dev,
enum sensor_channel chan,
enum sensor_attribute attr,
const struct sensor_value *val)
{
struct sensor_driver_api *api;
api = (struct sensor_driver_api *)dev->driver_api;
if (!api->attr_set) {
return -ENOTSUP;
}
return api->attr_set(dev, chan, attr, val);
}
/**
* @brief Activate a sensor's trigger and set the trigger handler
*
* The handler will be called from a fiber, so I2C or SPI operations are
* safe. However, the fiber's stack is limited and defined by the
* driver. It is currently up to the caller to ensure that the handler
* does not overflow the stack.
*
* @param dev Pointer to the sensor device
* @param trig The trigger to activate
* @param handler The function that should be called when the trigger
* fires
*
* @return 0 if successful, negative errno code if failure.
*/
static inline int sensor_trigger_set(struct device *dev,
struct sensor_trigger *trig,
sensor_trigger_handler_t handler)
{
struct sensor_driver_api *api;
api = (struct sensor_driver_api *)dev->driver_api;
if (!api->trigger_set) {
return -ENOTSUP;
}
return api->trigger_set(dev, trig, handler);
}
/**
* @brief Fetch a sample from the sensor and store it in an internal
* driver buffer
*
* Read all of a sensor's active channels and, if necessary, perform any
* additional operations necessary to make the values useful. The user
* may then get individual channel values by calling @ref
* sensor_channel_get.
*
* Since the function communicates with the sensor device, it is unsafe
* to call it in an ISR if the device is connected via I2C or SPI.
*
* @param dev Pointer to the sensor device
*
* @return 0 if successful, negative errno code if failure.
*/
static inline int sensor_sample_fetch(struct device *dev)
{
struct sensor_driver_api *api;
api = (struct sensor_driver_api *)dev->driver_api;
return api->sample_fetch(dev, SENSOR_CHAN_ALL);
}
/**
* @brief Fetch a sample from the sensor and store it in an internal
* driver buffer
*
* Read and compute compensation for one type of sensor data (magnetometer,
* accelerometer, etc). The user may then get individual channel values by
* calling @ref sensor_channel_get.
*
* This is mostly implemented by multi function devices enabling reading at
* different sampling rates.
*
* Since the function communicates with the sensor device, it is unsafe
* to call it in an ISR if the device is connected via I2C or SPI.
*
* @param dev Pointer to the sensor device
* @param chan The channel that needs updated
*
* @return 0 if successful, negative errno code if failure.
*/
static inline int sensor_sample_fetch_chan(struct device *dev,
enum sensor_channel type)
{
struct sensor_driver_api *api;
api = (struct sensor_driver_api *)dev->driver_api;
return api->sample_fetch(dev, type);
}
/**
* @brief Get a reading from a sensor device
*
* Return a useful value for a particular channel, from the driver's
* internal data. Before calling this function, a sample must be
* obtained by calling @ref sensor_sample_fetch or
* @ref sensor_sample_fetch_chan. It is guaranteed that two subsequent
* calls of this function for the same channels will yield the same
* value, if @ref sensor_sample_fetch or @ref sensor_sample_fetch_chan
* has not been called in the meantime.
*
* For vectorial data samples you can request all axes in just one call
* by passing the specific channel with _ANY suffix. The sample will be
* returned at val[0], val[1] and val[2] (X, Y and Z in that order).
*
* @param dev Pointer to the sensor device
* @param chan The channel to read
* @param val Where to store the value
*
* @return 0 if successful, negative errno code if failure.
*/
static inline int sensor_channel_get(struct device *dev,
enum sensor_channel chan,
struct sensor_value *val)
{
struct sensor_driver_api *api;
api = (struct sensor_driver_api *)dev->driver_api;
return api->channel_get(dev, chan, val);
}
/**
* @brief The value of gravitational constant in micro m/s^2.
*/
#define SENSOR_G 9806650LL
/**
* @brief The value of constant PI in micros.
*/
#define SENSOR_PI 3141592LL
/**
* @brief Helper function to convert acceleration from m/s^2 to Gs
*
* @param ms2 A pointer to a sensor_value struct holding the acceleration,
* in m/s^2.
*
* @return The converted value, in Gs.
*/
static inline int32_t sensor_ms2_to_g(const struct sensor_value *ms2)
{
int64_t micro_ms2 = ms2->val1 * 1000000LL + ms2->val2;
if (micro_ms2 > 0) {
return (micro_ms2 + SENSOR_G / 2) / SENSOR_G;
} else {
return (micro_ms2 - SENSOR_G / 2) / SENSOR_G;
}
}
/**
* @brief Helper function to convert acceleration from Gs to m/s^2
*
* @param g The G value to be converted.
* @param ms2 A pointer to a sensor_value struct, where the result is stored.
*/
static inline void sensor_g_to_ms2(int32_t g, struct sensor_value *ms2)
{
ms2->type = SENSOR_VALUE_TYPE_INT_PLUS_MICRO;
ms2->val1 = ((int64_t)g * SENSOR_G) / 1000000LL;
ms2->val2 = ((int64_t)g * SENSOR_G) % 1000000LL;
}
/**
* @brief Helper function for converting radians to degrees.
*
* @param rad A pointer to a sensor_value struct, holding the value in radians.
*
* @return The converted value, in degrees.
*/
static inline int32_t sensor_rad_to_degrees(const struct sensor_value *rad)
{
int64_t micro_rad_s = rad->val1 * 1000000LL + rad->val2;
if (micro_rad_s > 0) {
return (micro_rad_s * 180LL + SENSOR_PI / 2) / SENSOR_PI;
} else {
return (micro_rad_s * 180LL - SENSOR_PI / 2) / SENSOR_PI;
}
}
/**
* @brief Helper function for converting degrees to radians.
*
* @param d The value (in degrees) to be converted.
* @param rad A pointer to a sensor_value struct, where the result is stored.
*/
static inline void sensor_degrees_to_rad(int32_t d, struct sensor_value *rad)
{
rad->type = SENSOR_VALUE_TYPE_INT_PLUS_MICRO;
rad->val1 = ((int64_t)d * SENSOR_PI / 180LL) / 1000000LL;
rad->val2 = ((int64_t)d * SENSOR_PI / 180LL) % 1000000LL;
}
#ifdef __cplusplus
}
#endif
/**
* @}
*/
#endif /* __SENSOR_H__ */