drivers/sensors: add initial support for fixed-point data for sensors

new sensor framework can now select between float data type and
fixed-point data type

Signed-off-by: raiden00pl <raiden00@railab.me>

Documentation/components/drivers/special/sensors/sensors_uorb.rst

@@ -48,11 +48,68 @@ sensor events are sent to the ring buffer in the upper layer.
    :width: 800px
    :align: center
 
-Problems to solve
-=================
+Sensor data type
+================
 
-The current implementation uses the ``float`` type which may make it difficult
-to use on platforms without FPU support.
+The framework supports two types of sensor data:
+
+#. ``float`` if ``CONFIG_SENSORS_USE_FLOAT=y``, not recommended for
+   targets without FPU.
+
+#. ``b16_t`` if ``CONFIG_SENSORS_USE_B16=y``, recommended for targets without
+   FPU.
+
+Currently all sensors support ``float``, support for ``b16_t`` is work-in-progress.
+
+.. warning::
+
+   Using fixed-point math instead of floating point may cause sensors measurements
+   to saturate where they wouldn't before. Verify that fixed-point data types are
+   sufficient for your application. Just because a driver has fixed-point support
+   **does not mean** it can support the sensor's full range.
+
+To create generic drivers that support both data types, you should use the dedicated
+sensor data type:
+
+.. code:: C
+
+   /* Data type for sensors */
+
+   #ifdef CONFIG_SENSORS_USE_B16
+   typedef b16_t sensor_data_t;
+   #else
+   typedef float sensor_data_t;
+   #endif
+
+Mathematical operations on this type should only be performed using dedicated
+macros:
+
+- ``sensor_data_ftof(f1)`` - convert float to sensor data number.
+  Should be used only for compile-time constants.
+
+- ``sensor_data_itof(i)`` - convert int to sensor data number.
+
+- ``sensor_data_inv(i)`` - invert int and convert to sensor data number
+
+- ``sensor_data_add(f1, f2)`` - add two sensor data numbers
+
+- ``sensor_data_sub(f1, f2)`` - subtract two sensor data numbers
+
+- ``sensor_data_subi(f1, i)`` - subtract int from sensor data number
+
+- ``sensor_data_mul(f1, f2)`` - multiply two sensor data numbers
+
+- ``sensor_data_muli(f1, i)`` - multiply sensor data with int
+
+- ``sensor_data_div(f1, f2)`` - divide two sensor data numbers
+
+- ``sensor_data_divi(f1, i)`` - divide sensor data with int
+
+- ``sensor_data_abs(f1)`` - get absolute value for sensor data number
+
+- ``sensor_data_sqrt(f1)`` - get sqrt for sensro data number
+
+- ``sensor_data_usat(f1)`` - unsigned saturation for sensor data.
 
 **Code**
 ========
@@ -313,9 +370,9 @@ being ``sensor_device_info_s``.
   struct sensor_device_info_s
   {
     uint32_t      version;
-    float         power;
-    float         max_range;
-    float         resolution;
+    sensor_data_t power;
+    sensor_data_t max_range;
+    sensor_data_t resolution;
     int32_t       min_delay;
     int32_t       max_delay;
     uint32_t      fifo_reserved_event_count;

drivers/sensors/Kconfig

@@ -17,6 +17,24 @@ config USENSOR
 	---help---
 		Allow application to register user sensor by /dev/usensor.
 
+choice
+	prompt "Sensor framework data type"
+	default SENSORS_USE_FLOAT
+
+config SENSORS_USE_FLOAT
+	bool "Use float as data type for sensors"
+	---help---
+		Use float as data type for sensors.
+		This option is recommended for targets with FPU support.
+
+config SENSORS_USE_B16
+	bool "Use b16_t as data type for sensors"
+	---help---
+		Use b16_t (fixed-point type) as data type for sensors.
+		This option is recommended for targets without FPU support.
+
+endchoice # Sensor framework data type
+
 config SENSORS_RPMSG
 	bool "Sensor RPMSG Support"
 	default n

drivers/sensors/adxl362_uorb.c

@@ -43,6 +43,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define ADXL362_SPI_FREQUENCY         1000000
 #define ADXL362_SPI_MODE              SPIDEV_MODE0
 

drivers/sensors/bme680_uorb.c

@@ -49,6 +49,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define BME680_ADDR 0x76 /* I2C Slave Address */
 #define BME680_FREQ CONFIG_BME680_I2C_FREQUENCY
 #define BME680_DEVID 0x61

drivers/sensors/bme688_uorb.c

@@ -49,6 +49,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define BME688_ADDR                0x76 /* I2C Slave Address */
 #define BME688_FREQ                CONFIG_BME688_I2C_FREQUENCY
 #define BME688_DEVID               0x61

drivers/sensors/bmi088_uorb.c

@@ -36,6 +36,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define BMI088_DEFAULT_INTERVAL 10000  /* Default conversion interval. */
 
 /****************************************************************************

drivers/sensors/bmi160_uorb.c

@@ -36,6 +36,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define BMI160_DEFAULT_INTERVAL 10000  /* Default conversion interval. */
 
 /****************************************************************************

drivers/sensors/bmi270_uorb.c

@@ -49,6 +49,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define CONSTANTS_ONE_G 9.8f
 
 /****************************************************************************

drivers/sensors/bmm150_uorb.c

@@ -43,6 +43,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define BMM150_CHIPID_VAL        0x32
 
 #define BMM150_CHIPID            0x40

drivers/sensors/bmp180_uorb.c

@@ -37,6 +37,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define BMP180_MIN_INTERVAL 30000
 
 /****************************************************************************

drivers/sensors/bmp280_uorb.c

@@ -45,6 +45,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #ifdef  CONFIG_BMP280_I2C_ADDR_76
 #define BMP280_ADDR         0x76
 #else

drivers/sensors/ds18b20_uorb.c

@@ -50,6 +50,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #ifndef CONFIG_ENDIAN_BIG
 #  define ds18b20_leuint64(x) (x)
 #endif

drivers/sensors/fakesensor_uorb.c

@@ -46,6 +46,16 @@
 #include <nuttx/sensors/gnss.h>
 #endif
 
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 /****************************************************************************
  * Private Types
  ****************************************************************************/

drivers/sensors/fs3000_uorb.c

@@ -45,6 +45,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define FS3000_ADDR           0x28
 
 /****************************************************************************

drivers/sensors/gnss_uorb.c

@@ -43,6 +43,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define GNSS_PATH_FMT          "/dev/ttyGNSS%d"
 
 #define GNSS_PARSE_BUFFERSIZE  256

drivers/sensors/goldfish_gnss_uorb.c

@@ -40,6 +40,16 @@
 #include <nuttx/sensors/goldfish_gnss.h>
 #include <nuttx/sensors/gnss.h>
 
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 /****************************************************************************
  * Private Types
  ****************************************************************************/

drivers/sensors/goldfish_sensor_uorb.c

@@ -45,6 +45,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define GOLDFISH_LIST_SENSOR_CMD "list-sensors"
 
 /****************************************************************************

drivers/sensors/hyt271_uorb.c

@@ -47,6 +47,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define HYT271_TEMPDATA_MASK 0x3fff
 #define HYT271_HUMIDATA_MASK 0x3fff
 

drivers/sensors/l3gd20_uorb.c

@@ -46,6 +46,16 @@
 
 #if defined(CONFIG_SPI) && defined(CONFIG_SENSORS_L3GD20)
 
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 /****************************************************************************
  * Private Types
  ****************************************************************************/

drivers/sensors/l86xxx_uorb.c

@@ -58,6 +58,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #ifndef CONFIG_SENSORS_L86_XXX_THREAD_STACKSIZE
 #define CONFIG_SENSORS_L86_XXX_THREAD_STACKSIZE 10000
 #endif

drivers/sensors/lis2mdl_uorb.c

@@ -49,6 +49,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 /* The value that should be in the "who am I" register */
 
 #define WHO_AM_I_VAL 0x40

drivers/sensors/lsm6dso32_uorb.c

@@ -46,6 +46,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 /* The value that should be in the WHO_AM_I register. */
 
 #define WHO_AM_I_VAL 0x6c

drivers/sensors/lsm9ds1_uorb.c

@@ -49,6 +49,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define CONSTANTS_ONE_G 9.8f
 
 /****************************************************************************

drivers/sensors/ltr308_uorb.c

@@ -45,6 +45,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define LTR308_ADDR           0x53
 #define DEVID                 0xB1
 

drivers/sensors/mcp9600_uorb.c

@@ -47,6 +47,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define REG_THERMO_HOT_JUNC 0x0 /* Thermocouple Hot-Junction, T H */
 #define REG_JUNC_TEMP_DELTA 0x1 /* Junctions Temperature Delta, TΔ */
 #define REG_COLD_JUNC_TEMP 0x2  /* Cold-Junction Temperature, T C */

drivers/sensors/mpu9250_uorb.c

@@ -51,6 +51,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define  MPU9250_AKM_DEV_ID                 0x48  /* Magnetometer device ID */
 #define  MIN(x, y)         (x) > (y) ? (y) : (x)
 

drivers/sensors/ms56xx_uorb.c

@@ -52,6 +52,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define MS56XX_CMD_RESET              0x1e
 #define MS56XX_CMD_START_ADC_READ     0x00
 #define MS56XX_CMD_CONV_D1_OSR_256    0x40 /* D1 = uncompensated pressure */

drivers/sensors/sht4x_uorb.c

@@ -47,6 +47,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define SHT4X_CRC_INIT 0xFF /* Initial value of the calculated CRC. */
 #define SHT4X_CRC_POLY 0x31 /* CRC calculation polynomial. */
 

drivers/sensors/wtgahrs2_uorb.c

@@ -43,6 +43,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Only float data type supported now */
+
+#ifdef CONFIG_SENSORS_USE_B16
+#  error fixed-point data type not supported yet
+#endif
+
 #define WTGAHRS2_ACCEL_IDX         0
 #define WTGAHRS2_GYRO_IDX          1
 #define WTGAHRS2_MAG_IDX           2