On Fri, 24 Feb 2023 15:02:32 +0200 Matti Vaittinen <mazziesaccount@xxxxxxxxx> wrote: > For occasional contributor like me navigating the IIO channel types and > modifiers may be a daunting task. One may have hard time finding out > what type of channel should be used for device data and what units the > data should be converted. > > There is a great documentation for the sysfs interfaces though. What is > missing is mapping of the channel types and modifiers to the sysfs > documentation (and entries in documentation). > > Give a hand to a driver writer by providing some documentation and by > pointing to the sysfs document from the kerneldocs of respective enums. > > Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx> +CC linux-iio > --- > Please note that this RFC patch should not be applied as is. The docs > have TODO comments regarding units for IIO_ELECTRICALCONDUCTIVITY, > IIO_PHASE and IIO_RESISTANCE. I'll fix these TODOs, remove RFC and respin > if anyone familiar with the values provided via sysfs could provide me the > corret units for these channels. I am also open to any suggestions how > to better link from enum documentation to specific entry at the IIO sysfs > documetation. > > Initial discussion about these docs can be found from: > https://lore.kernel.org/all/0e0d45b7-e582-82b2-9bac-1f70f9dad9f7@xxxxxxxxx/ > --- > include/uapi/linux/iio/types.h | 140 ++++++++++++++++++++++++++++++++- > 1 file changed, 139 insertions(+), 1 deletion(-) > > diff --git a/include/uapi/linux/iio/types.h b/include/uapi/linux/iio/types.h > index c79f2f046a0b..e6329d3cc055 100644 > --- a/include/uapi/linux/iio/types.h > +++ b/include/uapi/linux/iio/types.h > @@ -10,7 +10,129 @@ > > #ifndef _UAPI_IIO_TYPES_H_ > #define _UAPI_IIO_TYPES_H_ > - > +/** > + * iio_chan_type - Type of data transferred via IIO channel. > + * > + * The 'main' type of data transferred via channel. Please note that most > + * devices need to specify also a more accurate 'sub category'. See the > + * enum iio_modifier for this. (For example, IIO_ACCEL channel often needs to > + * specify the direction. IIO_CONCENTRATION specifies the type of substance > + * it measures etc). > + * > + * Use of correct units is required but scale and offset that user must apply > + * to channel values can be advertised. > + * > + * Please find the detailed documentation for reported values from the > + * Documentation/ABI/testing/sysfs-bus-iio. > + * > + * IIO_ACCEL: Acceleration, m/s^2 > + * Doc keyword: in_accel_x_raw > + * > + * IIO_ACTIVITY: Activity state. For example a pedometer signaling > + * jogging, walking or staying still. > + * Doc keyword: in_activity_still_thresh_rising_en > + * > + * IIO_ALTVOLTAGE: > + * > + * IIO_ANGL: Angle of rotation, radians. > + * Doc keyword: in_angl_raw > + * > + * IIO_ANGL_VEL: Angular velocity, rad/s > + * Doc keyword: in_anglvel_x_raw > + * > + * IIO_CAPACITANCE: Capacitance, nanofarads. > + * Doc keyword: in_capacitanceY_raw > + * > + * IIO_CCT: > + * > + * IIO_CURRENT: Current, milliamps > + * Doc keyword: in_currentY_raw > + * > + * IIO_CONCENTRATION: Reading of a substance, percents. Used for example by > + * deviced measuring amount of CO2, O2, ethanol... > + * Doc keyword: in_concentration_raw > + * > + * IIO_COUNT: Deprecated, please use counter subsystem. > + * > + * IIO_DISTANCE: Distance in meters. Typically used to report measured > + * distance to an object or the distance covered by the > + * user > + * Doc keyword: in_distance_input > + * > + * IIO_ELECTRICALCONDUCTIVITY: electric conductivity, siemens per meter > + * Doc keyword: in_electricalconductivity_raw > + * TODO: What does "can be processed to siemens per meter" > + * mean? Do we have unit requirement? > + * > + * IIO_ENERGY: Energy in Joules. Typically reported by a device > + * measuring energy burnt by the user. > + * Doc keyword: in_energy_input > + * > + * IIO_GRAVITY: Gravity, m/s^2 > + * Doc keyword: in_gravity_x_raw > + * > + * IIO_HUMIDITYRELATIVE: Relative humidity, percents > + * Doc keyword: in_humidityrelative_raw > + * > + * IIO_INCLI: Inclination, degrees > + * Doc keyword: in_incli_x_raw > + * > + * IIO_INDEX: Deprecated, please use Counter subsystem > + * > + * IIO_INTENSITY: Unitless intensity. > + * Doc keyword: in_intensityY_raw > + * > + * IIO_LIGHT: Visible light intensity, lux > + * Doc keyword: in_illuminance_raw > + * > + * IIO_MAGN: Magnetic field, Gauss. > + * Doc keyword: in_magn_x_raw > + * > + * IIO_MASSCONCENTRATION: Mass concentration, ug / m3 > + * Doc keyword: in_massconcentration_pm1_input > + * > + * IIO_PH: pH reading, negative base-10 logarithm of hydrodium > + * ions in a litre of water > + * Doc keyword: in_ph_raw > + * > + * IIO_PHASE: Phase difference, radians > + * Doc keyword: in_phaseY_raw > + * TODO: What does "can be processed to radians" mean? Do > + * we have unit requirement? > + * > + * IIO_POSITIONRELATIVE: Relative position. > + * Doc keyword: in_positionrelative_x_raw > + * > + * IIO_POWER: Power, milliwatts > + * Doc keyword: in_powerY_raw > + * > + * IIO_PRESSURE: Pressure, kilopascal > + * Doc keyword: in_pressureY_raw > + * > + * IIO_RESISTANCE: Resistance, ohms > + * Doc keyword: in_resistance_raw > + * TODO: What means "can be processed..." Do we have unit > + * requirement? > + * > + * IIO_ROT: Euler angles, deg > + * Doc keyword: in_rot_yaw_raw > + * > + * IIO_STEPS: Steps taken by the user > + * Doc keyword: in_steps_input > + * > + * IIO_TEMP: Temperature, milli degrees Celsius > + * Doc keyword: in_temp_raw > + * > + * IIO_UVINDEX: UV light intensity index > + * Doc keyword: in_uvindex_input > + * > + * IIO_VELOCITY: Current speed (norm or magnitude of the velocity > + * vector), m/s > + * Doc keyword: in_velocity_sqrt(x^2+y^2+z^2)_input > + * > + * IIO_VOLTAGE: Voltage, millivolts > + * Doc keyword: in_voltageY_raw > + */ > enum iio_chan_type { > IIO_VOLTAGE, > IIO_CURRENT, > @@ -49,6 +171,22 @@ enum iio_chan_type { > IIO_MASSCONCENTRATION, > }; > > +/** > + * iio_modifier - accurate class for channel data > + * > + * IIO_MOD_<X,Y,Z>: Value represents <X,Y,Z>-axis data. > + * Typically used by channels of type: > + * IIO_ACCEL, IIO_TEMP, IIO_GRAVITY, IIO_POSITIONRELATIVE, > + * IIO_ANGL_VEL, IIO_INCLI, IIO_MAGN > + * IIO_MOD_LIGHT_BOTH: Value contains visible and infra red light components > + * IIO_MOD_LIGHT_IR: Value represents infra-red radiation > + * IIO_MOD_LIGHT_<RED, GREEN, BLUE>: > + * Value represents visible <red, green, blue> light > + * IIO_MOD_LIGHT_CLEAR: Value represents all visible light frequencies > + * > + * Please find the detailed documentation for reported values from the > + * Documentation/ABI/testing/sysfs-bus-iio. > + */ > enum iio_modifier { > IIO_NO_MOD, > IIO_MOD_X, > > base-commit: c9c3395d5e3dcc6daee66c6908354d47bf98cb0c
