diff options
Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-iio')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-iio | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio index e3df71987eff..df42bed09f25 100644 --- a/Documentation/ABI/testing/sysfs-bus-iio +++ b/Documentation/ABI/testing/sysfs-bus-iio @@ -15,6 +15,7 @@ Description: based on hardware generated events (e.g. data ready) or provided by a separate driver for other hardware (e.g. periodic timer, GPIO or high resolution timer). + Contains trigger type specific elements. These do not generalize well and hence are not documented in this file. X is the IIO index of the trigger. @@ -666,6 +667,7 @@ Description: <type>[Y][_name]_<raw|input>_thresh_falling_value may take different values, but the device can only enable both thresholds or neither. + Note the driver will assume the last p events requested are to be enabled where p is how many it supports (which may vary depending on the exact set requested. So if you want to be @@ -720,6 +722,7 @@ Description: <type>[Y][_name]_<raw|input>_roc_falling_value may take different values, but the device can only enable both rate of change thresholds or neither. + Note the driver will assume the last p events requested are to be enabled where p is however many it supports (which may vary depending on the exact set requested. So if you want to be @@ -775,9 +778,11 @@ Description: Specifies the value of threshold that the device is comparing against for the events enabled by <type>Y[_name]_thresh[_rising|falling]_en. + If separate attributes exist for the two directions, but direction is not specified for this attribute, then a single threshold value applies to both directions. + The raw or input element of the name indicates whether the value is in raw device units or in processed units (as _raw and _input do on sysfs direct channel read attributes). @@ -860,6 +865,7 @@ Description: If separate attributes exist for the two directions, but direction is not specified for this attribute, then a single hysteresis value applies to both directions. + For falling events the hysteresis is added to the _value attribute for this event to get the upper threshold for when the event goes back to normal, for rising events the hysteresis is subtracted from the _value @@ -906,6 +912,7 @@ Description: Specifies the value of rate of change threshold that the device is comparing against for the events enabled by <type>[Y][_name]_roc[_rising|falling]_en. + If separate attributes exist for the two directions, but direction is not specified for this attribute, then a single threshold value applies to both directions. @@ -1305,6 +1312,7 @@ Description: Proximity measurement indicating that some object is near the sensor, usually by observing reflectivity of infrared or ultrasound emitted. + Often these sensors are unit less and as such conversion to SI units is not possible. Higher proximity measurements indicate closer objects, and vice versa. Units after @@ -1450,9 +1458,12 @@ Contact: linux-iio@vger.kernel.org Description: A single positive integer specifying the maximum number of scan elements to wait for. + Poll will block until the watermark is reached. + Blocking read will wait until the minimum between the requested read amount or the low water mark is available. + Non-blocking read will retrieve the available samples from the buffer even if there are less samples then watermark level. This allows the application to block on poll with a timeout and read @@ -1481,11 +1492,13 @@ Description: device settings allows it (e.g. if a trigger is set that samples data differently that the hardware fifo does then hardware fifo will not enabled). + If the hardware fifo is enabled and the level of the hardware fifo reaches the hardware fifo watermark level the device will flush its hardware fifo to the device buffer. Doing a non blocking read on the device when no samples are present in the device buffer will also force a flush. + When the hardware fifo is enabled there is no need to use a trigger to use buffer mode since the watermark settings guarantees that the hardware fifo is flushed to the device @@ -1523,6 +1536,7 @@ Description: A single positive integer specifying the minimum watermark level for the hardware fifo of this device. If the device does not have a hardware fifo this entry is not present. + If the user sets buffer/watermark to a value less than this one, then the hardware watermark will remain unset. @@ -1533,6 +1547,7 @@ Description: A single positive integer specifying the maximum watermark level for the hardware fifo of this device. If the device does not have a hardware fifo this entry is not present. + If the user sets buffer/watermark to a value greater than this one, then the hardware watermark will be capped at this value. @@ -1544,6 +1559,7 @@ Description: levels for the hardware fifo. This entry is optional and if it is not present it means that all the values between hwfifo_watermark_min and hwfifo_watermark_max are supported. + If the user sets buffer/watermark to a value greater than hwfifo_watermak_min but not equal to any of the values in this list, the driver will chose an appropriate value for the @@ -1605,7 +1621,8 @@ KernelVersion: 4.1.0 Contact: linux-iio@vger.kernel.org Description: '1' (enable) or '0' (disable) specifying the enable - of heater function. Same reading values apply + of heater function. Same reading values apply. + This ABI is especially applicable for humidity sensors to heatup the device and get rid of any condensation in some humidity environment |