There are already humidity sensors in the hwmon subsystem,
so we use their unit (milli percent) here as well.
Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
For some devices it is possible to configure a hysteresis for threshold (or
similar) events. This patch adds a new hysteresis event info type which allows
for easy creation and read/write handling of the sysfs attribute.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
The documentation says that the result of raw * scale should be in microvolts,
but in reallity all drivers actually report the scale so that the result is in
millivolts. So update the documentation to match reallity.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Integration time is in seconds; it controls the measurement
time and influences the gain of a sensor.
There are two typical ways that scaling is implemented in a device:
1) input amplifier,
2) reference to the ADC is changed.
These both result in the accuracy of the ADC varying (by applying its
sampling over a more relevant range).
Integration time is a way of dealing with noise inherent in the analog
sensor itself. In the case of a light sensor, a mixture of photon noise
and device specific noise. Photon noise is dealt with by either improving
the efficiency of the sensor, (more photons actually captured) which is not
easily varied dynamically, or by integrating the measurement over a longer
time period. Note that this can also be thought of as an averaging of a
number of individual samples and is infact sometimes implemented this way.
Altering integration time implies that the duration of a measurement changes,
a fact the device's user may be interested in.
Hence it makes sense to distinguish between integration time and simple
scale. In some devices both types of control are present and whilst they
will have similar effects on the amplitude of the reading, their effect
on the noise of the measurements will differ considerably.
Used by adjd_s311, tsl4531, tcs3472
The following drivers have similar controls (and could be adapted):
* tsl2563 (integration time is controlled via CALIBSCALE among other things)
* tsl2583 (has integration_time device_attr, but driver doesn't use channels yet)
* tsl2x7x (has integration_time attr)
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Jon Brenner <jon.brenner@ams.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Add description about in_accelX_power_mode and
in_accel_power_mode_available.
Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
update ABI documentation with current paths related to scan_elements folder
Paths changed long time ago in commit: 26d25ae3f0
Signed-off-by: Alexandre Relange <alexandre@relange.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This patch adds support for a new IIO channel type for pressure measurements.
This can for example be used for barometric pressure sensors.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
We need this for the pstore fixes that went into the staging-linus branch, so
that things apply properly for the pstore/android code merge.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
v2: address comments by Jonathan Cameron
* add more output power down modes
* spelling of etc.
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Continuous frequency/clock generating devices, such as DDSs or PLLs
should use out_altvoltage.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This file contains only the most generic elements. Other
class specific and device specific ABI documents will follow
over time.
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
