Some datasheets use a different unit to specify the channel scale than what IIO
expects it to be. This patch adds two helper macros which allow to convert units
commonly used in datasheets to IIO units:
* acceleration: g -> meter / second**2
* angular velocity: degree (/ second) -> rad (/ second)
This makes it much more convenient to specify and also easier to verify a
channel's scale attribute.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Add a function to read a processed value from a channel. The function will first
attempt to read the IIO_CHAN_INFO_PROCESSED attribute. If that fails it will
read the IIO_CHAN_INFO_RAW attribute and convert the result from a raw value to
a processed value.
The patch also introduces a function to convert raw value to a processed value
and exports it, in case a user needs or wants to do the conversion by itself.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
For the iio_read_channel_raw and iio_read_channel_scale the kerneldoc comment
refers to an argument called "channel", while the argument is called "chan" in
the function signature. This leads to the following warnings from kerneldoc:
Warning(include/linux/iio/consumer.h:71): No description found for parameter 'chan'
Warning(include/linux/iio/consumer.h:71): Excess function parameter 'channel' description in 'iio_read_channel_raw'
Warning(include/linux/iio/consumer.h:109): No description found for parameter 'chan'
Warning(include/linux/iio/consumer.h:109): Excess function parameter 'channel' description in 'iio_read_channel_scale'
This patch fixes the warnings by naming them consistently.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Currently IIO uses a decimal fixed point representations for real type numbers.
This patch introduces a new representation for rational type numbers. The number
will be expressed by specifying a numerator and denominator. For converting a
raw value to a processed value multiply it by the numerator and divide it by the
denominator.
The reasoning for introducing this new type is that for a lot of devices the
scale can be represented easily by a fractional number, but it is not possible
to represent it as fixed point number without rounding. E.g. for a simple DAC
the scale is often the reference voltage divided by the number of possible
values (Usually 2**n_bits - 1). Each driver currently implements the conversion
of this fraction to a fixed point number on its own.
Also when it comes to the in-kernel interface this allows to directly use the
fractional factors to convert a raw value to a processed value. This should on
one hand require less instructions and on the other hand increase the
precision.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Drop timestamp parameter from buffer store_to callback and subsequently from
iio_push_to_buffer. The timestamp parameter is unused and it seems likely that
it will stay unused in the future, so it should be safe to remove it.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Added hysteresis to the list of channel info enumeration, shared
/separate bit defines and to postfix channel info strings.
Signed-off-by: srinivas pandruvada <srinivas.pandruvada@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Add includes and forward declarations for types used in this file. This avoids
compile errors if the other files have not been included before.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Add include guards to the IIO headers where they are missing. This avoids
compile errors due to redefined types if a file is included more than once.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
The symbol name for the #ifndef and the #define of the include guard do not
match and thus it becomes quite ineffective. Add the missing '_' to fix this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Most devices from the Analog Devices Sigma Delta family use a similar scheme for
communication with the device. This includes register access, as well as trigger
handling. But each device sub-family has different features and different
register layouts (some even have no registers at all) and thus it is impractical
to try to support all of the devices by the same driver. This patch adds a
common base library for Sigma Delta converter devices. It will be used by
individual drivers.
This code is mostly based on the three existing Sigma Delta drivers the AD7192,
AD7780 and AD7793, but has been improved for more robustness and flexibility.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Introduce two new helper functions to attach a arbitrary pointer to a IIO
device. This is useful to get access to external non-global data from within a
IIO device callbacks where only the IIO device is available.
Internally these functions use dev_{set,get}_drvdata() on the struct device
embedded in the IIO device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
With small channel spacing values and high reference frequencies it is
possible to exceed the range of the 10-bit counter.
Workaround by checking the range and widening some constrains.
We don't use the REG1_PHASE value in this case the datasheet recommends to set
it to 1 if not used.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Add iio channel type and modifiers for Correlated Color Temperature (CCT)
and RGBC (red/green/blue/clear) data.
Add CCT and RGBC descriptions to documentation.
Changes:
Revised/condensed RGBC descriptions.
Merge and trivial fix done by Jonathan Cameron.
Signed-off-by: Jon Brenner <jbrenner@taosinc.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Add a helper function for validating a scan mask for devices where exactly one
channel must be selected during sampling. This is a common case among devices
which have scan mask restrictions so it makes sense to provide this function in
the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This is useful for cases where the number of valid scan masks grows
exponentially, but it is rather easy to check whether a mask is valid or not
programmatically.
An example of such a case is a device with multiple ADCs where each ADC has a
upstream MUX, which allows to select from a number of physical channels.
+-------+ +-------+
| | | | --- Channel 1
| ADC 1 |---| MUX 1 | --- ...
| | | | --- Channel M
+-------+ +-------+
. . .
. . .
. . .
+-------+ +-------+
| | | | --- Channel M * N + 1
| ADC N |---| MUX N | --- ...
| | | | --- Channel M * N + M
+-------+ +-------+
The number of necessary scan masks for this case is (M+1)**N - 1, on the other
hand it is easy to check whether subsets for each ADC of the scanmask have only
one bit set.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
There will probably be a number of such modifiers eventually but
this one is used in the adis16240 accelerometer driver.
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
There will probably be a number of such modifiers eventually but
this one is used in the adis16204 accelerometer driver.
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
These were originally introduced when the plan was to have parallel
IIO cores in and out of staging with a slow move between them.
Now we have reached the point where the whole core has moved,
they need clearing up!
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
