iio: ina2xx: add ABI documentation entry sysfs-bus-iio-ina2xx-adc

Documentation for attributes:

 * in_allow_async_readout
 * in_shunt_resistor

Signed-off-by: Marc Titinger <mtitinger@baylibre.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-ina2xx-adc b/Documentation/ABI/testing/sysfs-bus-iio-ina2xx-adc
new file mode 100644 (file)
index 0000000..8916f7e
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-ina2xx-adc
@@ -0,0 +1,24 @@
+What:          /sys/bus/iio/devices/iio:deviceX/in_allow_async_readout
+Date:          December 2015
+KernelVersion: 4.4
+Contact:       linux-iio@vger.kernel.org
+Description:
+               By default (value '0'), the capture thread checks for the Conversion
+               Ready Flag to being set prior to committing a new value to the sample
+               buffer. This synchronizes the in-chip conversion rate with the
+               in-driver readout rate at the cost of an additional register read.
+
+               Writing '1' will remove the polling for the Conversion Ready Flags to
+               save the additional i2c transaction, which will improve the bandwidth
+               available for reading data. However, samples can be occasionally skipped
+               or repeated, depending on the beat between the capture and conversion
+               rates.
+
+What:          /sys/bus/iio/devices/iio:deviceX/in_shunt_resistor
+Date:          December 2015
+KernelVersion: 4.4
+Contact:       linux-iio@vger.kernel.org
+Description:
+               The value of the shunt resistor may be known only at runtime fom an
+               eeprom content read by a client application. This attribute allows to
+               set its value in ohms.