This adds a new page to document how to use the ad7380 ADC driver. Credit: this docs is based on ad7944 docs. Signed-off-by: Julien Stephan <jstephan@xxxxxxxxxxxx> --- This commit adds documentation page for ad738x ADC family --- Documentation/iio/ad7380.rst | 88 ++++++++++++++++++++++++++++++++++++++++++++ Documentation/iio/index.rst | 1 + MAINTAINERS | 1 + 3 files changed, 90 insertions(+) diff --git a/Documentation/iio/ad7380.rst b/Documentation/iio/ad7380.rst new file mode 100644 index 000000000000..061cd632b5df --- /dev/null +++ b/Documentation/iio/ad7380.rst @@ -0,0 +1,88 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============= +AD7380 driver +============= + +ADC driver for Analog Devices Inc. AD7380 and similar devices. The module name +is ``ad7380``. + + +Supported devices +================= + +The following chips are supported by this driver: + +* `AD7380 <https://www.analog.com/en/products/ad7380.html>`_ +* `AD7381 <https://www.analog.com/en/products/ad7381.html>`_ +* `AD7383 <https://www.analog.com/en/products/ad7383.html>`_ +* `AD7384 <https://www.analog.com/en/products/ad7384.html>`_ +* `AD7380-4 <https://www.analog.com/en/products/ad7380-4.html>`_ +* `AD7381-4 <https://www.analog.com/en/products/ad7381-4.html>`_ +* `AD7383-4 <https://www.analog.com/en/products/ad7383-4.html>`_ +* `AD7384-4 <https://www.analog.com/en/products/ad7384-4.html>`_ + + +Supported features +================== + +SPI wiring modes +---------------- + +ad738x ADCs can output data on several SDO lines (1/2/4). The driver currently +supports only 1 SDO line. + +Reference voltage +----------------- + +2 possible reference voltage sources are supported: + +- Internal reference (2.5V) +- External reference (2.5V to 3.3V) + +The source is determined by the device tree. If ``refio-supply`` is present, +then the external reference is used, else the internal reference is used. + +Oversampling and resolution boost +--------------------------------- + +This family supports 2 types of oversampling: normal average and rolling +average. Only normal average is supported by the driver, as rolling average can +be achieved by processing a captured data buffer. The following ratios are +available: 1 (oversampling disabled)/2/4/8/16/32. + +When the on-chip oversampling function is enabled the performance of the ADC can +exceed the default resolution. To accommodate the performance boost achievable, +it is possible to enable an additional two bits of resolution. Because the +resolution boost feature can only be enabled when oversampling is enabled and +oversampling is not as useful without the resolution boost, the driver +automatically enables the resolution boost if and only if oversampling is +enabled. + +Since the resolution boost feature causes 16-bit chips to now have 18-bit data +which means the storagebits has to change from 16 to 32 bits, we use the new +ext_scan_type feature to allow changing the scan_type at runtime. Unfortunately +libiio does not support it. So when enabling or disabling oversampling, user +must restart iiod using the following command: + +.. code-block:: bash + + root:~# systemctl restart iiod + + +Unimplemented features +---------------------- + +- 2/4 SDO lines +- Rolling average oversampling +- Power down mode +- CRC indication +- Alert + + +Device buffers +============== + +This driver supports IIO triggered buffers. + +See :doc:`iio_devbuf` for more information. diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst index 9cb4c50cb20d..b0385a9ee5a7 100644 --- a/Documentation/iio/index.rst +++ b/Documentation/iio/index.rst @@ -18,6 +18,7 @@ Industrial I/O Kernel Drivers .. toctree:: :maxdepth: 1 + ad7380 ad7944 adis16475 adis16480 diff --git a/MAINTAINERS b/MAINTAINERS index 06ecfa64a39a..40cf58c2f884 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -447,6 +447,7 @@ S: Supported W: https://wiki.analog.com/resources/tools-software/linux-drivers/iio-adc/ad738x W: https://ez.analog.com/linux-software-drivers F: Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml +F: Documentation/iio/ad7380.rst F: drivers/iio/adc/ad7380.c AD7877 TOUCHSCREEN DRIVER --- base-commit: 986da024b99a72e64f6bdb3f3f0e52af024b1f50 change-id: 20240708-ad7380-add-docs-42a9296e5cd3 Best regards, -- Julien Stephan <jstephan@xxxxxxxxxxxx>
