Re: [PATCH 1/4] docs: iio: add documentation for ad3552r driver

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 21 Mar 2025 21:28:48 +0100
Angelo Dureghello <adureghello@baylibre.com> wrote:

> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Add documentation for ad3552r driver, needed to describe the high-speed
> driver debugfs attributes and shows how the user may use them.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> ---
>  Documentation/iio/ad3552r.rst | 65 +++++++++++++++++++++++++++++++++++++++++++
>  Documentation/iio/index.rst   |  1 +
>  MAINTAINERS                   |  1 +
>  3 files changed, 67 insertions(+)
> 
> diff --git a/Documentation/iio/ad3552r.rst b/Documentation/iio/ad3552r.rst
> new file mode 100644
> index 0000000000000000000000000000000000000000..638a62c99fb876cca026a0b1df469c81ba39ff29
> --- /dev/null
> +++ b/Documentation/iio/ad3552r.rst
> @@ -0,0 +1,65 @@
> +.. SPDX-License-Identifier: GPL-2.0-only
> +
> +==============
> +AD3552R driver
> +==============
> +
> +Device driver for Analog Devices Inc. AD35XXR series of DACs. The module name
> +is ``ad3552r``.
> +With the same module name, two different driver variants are available, the
> +``generic spi`` variant, to be used with any classic SPI controllers, and the
> +``hs`` (high speed) variant, for an ADI ``axi-dac`` (IP core) based controller
> +that allows to reach the maximum sample rate supported from the DACs, using the
> +DMA transfer and all the SPI lines available (D/QDSPI)..
> +The high speed driver variant is intended to be used with the ``adi-axi-dac``
> +backend support enabled, that is enabled by default when the driver is selected.
> +
> +Supported devices
> +=================
> +
> +* `AD3541R <https://www.analog.com/en/products/ad3541r.html>`_
> +* `AD3542R <https://www.analog.com/en/products/ad3542r.html>`_
> +* `AD3551R <https://www.analog.com/en/products/ad3551r.html>`_
> +* `AD3552R <https://www.analog.com/en/products/ad3552r.html>`_
> +
> +Wiring connections
> +------------------
> +
> +::
> +
> +    .-----------------.                .-------.
> +    |                 |--- D/QSPI -----|       |
> +    |   DAC IP CORE   |--- SPI S_CLK --|  DAC  |
> +    |                 |--- SPI CS -----|       |
> +    |                 |--- LDAC -------|       |
> +    |                 |--- RESET ------|       |
> +    |_________________|                |_______|
> +
> +
> +High speed features
> +===================
> +
> +Device attributes
> +-----------------
> +
> +The following table shows the ad35xxr related device debug files, found in the
> +specific device debug folder path ``/sys/kernel/debug/iio/iio:deviceX``.
> +
> ++----------------------+-------------------------------------------------------+
> +| Debugfs device files | Description                                           |
> ++----------------------+-------------------------------------------------------+
> +| data_source          | The used data source,                                 |
> +|                      | as ``iio-buffer`` or ``backend-ramp-generator``.      |
> ++----------------------+-------------------------------------------------------+
Hmm. I'm not convinced yet that this is something that belongs in debugfs but will
read on through the series.

> +
> +Usage examples
> +--------------
> +
> +. code-block:: bash
> +	root:/sys/bus/iio/devices/iio:device0# cat data_source
> +	iio-buffer
> +	root:/sys/bus/iio/devices/iio:device0# echo -n backend-ramp-generator > data_source
> +	root:/sys/bus/iio/devices/iio:device0# cat data_source⏎

Not sure what the trailing character is.

> +	backend-ramp-generator
> +
> +
> diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst
> index bbb2edce8272e7483acca500d1a757bbcc11c1e0..2d6afc5a8ed54a90cd8d5723f0dc5212b8593d16 100644
> --- a/Documentation/iio/index.rst
> +++ b/Documentation/iio/index.rst
> @@ -19,6 +19,7 @@ Industrial I/O Kernel Drivers
>  .. toctree::
>     :maxdepth: 1
>  
> +   ad3552r
>     ad4000
>     ad4030
>     ad4695
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 57eaab00f6cb53df52a4799eb2c1afbbd1e77a1e..52bc56a9ee22c66b90555681c4757ea4399adae1 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1295,6 +1295,7 @@ L:	linux-iio@vger.kernel.org
>  S:	Supported
>  W:	https://ez.analog.com/linux-software-drivers
>  F:	Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml
> +F:	Documentation/iio/ad3552r.rst
>  F:	drivers/iio/dac/ad3552r.c
>  
>  ANALOG DEVICES INC AD4000 DRIVER
>