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

[Angelo Dureghello]

Hi Marcelo,

On 26.03.2025 19:28, Marcelo Schmitt wrote:
> The doc seems to be all about the high-speed setup despite classical SPI support
> being mentioned. It would be interesting to see how the regular SPI and hs
> ad3552r IIO devices differ from each other (wiring connections, IIO device
> interfaces (attributes, debug files, ...), any other relevant peculiarities).
> Some comments about that inline.
> 

had to add this file mainly to describe ramp generator usage.

The ad3552r (classic SPI) is quite old stuff, may work with whatever
controller with classic simple SPI (SDI/SDO/S_CLK/CS) so no particular
wiring diagram or explainations should be needed. 

> On 03/21, Angelo Dureghello wrote:
> > From: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
> > 
> > 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@xxxxxxxxxxxx>
> > ---
> ...
> > +==============
> > +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)..
> Is D/QDSPI about dual and quad SPI? If so, what about saying that more clearly? 
> 
> > +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 ------|       |
> > +    |_________________|                |_______|
> 
> This only describes how the HDL IP connects to the DAC which is the high speed
> use case. Maybe add a diagram for the regular SPI connection wiring or say that
> the above is only for the hs setup?
> Also, what about adding a link to the HDL documentation page?
> https://analogdevicesinc.github.io/hdl/projects/ad35xxr_evb/index.html
> 
> > +
> > +
> > +High speed features
> > +===================
> > +
> > +Device attributes
> > +-----------------
> This is only describing the debugfs file. What about also listing the usual
> IIO device channels and attributes (out_voltageX_raw, out_voltageX_en, ...)?
> 

they are already documented, since part of the iio stuff.
Please see Documentation/ABI/testing/sysfs-bus-iio.

> > +
> > +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``.      |
> > ++----------------------+-------------------------------------------------------+
> > +

Reagrds,
angelo