Re: [PATCH v2 1/2] ALSA: docs: Add Marian M2 driver documentation

[Jonathan Corbet <corbet@lwn.net>]

Ivan Orlov <ivan.orlov0322@gmail.com> writes:

> Add documentation for the new MARIAN Seraph M2 sound card. It covers
> current development status, available controls of the card and
> information about the integrated loopback.
>
> Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
> ---
> V1 -> V2:
> - Remove redundant documentation fix from the next patch in the series

One quick comment below...

>  Documentation/sound/cards/index.rst     |   1 +
>  Documentation/sound/cards/marian-m2.rst | 104 ++++++++++++++++++++++++
>  2 files changed, 105 insertions(+)
>  create mode 100644 Documentation/sound/cards/marian-m2.rst
>
> diff --git a/Documentation/sound/cards/index.rst b/Documentation/sound/cards/index.rst
> index e68bbb13c384..e873592d8d00 100644
> --- a/Documentation/sound/cards/index.rst
> +++ b/Documentation/sound/cards/index.rst
> @@ -19,3 +19,4 @@ Card-Specific Information
>     serial-u16550
>     img-spdif-in
>     pcmtest
> +   marian-m2
> diff --git a/Documentation/sound/cards/marian-m2.rst b/Documentation/sound/cards/marian-m2.rst
> new file mode 100644
> index 000000000000..bf12445e20d7
> --- /dev/null
> +++ b/Documentation/sound/cards/marian-m2.rst
> @@ -0,0 +1,104 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=======================
> +MARIAN Seraph M2 Driver
> +=======================
> +
> +Sep 18, 2023
> +
> +Ivan Orlov <ivan.orlov0322@gmail.com>
> +
> +STATE OF DEVELOPMENT
> +====================
> +
> +This driver is based on the driver written by Florian Faber in 2012, which seemed to work fine.
> +However, the initial code contained multiple issues, which had to be solved before sending the
> +driver upstream.

Sticking to the 80-column limit is best for documentation, especially
when there is no reason to go over it.

> +The vendor lost the full documentation, so what we have here was recovered from drafts and found
> +after experiments with the card.
> +
> +What seems to be working fine:
> +- Playback and capture for all supported rates
> +- Integrated loopback (with some exceptions, see below)
> +
> +MEMORY MODEL
> +============
> +
> +The hardware requires one huge contiguous DMA space to be allocated. After allocation, the bus address of
> +this buffer should be written to the hardware register.
> +
> +We can split this space into two parts: the first one contains samples for capture, another one contains
> +play samples:
> +
> +CAPTURE_CH_0, CAPTURE_CH_1, ..., CAPTURE_CH_127 | PLAY_CH_0, PLAY_CH_1, ..., PLAY_CH_127

You should really use literal blocks for this (and a lot that follows)
or it won't render the way you want in HTML.  The simplest way to do
that is to use a double colon ("...samples::") and to indent the literal
text.

(OK, two comments, sorry about the off-by-one...:)

Thanks,

jon