Message-ID: <20250204123925.GA3720681@ragnatech.se>
Date: Tue, 4 Feb 2025 13:39:25 +0100
From: Niklas Söderlund <niklas.soderlund@...natech.se>
To: Laurentiu Palcu <laurentiu.palcu@....nxp.com>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Sakari Ailus <sakari.ailus@...ux.intel.com>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Bartosz Golaszewski <brgl@...ev.pl>, devicetree@...r.kernel.org,
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org, linux-staging@...ts.linux.dev
Subject: Re: [RFC 00/12] staging: media: max96712: Add support for streams
 and multiple sensors

Hi Laurentiu,

Thanks for your work. I'm happy someone with a both GMSL cameras and a 
max96712 found time to work on this driver.

On 2025-01-31 18:33:54 +0200, Laurentiu Palcu wrote:
> Hi,
> 
> This series adds more functionality to the existing max96712 staging
> driver allowing multiple sensors to be connected through other
> compatible serializers. I tried to split the changes in smaller logical
> changes to make them easier to review while not altering the existing
> VPG functionality but I could squash all of them together if needed.

With this series and it's listed dependencies applied my CI tests using 
the VPG breaks. The controls to select test-pattern seems to be invalid,

    $ yavta --set-control '0x009f0903 0' /dev/v4l-subdev6
    Device /dev/v4l-subdev6 opened.
    unable to set control 0x009f0903: Permission denied (13).
    Unable to get format: Inappropriate ioctl for device (25).

    (/dev/v4l-subdev6 here is max96712 1-0049)

    $ yavta -c10 --file=/tmp/vin-capture/isp0-checkerboard-#.bin /dev/video0
    Device /dev/video0 opened.
    Device `R_Car_VIN' on `platform:e6ef0000.video' (driver 'rcar_vin') supports video, capture, without mplanes.
    Video format: ABGR32 (34325241) 1920x1080 (stride 7680) field none buffer size 8294400
    8 buffers requested.
    length: 8294400 offset: 0 timestamp type/source: mono/EoF
    Buffer 0/0 mapped at address 0xffffbe5d7000.
    length: 8294400 offset: 32768 timestamp type/source: mono/EoF
    Buffer 1/0 mapped at address 0xffffbddee000.
    length: 8294400 offset: 65536 timestamp type/source: mono/EoF
    Buffer 2/0 mapped at address 0xffffbd605000.
    length: 8294400 offset: 98304 timestamp type/source: mono/EoF
    Buffer 3/0 mapped at address 0xffffbce1c000.
    length: 8294400 offset: 131072 timestamp type/source: mono/EoF
    Buffer 4/0 mapped at address 0xffffbc633000.
    length: 8294400 offset: 163840 timestamp type/source: mono/EoF
    Buffer 5/0 mapped at address 0xffffbbe4a000.
    length: 8294400 offset: 196608 timestamp type/source: mono/EoF
    Buffer 6/0 mapped at address 0xffffbb661000.
    length: 8294400 offset: 229376 timestamp type/source: mono/EoF
    Buffer 7/0 mapped at address 0xffffbae78000.
    Unable to start streaming: Invalid argument (22).

I read in patch 12/12 "The user can also switch over to testing the test 
pattern by configuring the routes accordingly", but not how to do that 
to achieve the same functionality as the staging driver. Inspecting the 
media graph gives little help. Would it be possible to extend the cover 
letter with this information?

To be clear, I don't care about the change in behavior as this driver 
obviously primary aim should be to  support GMSL2 cameras, not 
test-pattern generation. It is important for me that it is possible to 
enable the test pattern generation $somehow at runtime (i.e. no DTS 
changes). As this is the only method I have to test a bunch of boards.

It would also be nice if the patterns generated (output frames) as 
closely as possible would resembles what is generated today. That way I 
don't have to alter my CI pipelines too much :-)

> 
> The series only supports tunneling mode and uses the first MIPI-CSI
> port. Support for more functionality can be added later, if needed.
> 
> I sent the set as a RFC because it depends on Sakari's pending internal
> pads patch which is needed if we want to have an elegant solution for
> allowing the user to switch between streaming from sensors or just
> video pattern generation.
> 
> Also, the set depends on my previous series which was not yet merged:
> https://patchwork.linuxtv.org/project/linux-media/list/?series=14255
> 
> Thanks,
> Laurentiu
> 
> Laurentiu Palcu (11):
>   dt-bindings: i2c: maxim,max96712: add a couple of new properties
>   staging: media: max96712: convert to using CCI register access helpers
>   staging: media: max96712: change DT parsing routine
>   staging: media: max96712: add link frequency V4L2 control
>   staging: media: max96712: add I2C mux support
>   staging: media: max96712: add support for streams
>   staging: media: max96712: allow enumerating MBUS codes
>   staging: media: max96712: add set_fmt routine
>   staging: media: max96712: add gpiochip functionality
>   staging: media: max96712: add fsync support
>   staging: media: max96712: allow streaming from connected sensors
> 
> Sakari Ailus (1):
>   media: mc: Add INTERNAL pad flag
> 
>  .../bindings/media/i2c/maxim,max96712.yaml    |   45 +
>  .../media/mediactl/media-types.rst            |    8 +
>  drivers/media/mc/mc-entity.c                  |   10 +-
>  drivers/staging/media/max96712/max96712.c     | 1406 +++++++++++++++--
>  include/uapi/linux/media.h                    |    1 +
>  5 files changed, 1352 insertions(+), 118 deletions(-)
> 
> -- 
> 2.44.1
> 

-- 
Kind Regards,
Niklas Söderlund

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