Re: [RFC PATCH v10 6/9] media: tegra: Add Tegra210 Video input driver

From: Sowjanya Komatineni
Date: Sat Apr 25 2020 - 22:19:41 EST



On 4/25/20 7:10 PM, Dmitry Osipenko wrote:
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26.04.2020 04:43, Sowjanya Komatineni ÐÐÑÐÑ:
...
It looks to me that at least all those hardcoded HW format IDs do not
match the older SoCs.
TPG hard coded formats are supported on prior Tegra.

Other supported formats are SoC dependent and part of soc data in the
driver already.
But I don't see where that SoC-dependent definition is made in
terga210.c. That tegra_image_format enum looks T210-specific, isn't it?

...

Video formats which are SoC variants are made soc specific in driver already tegra_vi_soc structure member video_formats

tegra_image_format enum is same for T210 and T186

For T194, enums will be diff and will have diff TEGRA194_VIDEO_FORMAT using corresponding Tegra194 video format enums

The driver will need to have a bit better separation if it's supposed to
have a common core for all SoCs. Each incompatible VI/CSI hardware
version should have its own kernel module.
currently other Tegra host1x driver (drm) also does similar. Single
module for all Tegra SoCs.
DRM driver has a proper separation of the sub-drivers where sub-driver
won't load on unsupported hardware. The tegra-video driver should do the
same, i.e. VI and CSI should be individual drivers (and not OPS). There
could be a some common core, but for now it's not obvious to me what
that core should be, maybe just the video.c.

With current tegra-video, all the v4l2 related common part of
implementation is same for all tegra's and only
tegra210.c/tegra186.c/tegra194.c will have corresponding tegra soc
specific vi/csi programming sequence.
This code shouldn't be shared within the same driver module, IMO.


The tegra-video should be okay, although the "video" part sounds a bit
too broad since video could mean a lot of things. I think downstream
kernel uses (or at least used) the tegra-camera name for the driver,
perhaps it could be a reasonable variant as well.
prior feedback suggests not to use camera variant instead to use video
Alright, then the tegra-video should be fine.