[PATCH v1 5/5] ARM: tegra: add MIPI calibration binding for Tegra20/Tegra30

[Svyatoslav Ryhel]

пт, 18 лип. 2025 р. о 12:01 Mikko Perttunen <mperttunen at nvidia.com> пише:
>
> On Thursday, July 17, 2025 11:21 PM Svyatoslav Ryhel wrote:
> > Add MIPI calibration device node for Tegra20 and Tegra30.
> >
> > Signed-off-by: Svyatoslav Ryhel <clamor95 at gmail.com>
> > ---
> >  arch/arm/boot/dts/nvidia/tegra20.dtsi | 14 ++++++++++++++
> >  arch/arm/boot/dts/nvidia/tegra30.dtsi | 18 ++++++++++++++++++
> >  2 files changed, 32 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/nvidia/tegra20.dtsi
> > b/arch/arm/boot/dts/nvidia/tegra20.dtsi index 92d422f83ea4..521261045cc8
> > 100644
> > --- a/arch/arm/boot/dts/nvidia/tegra20.dtsi
> > +++ b/arch/arm/boot/dts/nvidia/tegra20.dtsi
> > @@ -74,6 +74,16 @@ vi at 54080000 {
> >                       status = "disabled";
> >               };
> >
> > +             /* DSI MIPI calibration logic is a part of VI/CSI */
> > +             mipi: mipi at 54080220 {
> > +                     compatible = "nvidia,tegra20-mipi";
> > +                     reg = <0x54080220 0x100>;
> > +                     clocks = <&tegra_car TEGRA20_CLK_VI>,
> > +                              <&tegra_car TEGRA20_CLK_CSI>;
> > +                     clock-names = "vi", "csi";
> > +                     #nvidia,mipi-calibrate-cells = <1>;
> > +             };
> > +
>
> As you say in the comment, MIPI calibration on Tegra20/30 is part of VI/CSI.
> We can't add a "mipi" device here since such a device doesn't exist in the
> hardware hierarchy. We already have the VI device in the device tree, so we
> need to use that.

I understand your point, but embedding MIPI calibration logic into
VI/CSI driver will bring up another lever of unnecessary complexity
and excessive coding. While approach I have proposed preserves
separation between CSI and DSI and reuses already existing MIPI
calibration framework.

>
> A driver for tegra20-vi already exists in staging/drivers/media/tegra-video.
> We should aim not to break it. Perhaps bring it out of staging? (At least
> partially, but then why not the whole thing.)

It does not break VI/CSI, I have a WIP CSI implementation for
Tegra20/Tegra30 which I hope to submit soon.

>
> Thanks,
> Mikko
>
>
>
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