Re: [PATCH 2/2] arm64: dts: imx8mp: Add overlays for ISP instances

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Hi Laurent,

Am Mittwoch, 29. November 2023, 16:16:37 CET schrieb Laurent Pinchart:
> Hi Alexander,
> 
> On Wed, Nov 29, 2023 at 11:20:07AM +0100, Alexander Stein wrote:
> > Am Mittwoch, 29. November 2023, 10:31:13 CET schrieb Paul Elder:
> > > From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > 
> > > Add two overlay to enable each ISP instance. The ISP is wired directly
> > > to the CSIS for now, bypassing the ISI completely.
> > 
> > I'm not sure if this is worth adding in a separate overlay.
> 
> The trouble is that, at this point, selection between the ISP and the
> ISI can only be performed through DT :-S That's why this is implemented
> as an overlay.

I feel a better place would be the overlay which actually adds the sensor. 
This knows best whether ISI or ISP should be used.

> > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
> > > ---
> > > 
> > >  arch/arm64/boot/dts/freescale/Makefile        |  2 ++
> > >  .../arm64/boot/dts/freescale/imx8mp-isp1.dtso | 36 +++++++++++++++++++
> > >  .../arm64/boot/dts/freescale/imx8mp-isp2.dtso | 36 +++++++++++++++++++
> > >  3 files changed, 74 insertions(+)
> > >  create mode 100644 arch/arm64/boot/dts/freescale/imx8mp-isp1.dtso
> > >  create mode 100644 arch/arm64/boot/dts/freescale/imx8mp-isp2.dtso
> > > 
> > > diff --git a/arch/arm64/boot/dts/freescale/Makefile
> > > b/arch/arm64/boot/dts/freescale/Makefile index
> > > 300049037eb0..f97dfac11189
> > > 100644
> > > --- a/arch/arm64/boot/dts/freescale/Makefile
> > > +++ b/arch/arm64/boot/dts/freescale/Makefile
> > > @@ -113,6 +113,8 @@ dtb-$(CONFIG_ARCH_MXC) += imx8mp-dhcom-pdk2.dtb
> > > 
> > >  dtb-$(CONFIG_ARCH_MXC) += imx8mp-dhcom-pdk3.dtb
> > >  dtb-$(CONFIG_ARCH_MXC) += imx8mp-evk.dtb
> > >  dtb-$(CONFIG_ARCH_MXC) += imx8mp-icore-mx8mp-edimm2.2.dtb
> > > 
> > > +dtb-$(CONFIG_ARCH_MXC) += imx8mp-isp1.dtbo
> > > +dtb-$(CONFIG_ARCH_MXC) += imx8mp-isp2.dtbo
> > > 
> > >  dtb-$(CONFIG_ARCH_MXC) += imx8mp-msc-sm2s-ep1.dtb
> > >  dtb-$(CONFIG_ARCH_MXC) += imx8mp-phyboard-pollux-rdk.dtb
> > >  dtb-$(CONFIG_ARCH_MXC) += imx8mp-tqma8mpql-mba8mpxl.dtb
> > > 
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mp-isp1.dtso
> > > b/arch/arm64/boot/dts/freescale/imx8mp-isp1.dtso new file mode 100644
> > > index 000000000000..cf394ed224ab
> > > --- /dev/null
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mp-isp1.dtso
> > > @@ -0,0 +1,36 @@
> > > +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> > > +/*
> > > + * Copyright 2022 Ideas on Board Oy
> > > + */
> > > +
> > > +/dts-v1/;
> > > +/plugin/;
> > > +
> > > +#include <dt-bindings/media/video-interfaces.h>
> > > +
> > > +&isi_0 {
> > > +	status = "disabled";
> > 
> > ISI is disabled by default. What is your intention here?
> 
> It could be enabled by an overlay for a camera module. Ideally we want
> to be able to enable both the ISI and ISP at runtime, but that's not
> possible yet and will require a very large amount of work.

Again IMHO this is part of sensor setup, in a very specific overlay. To put it 
into different words: I barely see the gain of this small overlay.

Runtime switching would require a combined media controller including both ISI 
and ISP, no?

Best regards,
Alexander

> > > +
> > > +	ports {
> > > +		port@0 {
> > > +			/delete-node/ endpoint;
> > 
> > This doesn't work in overlays. See [1]. Otherwise the OF graph connections
> > look fine to me. I'm using the same in my local overlay.
> 
> Interesting, I wasn't aware of that. Maybe we should fix it :-)
> 
> > [1]
> > https://lore.kernel.org/all/CAMuHMdWu4KZbBkvEofUV2wuA1g2S=XHHM3RUN1cNrcZB
> > khsPZA@mail.gmail.com/> 
> > > +		};
> > > +	};
> > > +};
> > > +
> > > +&isp_0 {
> > > +	status = "okay";
> > > +
> > > +	ports {
> > > +		port@1 {
> > > +			isp0_in: endpoint {
> > > +				bus-type = <MEDIA_BUS_TYPE_PARALLEL>;
> > > +				remote-endpoint = <&mipi_csi_0_out>;
> > > +			};
> > > +		};
> > > +	};
> > > +};
> > > +
> > > +&mipi_csi_0_out {
> > > +	remote-endpoint = <&isp0_in>;
> > > +};
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mp-isp2.dtso
> > > b/arch/arm64/boot/dts/freescale/imx8mp-isp2.dtso new file mode 100644
> > > index 000000000000..14e2e7b2617f
> > > --- /dev/null
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mp-isp2.dtso
> > > @@ -0,0 +1,36 @@
> > > +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> > > +/*
> > > + * Copyright 2022 Ideas on Board Oy
> > > + */
> > > +
> > > +/dts-v1/;
> > > +/plugin/;
> > > +
> > > +#include <dt-bindings/media/video-interfaces.h>
> > > +
> > > +&isi_0 {
> > > +	status = "disabled";
> > > +
> > > +	ports {
> > > +		port@1 {
> > > +			/delete-node/ endpoint;
> > > +		};
> > > +	};
> > > +};
> > > +
> > > +&isp_1 {
> > > +	status = "okay";
> > > +
> > > +	ports {
> > > +		port@1 {
> > > +			isp1_in: endpoint {
> > > +				bus-type = <MEDIA_BUS_TYPE_PARALLEL>;
> > > +				remote-endpoint = <&mipi_csi_1_out>;
> > > +			};
> > > +		};
> > > +	};
> > > +};
> > > +
> > > +&mipi_csi_1_out {
> > > +	remote-endpoint = <&isp1_in>;
> > > +};


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