RE: [Patch v6] dt-bindings: media: s5p-mfc: convert bindings to json-schema

["Aakarsh Jain" <aakarsh.jain@samsung.com>]

> -----Original Message-----
> From: Krzysztof Kozlowski [mailto:krzysztof.kozlowski@linaro.org]
> Sent: 02 March 2023 14:07
> To: Aakarsh Jain <aakarsh.jain@samsung.com>; linux-arm-
> kernel@lists.infradead.org; linux-media@vger.kernel.org; linux-
> kernel@vger.kernel.org; devicetree@vger.kernel.org
> Cc: m.szyprowski@samsung.com; andrzej.hajda@intel.com;
> mchehab@kernel.org; hverkuil-cisco@xs4all.nl;
> ezequiel@vanguardiasur.com.ar; jernej.skrabec@gmail.com;
> benjamin.gaignard@collabora.com; krzysztof.kozlowski+dt@linaro.org;
> stanimir.varbanov@linaro.org; dillon.minfei@gmail.com;
> david.plowman@raspberrypi.com; mark.rutland@arm.com;
> robh+dt@kernel.org; krzk+dt@kernel.org; andi@etezian.org;
> alim.akhtar@samsung.com; aswani.reddy@samsung.com;
> pankaj.dubey@samsung.com
> Subject: Re: [Patch v6] dt-bindings: media: s5p-mfc: convert bindings to json-
> schema
> 
> On 01/03/2023 04:51, Aakarsh Jain wrote:
> > Convert s5p-mfc bindings to DT schema format using json-schema.
> >
> > Signed-off-by: Aakarsh Jain <aakarsh.jain@samsung.com>
> > ---
> > changes since v5:
> > kept compatible strings under enum
> > sorted compatible strings
> > added iommu maxItems:2
> > Added indentation with 4 spaces in dts example
> >
> > changes since v4:
> > Removed items from oneOf section
> > dropped black line
> > defined the iommus names items as
> > items:
> > -const left
> > -const right
> >
> > changes since v3:
> > fixed dt-schema warnings and errors while running make dtbs_check and
> > make dt_binding_check for ARMv7 Since, obsolete properties are not part
> of dt-node so we are not including these properties in dt-schema.
> >
> > changes since v2:
> > changed Commit message from Adds to Convert Removed text "This file
> > has moved to samsung,s5p-mfc.yaml" from s5p-mfc.txt fixed dt-schema
> > warnings and errors while running make dtbs_check and make
> > dt_binding_check
> >
> > changes since v1:
> > fixed dt-schema warnings and errors while running make dtbs_check and
> > make dt_binding_check Removed description.
> > Listed items.
> > Added allOf:if:then for restricting two items to specific compatible
> >
> > This patch is independent from the previous MFC v12 patch series for HW3
> support.
> >
> >  .../devicetree/bindings/media/s5p-mfc.txt     |  78 ---------
> >  .../bindings/media/samsung,s5p-mfc.yaml       | 151
> ++++++++++++++++++
> >  2 files changed, 151 insertions(+), 78 deletions(-)  create mode
> > 100644 Documentation/devicetree/bindings/media/samsung,s5p-mfc.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/media/s5p-mfc.txt
> > b/Documentation/devicetree/bindings/media/s5p-mfc.txt
> > index 8eb90c043d5d..e69de29bb2d1 100644
> > --- a/Documentation/devicetree/bindings/media/s5p-mfc.txt
> > +++ b/Documentation/devicetree/bindings/media/s5p-mfc.txt
> > @@ -1,78 +0,0 @@
> > -* Samsung Multi Format Codec (MFC)
> > -
> > -Multi Format Codec (MFC) is the IP present in Samsung SoCs which
> > -supports high resolution decoding and encoding functionalities.
> > -The MFC device driver is a v4l2 driver which can encode/decode -video
> > raw/elementary streams and has support for all popular -video codecs.
> > -
> > -Required properties:
> > -  - compatible : value should be either one among the following
> > -	(a) "samsung,mfc-v5" for MFC v5 present in Exynos4 SoCs
> > -	(b) "samsung,mfc-v6" for MFC v6 present in Exynos5 SoCs
> > -	(c) "samsung,exynos3250-mfc", "samsung,mfc-v7" for MFC v7
> > -	     present in Exynos3250 SoC
> > -	(d) "samsung,mfc-v7" for MFC v7 present in Exynos5420 SoC
> > -	(e) "samsung,mfc-v8" for MFC v8 present in Exynos5800 SoC
> > -	(f) "samsung,exynos5433-mfc" for MFC v8 present in Exynos5433 SoC
> > -	(g) "samsung,mfc-v10" for MFC v10 present in Exynos7880 SoC
> > -
> > -  - reg : Physical base address of the IP registers and length of memory
> > -	  mapped region.
> > -
> > -  - interrupts : MFC interrupt number to the CPU.
> > -  - clocks : from common clock binding: handle to mfc clock.
> > -  - clock-names : from common clock binding: must contain "mfc",
> > -		  corresponding to entry in the clocks property.
> > -
> > -Optional properties:
> > -  - power-domains : power-domain property defined with a phandle
> > -			   to respective power domain.
> > -  - memory-region : from reserved memory binding: phandles to two
> reserved
> > -	memory regions, first is for "left" mfc memory bus interfaces,
> > -	second if for the "right" mfc memory bus, used when no SYSMMU
> > -	support is available; used only by MFC v5 present in Exynos4 SoCs
> > -
> > -Obsolete properties:
> > -  - samsung,mfc-r, samsung,mfc-l : support removed, please use memory-
> region
> > -	property instead
> > -
> > -
> > -Example:
> > -SoC specific DT entry:
> > -
> > -mfc: codec@13400000 {
> > -	compatible = "samsung,mfc-v5";
> > -	reg = <0x13400000 0x10000>;
> > -	interrupts = <0 94 0>;
> > -	power-domains = <&pd_mfc>;
> > -	clocks = <&clock 273>;
> > -	clock-names = "mfc";
> > -};
> > -
> > -Reserved memory specific DT entry for given board (see reserved
> > memory binding -for more information):
> > -
> > -reserved-memory {
> > -	#address-cells = <1>;
> > -	#size-cells = <1>;
> > -	ranges;
> > -
> > -	mfc_left: region@51000000 {
> > -		compatible = "shared-dma-pool";
> > -		no-map;
> > -		reg = <0x51000000 0x800000>;
> > -	};
> > -
> > -	mfc_right: region@43000000 {
> > -		compatible = "shared-dma-pool";
> > -		no-map;
> > -		reg = <0x43000000 0x800000>;
> > -	};
> > -};
> > -
> > -Board specific DT entry:
> > -
> > -codec@13400000 {
> > -	memory-region = <&mfc_left>, <&mfc_right>;
> > -};
> > diff --git
> > a/Documentation/devicetree/bindings/media/samsung,s5p-mfc.yaml
> > b/Documentation/devicetree/bindings/media/samsung,s5p-mfc.yaml
> > index 000000000000..da48d0493cdd
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/samsung,s5p-mfc.yaml
> > @@ -0,0 +1,151 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause %YAML 1.2
> > +---
> > +$id:
> > +https://protect2.fireeye.com/v1/url?k=d24ef7e4-8dd5cefd-d24f7cab-
> 000b
> > +abff3793-d3511b88da8176a3&q=1&e=3ebd99e2-81bd-4303-988b-
> 085ab2449cc1&
> >
> +u=http%3A%2F%2Fdevicetree.org%2Fschemas%2Fmedia%2Fsamsung%2Cs
> 5p-mfc.y
> > +aml%23
> > +$schema:
> > +https://protect2.fireeye.com/v1/url?k=5aeac908-0571f011-5aeb4247-
> 000b
> > +abff3793-01e9fec8ce4d48cc&q=1&e=3ebd99e2-81bd-4303-988b-
> 085ab2449cc1&
> > +u=http%3A%2F%2Fdevicetree.org%2Fmeta-schemas%2Fcore.yaml%23
> > +
> > +title: Samsung Exynos Multi Format Codec (MFC)
> > +
> > +maintainers:
> > +  - Marek Szyprowski <m.szyprowski@samsung.com>
> > +  - Aakarsh Jain <aakarsh.jain@samsung.com>
> > +
> > +description:
> > +  Multi Format Codec (MFC) is the IP present in Samsung SoCs which
> > +  supports high resolution decoding and encoding functionalities.
> > +
> > +properties:
> > +  compatible:
> > +    oneOf:
> > +      - enum:
> > +          - samsung,exynos5433-mfc        # Exynos5433
> > +          - samsung,mfc-v5                # Exynos4
> > +          - samsung,mfc-v6                # Exynos5
> > +          - samsung,mfc-v7                # Exynos5420
> > +          - samsung,mfc-v8                # Exynos5800
> > +          - samsung,mfc-v10               # Exynos7880
> > +      - items:
> > +          - enum:
> > +              - samsung,exynos3250-mfc    # Exynos3250
> > +          - const: samsung,mfc-v7         # Fall back for Exynos3250
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    minItems: 1
> > +    maxItems: 3
> > +
> > +  clock-names:
> > +    minItems: 1
> > +    maxItems: 3
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  iommus:
> > +    minItems: 1
> > +    maxItems: 2
> > +
> > +  iommu-names:
> > +    items:
> > +      - const: left
> > +      - const: right
> 
> That's confusing now... The iommu-names above says it requires two
> iommus, but your iommus property says one item is enough. You need here
> minItems: 1... but then why one IOMMU (for such variants) is always "left"?
> Probably then the meaning of first IOMMU changes, right? If that's correct,
> then I propose to leave it as minItems:1/maxItems:2 without defining the
> items here and...
> 
Agreed. That’s why I initially kept  as minItems:1/maxItems:2.  Will keep it now as it is.
  iommu-names:
    minItems: 1
    maxItems: 2
> > +
> > +  power-domains:
> > +    maxItems: 1
> > +
> > +  memory-region:
> > +    minItems: 1
> > +    maxItems: 2
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - clocks
> > +  - clock-names
> > +  - interrupts
> > +
> > +additionalProperties: false
> > +
> > +allOf:
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - samsung,mfc-v5
> > +              - samsung,exynos3250-mfc
> > +    then:
> > +      properties:
> > +        clocks:
> > +          maxItems: 2
> > +        clock-names:
> > +          items:
> > +            - const: mfc
> > +            - const: sclk_mfc
> 
> iommus:
>   maxItems: 1
> iommu-names: false
> 
I am getting compilation errors with above property set and its breaking the bindings.
If we see these two nodes in dtsi files.
               mfc: codec@13400000 {
                        compatible = "samsung,mfc-v5";
..
                        iommus = <&sysmmu_mfc_l>, <&sysmmu_mfc_r>;
                        iommu-names = "left", "right";
}
And 
              mfc: codec@13400000 {
                        compatible = "samsung,exynos3250-mfc", "samsung,mfc-v7";
                        reg = <0x13400000 0x10000>;
...
                        iommus = <&sysmmu_mfc>;
                };
There is no iommu-names property for compatible "samsung,exynos3250-mfc, samsung,mfc-v7", that’s why I kept
        iommus:
          minItems: 1
          maxItems: 2
I would even go with below if you agree?
        iommus:
          minItems: 1
          maxItems: 2
        iommus-names: false

> > +
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - samsung,mfc-v6
> > +              - samsung,mfc-v8
> > +    then:
> > +      properties:
> > +        clocks:
> > +          maxItems: 1
> > +        clock-names:
> > +          items:
> > +            - const: mfc
> > +        iommus:
> > +          maxItems: 2
> 
> ... and here:
> iommu-names:
>   items:
>     - const: left
>     - const: right
> 
Agreed.
> > +
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - samsung,exynos5433-mfc
> > +    then:
> > +      properties:
> > +        clocks:
> > +          maxItems: 3
> > +        clock-names:
> > +          items:
> > +            - const: pclk
> > +            - const: aclk
> > +            - const: aclk_xiu
> > +        iommus:
> > +          maxItems: 2
> 
> the same here
> 
Agreed.
> > +
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - samsung,mfc-v7
> > +    then:
> > +      properties:
> > +        clocks:
> > +          minItems: 1
> > +          maxItems: 2
> 
> iommus:
>   maxItems: 1
> iommu-names: false
same explanation as above. Would prefer to go with
        iommus:
          minItems: 1
          maxItems: 2
        iommus-names: false
> 
> 
> Best regards,
> Krzysztof

Thanks for the review.