Re: [PATCH 02/20] dt-bindings: media: s5p-mfc: Convert s5p-mfc.txt to new DT schema

Krzysztof Kozlowski
2022-05-17T13:55:52Z

On 17/05/2022 14:55, Smitha T Murthy wrote:
> Adds DT schema for s5p-mfc in yaml format.
>

Thank you for your patch. There is something to discuss/improve.

> Cc: linux-fsd@tesla.com
> Signed-off-by: Smitha T Murthy <smitha.t@samsung.com>
> ---
> .../devicetree/bindings/media/s5p-mfc.txt | 77 +--------------
> .../devicetree/bindings/media/s5p-mfc.yaml | 98 +++++++++++++++++++
> 2 files changed, 99 insertions(+), 76 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/media/s5p-mfc.yaml
>
> diff --git a/Documentation/devicetree/bindings/media/s5p-mfc.txt b/Documentation/devicetree/bindings/media/s5p-mfc.txt
> index aa54c8159d9f..f00241ed407f 100644
> --- a/Documentation/devicetree/bindings/media/s5p-mfc.txt
> +++ b/Documentation/devicetree/bindings/media/s5p-mfc.txt
> @@ -1,76 +1 @@
> -* 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,mfc-v7" for MFC v7 present in Exynos5420 SoC
> - (d) "samsung,mfc-v8" for MFC v8 present in Exynos5800 SoC
> - (e) "samsung,exynos5433-mfc" for MFC v8 present in Exynos5433 SoC
> - (f) "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>;
> -};
> +This file has moved to s5p-mfc.yaml

Instead entirely remove the file.

> diff --git a/Documentation/devicetree/bindings/media/s5p-mfc.yaml b/Documentation/devicetree/bindings/media/s5p-mfc.yaml
> new file mode 100644
> index 000000000000..fff7c7e0d575
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/s5p-mfc.yaml
> @@ -0,0 +1,98 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/s5p-mfc.yaml#

Let's convert the name as well, so "samsung,s5p-mfc.yaml"

> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Samsung Exynos Multi Format Codec (MFC)
> +
> +maintainers:
> + - Mauro Carvalho Chehab <mchehab@kernel.org>
> + - Rob Herring <robh+dt@kernel.org>
> + - Mark Rutland <mark.rutland@arm.com>
> + - Smitha T Murthy <smitha.t@samsung.com>

Only people with access to HW, so you can put here Marek and yourself.

> +
> +properties:
> + compatible:
> + enum:
> + - samsung,mfc-v5 # Exynos4
> + - samsung,mfc-v6 # Exynos5
> + - samsung,mfc-v7 # Exynos5420
> + - samsung,mfc-v8 # Exynos5800
> + - samsung,exynos5433-mfc # Exynos5433
> + - samsung,mfc-v10 # Exynos7880

Ugh, how MFCv10 appeared here? Since 5433 we moved from versions to Soc
compatibles as recommended... eh, please follow this convention, don't
reverse it to other way.

I propose to deprecated this in next patch and instead use SoC-based
compatible.

> +
> + reg:
> + maxItems: 1
> +
> + clocks:
> + description:
> + Phandle to MFC IP clock.

Here and other places: s/Phandle//
Instead describe what is it, e.g. "MFC IP clock"

> + maxItems: 1
> +
> + clock-names:
> + description:
> + Must contain clock name (mfc) matching phandle in clocks
> + property.

Skip description, its obvious. Instead list the items.

> + maxItems: 1

No need, list the items.

> +
> + interrupts:
> + description:
> + MFC interrupt number to the CPU.

Skip description, it's obvious.

> + maxItems: 1
> +
> + memory-region:
> + description:
> + 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.
> + minItems: 1
> + maxItems: 2

This needs allOf:if:then restricting two items to specific compatible.

> +
> + iommus:
> + description:
> + Include the IOMMU domain MFC belong to.

Skip description, it's obvious.

> + maxItems: 2
> +

What happened to power domains? You also removed them from the
example... Does this pass dtbs_check?

> +required:
> + - compatible
> + - reg
> + - clocks
> + - clock-names
> + - interrupts
> + - iommus
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + /* Reserved memory specific DT entry for given board */
> + reserved-memory {

Wrong indentation. Four spaces. See example schema.

> + #address-cells = <1>;
> + #size-cells = <1>;
> + ranges;
> +
> + mfc_left: region@84000000 {
> + compatible = "shared-dma-pool";
> + no-map;
> + reg = <0x84000000 0x800000>;
> + };
> +
> + mfc_right: region@A9000000 {

lower case hex addresses, everywhere.

> + compatible = "shared-dma-pool";
> + no-map;
> + reg = <0xA9000000 0x800000>;
> + };
> + };
> +
> + mfc_0: mfc0@12880000 {

Generic node names, so mfc.

> + compatible = "samsung,mfc-v12";

Does not look like you tested the bindings. Please run `make
dt_binding_check` (see
Documentation/devicetree/bindings/writing-schema.rst for instructions).
Be sure to test your bindings before sending them.

> + reg = <0x12880000 0x10000>;
> + clock-names = "mfc";
> + interrupts = <0 137 4>;

Use interrupt defines.

> + clocks = <&clock_mfc 1>;
> + memory-region = <&mfc_left>, <&mfc_right>;
> + /* If IOMMU is present use below instead of memory-region property */
> + iommus = <&smmu_isp 0x1000 0x0>, <&smmu_isp 0x1400 0x0>;
> + };

Best regards,
Krzysztof