Re: [PATCH 2/3] media: dt-bindings: rockchip: Document RK3588 Video Decoder 2 bindings

[Heiko Stuebner <heiko@sntech.de>]

Am Samstag, 15. Juni 2024, 21:49:21 CEST schrieb Detlev Casanova:
> On Saturday, June 15, 2024 4:11:00 A.M. EDT Jonas Karlman wrote:
> > Hi Detlev,
> > 
> > On 2024-06-15 03:56, Detlev Casanova wrote:
> > > Document the Rockchip RK3588 Video Decoder 2 bindings.
> > 
> > Why the need for a new schema file and not just extending existing
> > rockchip,vdec.yaml with a new compatible and the new clock?
> 
> Yes, that can work as well indeed. I wasn't sure if different drivers could 
> share a schema file.
> 
> > > Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> > > ---
> > > 
> > >  .../bindings/media/rockchip,vdec2.yaml        | 80 +++++++++++++++++++
> > >  1 file changed, 80 insertions(+)
> > >  create mode 100644
> > >  Documentation/devicetree/bindings/media/rockchip,vdec2.yaml> 
> > > diff --git a/Documentation/devicetree/bindings/media/rockchip,vdec2.yaml
> > > b/Documentation/devicetree/bindings/media/rockchip,vdec2.yaml new file
> > > mode 100644
> > > index 000000000000..e54891b46986
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/media/rockchip,vdec2.yaml
> > > @@ -0,0 +1,80 @@
> > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/media/rockchip,vdec2.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Rockchip Video Decoder 2 (VDec2)
> > > +
> > > +maintainers:
> > > +  - Heiko Stuebner <heiko@sntech.de>
> > > +
> > > +description: |-
> > > +  The Rockchip rk3588 has a stateless Video Decoder that can decodes
> > > H.264, +  HEVC, VP9 and AVS2 streams.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    const: rockchip,rk3588-vdec2
> > 
> > I fail to see the need to call this vdec2 instead of established vdec.
> > 
> > Suggest this is changed to rockchip,rk3588-vdec.
> 
> Wouldn't that be misleading if rockchip,rk3399-vdec and rockchip,rk3588-vdec 
> use different drivers ?

Devicetrees and their binding don't care about how operating system
implement things in drivers. 

While they come with the Linux-kernel most of the time, they are pretty
much independent from implementation details.


> > > +
> > > +  reg:
> > > +    maxItems: 1
> > > +
> > > +  interrupts:
> > > +    maxItems: 1
> > > +
> > > +  clocks:
> > > +    items:
> > > +      - description: The Video decoder AXI interface clock
> > > +      - description: The Video decoder AHB interface clock
> > > +      - description: The Video decoder core clock
> > > +      - description: The Video decoder CABAC clock
> > > +      - description: The Video decoder HEVC CABAC clock
> > > +
> > > +  clock-names:
> > > +    items:
> > > +      - const: axi
> > > +      - const: ahb
> > > +      - const: core
> > > +      - const: cabac
> > > +      - const: hevc_cabac
> > > +
> > > +  assigned-clocks: true
> > > +
> > > +  assigned-clock-rates: true
> > > +
> > > +  power-domains:
> > > +    maxItems: 1
> > > +
> > > +required:
> > > +  - compatible
> > > +  - reg
> > > +  - interrupts
> > > +  - clocks
> > > +  - clock-names
> > > +  - power-domains
> > > +
> > > +additionalProperties: false
> > > +
> > > +examples:
> > > +  - |
> > > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > > +    #include <dt-bindings/clock/rockchip,rk3588-cru.h>
> > > +    #include <dt-bindings/power/rk3588-power.h>
> > > +
> > > +    vdec2: video-codec@fdc38100 {
> > > +        compatible = "rockchip,rk3588-vdec2";
> > > +        reg = <0x0 0xfdc38100 0x0 0x500>;
> > > +        interrupts = <GIC_SPI 95 IRQ_TYPE_LEVEL_HIGH 0>;
> > > +        clocks = <&cru ACLK_RKVDEC0>, <&cru HCLK_RKVDEC0>, <&cru
> > > CLK_RKVDEC0_CORE>, +                 <&cru CLK_RKVDEC0_CA>, <&cru
> > > CLK_RKVDEC0_HEVC_CA>; +        clock-names = "axi", "ahc", "core",
> > > +                      "cabac", "hevc_cabac";
> > > +        assigned-clocks = <&cru ACLK_RKVDEC0>, <&cru CLK_RKVDEC0_CORE>,
> > > +                          <&cru CLK_RKVDEC0_CA>, <&cru
> > > CLK_RKVDEC0_HEVC_CA>; +        assigned-clock-rates = <800000000>,
> > > <600000000>,
> > > +                               <600000000>, <1000000000>;
> > > +        power-domains = <&power RK3588_PD_RKVDEC0>;
> > 
> > iommus and resets seem to be missing?
> 
> Indeed, even if their are not used yet, I'd make sens to already have them 
> here to stabilize the device tree, right ?

correct. DT only ever describes the hardware. And while it is possible
to extend bindings later, having the obvious things in it from the start
makes a lot of sense.