Re: [RFC V2 3/6] dt-bindings: media: nxp,imx8mq-vpu: Update the bindings for G2 support

[Lucas Stach <l.stach@pengutronix.de>]

Hi Rob,

Am Dienstag, dem 07.12.2021 um 09:14 -0600 schrieb Rob Herring:
> On Mon, Dec 06, 2021 at 07:54:42PM -0600, Adam Ford wrote:
> > From: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> > 
> > Introducing the G2 hevc video decoder requires modifications of the bindings to allow
> > one node per VPU.
> 
> Why? It looks like the G2 part was already described. If you are 
> changing this because you want 2 drivers for G1 and G2, then NAK. DT 
> nodes and drivers don't have to be 1:1. This change is breaking 
> compatibility.

We can keep the compatibility by just keeping the code in the VPU
driver to handle the G1 block as-is. The VPU block on the imx8mq is
really three peripherals: the control block working together with the
power domain controller to provide clocks and resets and the G1 and G2
VPU cores.

> 
> > 
> > VPUs share one hardware control block which is provided as a phandle on
> > a syscon.
> 
> That's not really ideal. Is this really a separate block?
> 
This part of the commit message is not accurate anymore. The control
block is in fact so separate from the VPU that we even added a new
driver to handle those control blocks: the imx8m blk-ctrl driver. The
VPU driver doesn't need handle this control block anymore, it's now
handled via the power-domain abstraction.

Regards,
Lucas

> > Each node has now one reg and one interrupt.
> > Add a compatible for G2 hardware block: nxp,imx8mq-vpu-g2.
> > 
> > To be compatible with older DT the driver is still capable to use the 'ctrl'
> > reg-name even if it is deprecated now.
> > 
> > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> > Signed-off-by: Adam Ford <aford173@gmail.com>
> > 
> > diff --git a/Documentation/devicetree/bindings/media/nxp,imx8mq-vpu.yaml b/Documentation/devicetree/bindings/media/nxp,imx8mq-vpu.yaml
> > index 762be3f96ce9..eaeba4ce262a 100644
> > --- a/Documentation/devicetree/bindings/media/nxp,imx8mq-vpu.yaml
> > +++ b/Documentation/devicetree/bindings/media/nxp,imx8mq-vpu.yaml
> > @@ -15,37 +15,36 @@ description:
> >  
> >  properties:
> >    compatible:
> > -    const: nxp,imx8mq-vpu
> > +    oneOf:
> > +      - const: nxp,imx8mq-vpu-g1
> > +      - const: nxp,imx8mq-vpu-g2
> >  
> >    reg:
> > -    maxItems: 3
> > -
> > -  reg-names:
> > -    items:
> > -      - const: g1
> > -      - const: g2
> > -      - const: ctrl
> > +    maxItems: 1
> >  
> >    interrupts:
> > -    maxItems: 2
> > +    maxItems: 1
> >  
> >    interrupt-names:
> > -    items:
> > +    oneOf:
> >        - const: g1
> >        - const: g2
> >  
> >    clocks:
> > -    maxItems: 3
> > +    maxItems: 1
> >  
> >    clock-names:
> > -    items:
> > +    oneOf:
> >        - const: g1
> >        - const: g2
> > -      - const: bus
> >  
> >    power-domains:
> >      maxItems: 1
> >  
> > +  nxp,imx8m-vpu-ctrl:
> > +    description: Specifies a phandle to syscon VPU hardware control block
> > +    $ref: "/schemas/types.yaml#/definitions/phandle"
> 
> This is optional?
> 
> > +
> >  required:
> >    - compatible
> >    - reg
> > @@ -60,20 +59,27 @@ additionalProperties: false
> >  examples:
> >    - |
> >          #include <dt-bindings/clock/imx8mq-clock.h>
> > +        #include <dt-bindings/power/imx8mq-power.h>
> >          #include <dt-bindings/interrupt-controller/arm-gic.h>
> >  
> > -        vpu: video-codec@38300000 {
> > +        vpu_g1: video-codec@38300000 {
> >                  compatible = "nxp,imx8mq-vpu";
> > -                reg = <0x38300000 0x10000>,
> > -                      <0x38310000 0x10000>,
> > -                      <0x38320000 0x10000>;
> > -                reg-names = "g1", "g2", "ctrl";
> > -                interrupts = <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
> > -                             <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>;
> > -                interrupt-names = "g1", "g2";
> > -                clocks = <&clk IMX8MQ_CLK_VPU_G1_ROOT>,
> > -                         <&clk IMX8MQ_CLK_VPU_G2_ROOT>,
> > -                         <&clk IMX8MQ_CLK_VPU_DEC_ROOT>;
> > -                clock-names = "g1", "g2", "bus";
> > -                power-domains = <&pgc_vpu>;
> > +                reg = <0x38300000 0x10000>;
> > +                reg-names "g1";
> > +                interrupts = <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>;
> > +                interrupt-names = "g1";
> > +                clocks = <&clk IMX8MQ_CLK_VPU_G2_ROOT>;
> > +                clock-names = "g1";
> > +                power-domains = <&vpu_blk_ctrl IMX8MQ_VPUBLK_PD_G1>;
> > +        };
> > +
> > +        vpu_g2: video-codec@38310000 {
> > +                compatible = "nxp,imx8mq-vpu-g2";
> > +                reg = <0x38300000 0x10000>;
> > +                reg-names "g2";
> > +                interrupts = <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>;
> > +                interrupt-names = "g2";
> > +                clocks = <&clk IMX8MQ_CLK_VPU_G2_ROOT>;
> > +                clock-names = "g2";
> > +                power-domains = <&vpu_blk_ctrl IMX8MQ_VPUBLK_PD_G2>;
> >          };
> > -- 
> > 2.32.0
> > 
> >