Re: [PATCH v4 03/20] dt-bindings: mfd: Add starfive,jh7110-hdmi-subsystem

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] dt-bindings: mfd: bus fault during PHY probe due to artificial node split
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commit 4723344ba643109500316c0b52d890ec9a27e43e
Author: Michal Wilczynski <m.wilczynski@samsung.com>

dt-bindings: mfd: Add starfive,jh7110-hdmi-subsystem
    
Add the dt-binding for the StarFive JH7110 HDMI subsystem.
    
The JH7110 HDMI IP is a monolithic block containing both the digital
controller and analog PHY in a single register space. This binding
defines the parent device, which holds the shared register map and
populates its two children: the PHY and the controller. This is
necessary to resolve a circular clock dependency between the HDMI block
and the VOUT clock generator.

> diff --git a/Documentation/devicetree/bindings/mfd/starfive,jh7110-hdmi-subsystem.yaml b/Documentation/devicetree/bindings/mfd/starfive,jh7110-hdmi-subsystem.yaml
> new file mode 100644
> index 0000000000000..18034d8273b86
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/starfive,jh7110-hdmi-subsystem.yaml
> @@ -0,0 +1,95 @@

[ ... ]

> +properties:
> +  compatible:
> +    const: starfive,jh7110-hdmi-subsystem
> +
> +  reg:
> +    maxItems: 1
> +
> +  phy:
> +    $ref: /schemas/phy/starfive,jh7110-inno-hdmi-phy.yaml#
> +
> +  controller:
> +    $ref: /schemas/display/bridge/starfive,jh7110-inno-hdmi-controller.yaml#

[Severity: High]
Does this artificial split of a monolithic block into child nodes create a
probe order issue?

Because the controller depends on the phy (via clocks = <&hdmi_phy> in the
example below), fw_devlink guarantees the phy driver probes first. During
its probe, the phy driver calls clk_set_rate(inno->phyclk, 297000000),
which accesses the shared register space via regmap.

However, since the HDMI system clock (JH7110_VOUTCLK_HDMI_TX_SYS) is
assigned exclusively to the controller child, it is not enabled during the
phy probe.

Will this unclocked access wedge the bus and cause a synchronous external
abort when the phy accesses the shared register window?

> +
> +required:
> +  - compatible
> +  - reg
> +  - phy
> +  - controller
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/starfive,jh7110-crg.h>
> +    #include <dt-bindings/reset/starfive,jh7110-crg.h>
> +
> +    soc {
> +        #address-cells = <1>;
> +        #size-cells = <1>;
> +
> +        hdmi@29590000 {
> +            compatible = "starfive,jh7110-hdmi-subsystem";
> +            reg = <0x29590000 0x4000>;
> +
> +            controller {
> +                compatible = "starfive,jh7110-inno-hdmi-controller";
> +                clocks = <&voutcrg JH7110_VOUTCLK_HDMI_TX_SYS>,
> +                         <&voutcrg JH7110_VOUTCLK_HDMI_TX_MCLK>,
> +                         <&voutcrg JH7110_VOUTCLK_HDMI_TX_BCLK>,
> +                         <&hdmi_phy>;

[ ... ]

> +            hdmi_phy: phy {
> +                compatible = "starfive,jh7110-inno-hdmi-phy";
> +                #clock-cells = <0>;
> +                clocks = <&xin24m>;
> +                #phy-cells = <0>;
> +            };
> +        };
> +    };
> +...

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Sashiko AI review · https://sashiko.dev/#/patchset/20260915-jh7110-clean-send-v4-0-f0e4fd6f2cc8@samsung.com?part=3