Re: [PATCH v3 1/5] dt-bindings: phy: qcom,sc8280xp-qmp-pcie-phy: Add support for glymur Gen5 x8 bifurcation mode

[Krzysztof Kozlowski]

On Sun, Apr 12, 2026 at 11:25:56PM -0700, Qiang Yu wrote:
> The Glymur SoC has pcie3a and pcie3b PHYs that can operate in two modes:
> 
> 1. Independent 4-lane mode: Each PHY operates as a separate PCIe Gen5
>    4-lane interface, compatible with qcom,glymur-qmp-gen5x4-pcie-phy
> 2. Bifurcation mode (8-lane): pcie3a phy acts as leader and pcie3b phy as
>    follower to form a single 8-lane PCIe Gen5 interface
> 
> In bifurcation mode, the hardware design requires controlling additional
> resources beyond the standard pcie3a PHY configuration:
> 
> - pcie3b's aux_clk (phy_b_aux)
> - pcie3b's phy_gdsc power domain
> - pcie3b's bcr/nocsr reset
> 
> Add qcom,glymur-qmp-gen5x8-pcie-phy compatible string to document this
> 8-lane bifurcation configuration.

Do you describe PCI3A or PCI3B or something combined PCI3?

> 
> The phy_b_aux clock is used as the 6th clock instead of pipediv2,
> requiring the clock-names enum to be extended to support both
> [phy_b_aux, pipediv2] options at index 5. This follows the existing
> pattern used for [rchng, refgen] clocks at index 3.
> 
> Signed-off-by: Qiang Yu <qiang.yu@xxxxxxxxxxxxxxxx>
> ---
>  .../bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml   | 53 ++++++++++++++++++----
>  1 file changed, 45 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
> index 3a35120a77ec0ceb814a1cdcacff32fef32b4f7b..14eba5d705b1956c1bb00cc8c95171ed6488299b 100644
> --- a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
> +++ b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
> @@ -18,6 +18,7 @@ properties:
>      enum:
>        - qcom,glymur-qmp-gen4x2-pcie-phy
>        - qcom,glymur-qmp-gen5x4-pcie-phy
> +      - qcom,glymur-qmp-gen5x8-pcie-phy

That's the same device as 5x4, no? One device, one compatible and this
suggests you will have three PCI phys in the DT - two 5x4 and one 5x8?


>        - qcom,kaanapali-qmp-gen3x2-pcie-phy
>        - qcom,qcs615-qmp-gen3x1-pcie-phy
>        - qcom,qcs8300-qmp-gen4x2-pcie-phy
> @@ -68,20 +69,27 @@ properties:
>        - const: ref
>        - enum: [rchng, refgen]
>        - const: pipe
> -      - const: pipediv2
> +      - enum: [phy_b_aux, pipediv2]
>  
>    power-domains:
> -    maxItems: 1
> +    minItems: 1
> +    items:
> +      - description: PCIe PHY power domain. For PHYs supporting
> +          bifurcation mode, this is the leader PHY power domain.
> +      - description: Additional PCIe PHY power domain for PHYs supporting
> +          bifurcation mode, used by the follower PHY.
>  
>    resets:
>      minItems: 1
> -    maxItems: 2
> +    maxItems: 4
>  
>    reset-names:
>      minItems: 1
>      items:
>        - const: phy
>        - const: phy_nocsr
> +      - const: phy_b
> +      - const: phy_b_nocsr

And now I doubt that all the changes here are for duplicated node.

Maybe just the commit msg is confusing and instead of describing some
node which combines two other phys just say what device is here being
described.

Best regards,
Krzysztof