Re: [PATCH 03/17] dt-bindings: display/msm: Document Nord MDSS

[Dmitry Baryshkov]

On Thu, Sep 17, 2026 at 11:12:38AM +0530, Nabige Aala wrote:
> 
> On 9/17/2026 7:06 AM, Shawn Guo wrote:
> > On Fri, Sep 11, 2026 at 09:06:34PM +0530, Nabige Aala wrote:
> > > From: Mahadevan P <mahadevan.p@xxxxxxxxxxxxxxxx>
> > > 
> > > Add the binding for the display subsystem (MDSS) found on the Qualcomm
> > > Nord SoC. Nord is MDSS 12.1, DP-only (no DSI), with two independent DP
> > > controllers.
> > > 
> > > Signed-off-by: Mahadevan P <mahadevan.p@xxxxxxxxxxxxxxxx>
> > > Signed-off-by: Nabige Aala <nabige.aala@xxxxxxxxxxxxxxxx>
> > > ---
> > >   .../bindings/display/msm/qcom,nord-mdss.yaml       | 98 ++++++++++++++++++++++
> > >   1 file changed, 98 insertions(+)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/display/msm/qcom,nord-mdss.yaml b/Documentation/devicetree/bindings/display/msm/qcom,nord-mdss.yaml
> > > new file mode 100644
> > > index 000000000000..0b0cacdca9db
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/display/msm/qcom,nord-mdss.yaml
> > > @@ -0,0 +1,98 @@
> > > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/display/msm/qcom,nord-mdss.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Qualcomm Nord display subsystem (MDSS)
> > > +
> > > +maintainers:
> > > +  - Mahadevan P <mahadevan.p@xxxxxxxxxxxxxxxx>
> > > +
> > > +description:
> > > +  Nord display subsystem consists of MDSS (display controller), DPU 1499A
> > > +  (display processing unit), and display interface controllers (DP only, no DSI).
> > > +  This is MDSS 12.1, DP-only, with 2 independent DP controllers.
> > > +
> > > +$ref: /schemas/display/msm/mdss-common.yaml#
> > > +
> > > +properties:
> > > +  compatible:
> > > +    const: qcom,nord-mdss
> > > +
> > > +  clocks:
> > > +    items:
> > > +      - description: Display AHB
> > > +      - description: Display hf AXI
> > > +      - description: Display core
> > > +
> > > +  clock-names:
> > > +    items:
> > > +      - const: iface
> > > +      - const: bus
> > > +      - const: core
> > > +
> > > +  iommus:
> > > +    maxItems: 1
> > The DTS in downstream repository doesn't seem to agree. There is two
> > items for iommus.
> 
> I checked the Nord IPCAT. the resulted SID is same for both the SID (i.e. 
> 0x03e0) in downstream repository.
> 
> I think we should update the downstream DT and use a single SID entry.
> 
> > > +
> > > +  interconnects:
> > > +    items:
> > > +      - description: Interconnect path from mdp0 port to the data bus
> > > +      - description: Interconnect path from CPU to the reg bus
> > > +
> > > +  interconnect-names:
> > > +    items:
> > > +      - const: mdp0-mem
> > > +      - const: cpu-cfg
> > > +
> > > +patternProperties:
> > > +  "^display-controller@[0-9a-f]+$":
> > > +    type: object
> > > +    additionalProperties: true
> > > +    properties:
> > > +      compatible:
> > > +        const: qcom,nord-dpu
> > > +
> > > +  "^displayport-controller@[0-9a-f]+$":
> > > +    type: object
> > > +    additionalProperties: true
> > > +    properties:
> > > +      compatible:
> > > +        const: qcom,nord-dp
> > > +
> > > +  "^phy@[0-9a-f]+$":
> > > +    type: object
> > > +    additionalProperties: true
> > > +    properties:
> > > +      compatible:
> > > +        const: qcom,nord-dp-phy
> > > +
> > > +required:
> > > +  - compatible
> > > +
> > > +unevaluatedProperties: false
> > > +
> > > +examples:
> > > +  - |
> > > +    #include <dt-bindings/clock/qcom,dispcc-nord.h>
> > Please run dt_binding_check against mainline kernel where the header is
> > actually qcom,nord-dispcc.h.
> 
> Ack, I will update according to mainline kernel.

Just drop the header from the bindings and use ephemeral clocks and
resets.


-- 
With best wishes
Dmitry