Re: [PATCH v2 3/7] dt-bindings: usb: Add qcom,sa8255p-dwc3 for firmware-managed resources

[Faisal Hassan <faisal.hassan@oss.qualcomm.com>]

On 07-09-2026 02:38 pm, Krzysztof Kozlowski wrote:
> On Thu, Sep 03, 2026 at 09:08:23PM +0530, Faisal Hassan wrote:
>> On Qualcomm automotive SoC sa8255p, platform resources like clocks,
>> interconnects, resets, regulators and GDSC are abstracted and managed
>> collectively by firmware.
>>
>> Add a new binding file for firmware-managed USB controllers where
>> access to these resources is exposed as two power domains:
>> - Power domain: Controls power supply (GDSC) to the USB controller
>> - Bus domain: Controls clocks and interconnects for data transfer
>>
>> The binding makes power-domains and power-domain-names properties mandatory
>> for firmware-managed platforms, while excluding the clocks property since
>> clocks are managed through the power domains.
>>
>> Co-developed-by: Sriram Dash <sriram.dash@oss.qualcomm.com>
>> Signed-off-by: Sriram Dash <sriram.dash@oss.qualcomm.com>
>> Signed-off-by: Faisal Hassan <faisal.hassan@oss.qualcomm.com>
>> ---
>>   .../bindings/usb/qcom,sa8255p-dwc3.yaml       | 123 ++++++++++++++++++
>>   1 file changed, 123 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/usb/qcom,sa8255p-dwc3.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/usb/qcom,sa8255p-dwc3.yaml b/Documentation/devicetree/bindings/usb/qcom,sa8255p-dwc3.yaml
>> new file mode 100644
>> index 000000000000..c6db7bcf4981
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/usb/qcom,sa8255p-dwc3.yaml
>> @@ -0,0 +1,123 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/usb/qcom,sa8255p-dwc3.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Qualcomm SA8255P USB3 Controller with Firmware-Managed Resources
>> +
>> +maintainers:
>> +  - Wesley Cheng <wesley.cheng@oss.qualcomm.com>
>> +  - Faisal Hassan <faisal.hassan@oss.qualcomm.com>
>> +
>> +description:
>> +  USB controller on Qualcomm SA8255P automotive SoC where platform resources
>> +  such as clocks, interconnects, resets, regulators and the GDSC are
>> +  abstracted and managed collectively by firmware through SCMI (System
>> +  Control and Management Interface).
>> +
>> +  Access to these firmware-managed resources is exposed as two power
>> +  domains, one gating the power supply (GDSC) to the controller, and one
>> +  gating the clocks and interconnects used for data transfer.
>> +
>> +properties:
>> +  compatible:
>> +    const: qcom,sa8255p-dwc3
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    minItems: 1
>> +    maxItems: 6
> Why is this flexible?
>
>> +
>> +  interrupt-names:
>> +    minItems: 1
>> +    maxItems: 6
> Why is this flexible even more, allowing completely random names?
>
>> +
>> +  power-domains:
>> +    description: |
>> +      Power domains are provided by SCMI (System Control and Management
>> +      Interface). See Documentation/devicetree/bindings/firmware/arm,scmi.yaml
>> +      for details.
>> +
>> +      Exactly two power domains must be specified:
>> +        - "power": controls power supply (GDSC) to the USB controller
>> +        - "bus": controls clocks and interconnects used for data transfer
> Look at other bindings how they do it.
>
> I finished here, because you would avoid all above questions if you just
> copied recently added or reviewed on the list SA8xxx binding. You did
> not, so basically I expect more of unexpected code, which is pointless
> to review. Just open existing files...
>
> Best regards,
> Krzysztof
Hi Krzysztof,

You're right, I should have checked the existing sa8255p bindings before 
sending this. I went back and matched it against 
qcom,sa8255p-geni-uart.yaml. Will fix in v3:

- interrupts/interrupt-names: replaced the open range with a concrete 
items: list, minItems: 5/maxItems: 6.
- power-domains/power-domain-names and resets: dropped the extra 
per-property descriptions, now just bare minItems/maxItems/items like 
qcom,sa8255p-geni-uart.yaml, with the explanation kept in the top-level 
description.

Thanks,
Faisal