Re: [PATCH 1/2] dt-bindings: mmc: sdhci-msm: Document bindings for Nord SDCC

[Krzysztof Kozlowski <krzk@kernel.org>]

On Mon, Nov 02, 2026 at 07:33:41PM +0530, Anjana Hari wrote:
> Add Device Tree binding for the Nord SDHCI variant of the Qualcomm
> sdhci-msm controller, where platform resources are managed by firmware
> through the SCMI power protocol rather than being directly accessible
> to Linux.

A nit, subject: drop second/last, redundant "bindings". The
"dt-bindings" prefix is already stating that these are bindings.
See also:
https://elixir.bootlin.com/linux/v7.1-rc7/source/Documentation/devicetree/bindings/submitting-patches.rst#L23

> 
> Unlike existing sdhci-msm variants, this binding does not require
> clock, interconnect, reset, or regulator properties. Instead, platform
> resource control is abstracted behind two logical power domains:
> 
>   - "power": controls the SDCC rail power state. The kernel requests
>     power-on and power-off transitions via the runtime PM framework;
>     these are forwarded to firmware as SCMI power-state messages.
> 
>   - "perf": exposes the supported clock frequencies as OPPs populated
>     dynamically by the SCMI perf domain driver at probe time via the
>     SCMI performance protocol. The driver selects operating points via
>     dev_pm_opp_find_freq_floor() and dev_pm_opp_set_opp().
> 
> Both domains must be listed under power-domains with their names
> declared in power-domain-names.
> 
> The compatible string "qcom,nord-sdhci" selects this variant at probe
> time and causes the driver to attach the two power domains via
> dev_pm_domain_attach_list() with PD_FLAG_DEV_LINK_ON, ensuring correct
> suspend/resume ordering between the SDCC controller and the firmware
> power domain devices.

Do not describe driver. How is it exactly relevant here for the hardware
description?

> 
> Signed-off-by: Anjana Hari <anjana.hari@oss.qualcomm.com>
> ---
>  .../devicetree/bindings/mmc/qcom,nord-sdhci.yaml   | 89 ++++++++++++++++++++++
>  1 file changed, 89 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/qcom,nord-sdhci.yaml b/Documentation/devicetree/bindings/mmc/qcom,nord-sdhci.yaml
> new file mode 100644
> index 000000000000..c512628617b0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mmc/qcom,nord-sdhci.yaml
> @@ -0,0 +1,89 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mmc/qcom,nord-sdhci.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm Nord SDHCI Controller
> +
> +maintainers:
> +  - Anjana Hari <anjana.hari@oss.qualcomm.com>
> +
> +description:
> +  SDHCI (SD Host Controller Interface) present on Qualcomm Nord SoC.
> +  Clock and power resources are managed by firmware through an SCMI
> +  server, so no clock entries are required in the device tree node.
> +
> +properties:
> +  compatible:
> +    const: qcom,nord-sdhci
> +
> +  reg:
> +    maxItems: 1
> +
> +  reg-names:
> +    items:
> +      - const: hc

Where is CQHCI?

> +
> +  interrupts:
> +    maxItems: 2
> +
> +  interrupt-names:
> +    items:
> +      - const: hc_irq
> +      - const: pwr_irq
> +
> +  iommus:
> +    maxItems: 1
> +    description: phandle to the apps SMMU node with SID mask.

Drop description

> +
> +  dma-coherent: true
> +
> +  power-domains:
> +    maxItems: 2
> +
> +  power-domain-names:
> +    items:
> +      - const: power
> +      - const: perf

Best regards,
Krzysztof