Message-ID: <512ffe3d-5ab3-4e87-afd2-46f0005a8d17@kernel.org>
Date: Tue, 14 Oct 2025 10:14:15 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Joan-Na-adi <joan.na.devcode@...il.com>,
 Liam Girdwood <lgirdwood@...il.com>
Cc: Mark Brown <broonie@...nel.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, linux-kernel@...r.kernel.org,
 devicetree@...r.kernel.org, Joan Na <joan.na@...log.com>
Subject: Re: [PATCH v3 3/3] dt-bindings: regulator: Add MAX77675 regulator
 binding

On 14/10/2025 07:31, Joan-Na-adi wrote:
> From: Joan Na <joan.na@...log.com>
> 
> Add device tree binding YAML schema for the Maxim MAX77675 PMIC regulator.
> This defines the node properties and supported regulator names for use
> in device tree sources.

A nit, subject: drop second/last, redundant "binding". The "dt-bindings"
prefix is already stating that these are bindings.
See also:
https://elixir.bootlin.com/linux/v6.17-rc3/source/Documentation/devicetree/bindings/submitting-patches.rst#L18

> 
> Fixed:
> - Missing explanation of `maxim,fps-slot` default value
> - Updated DT binding enums to use string values (e.g., "low", "high") instead of integers
> - Converted several binary properties to boolean type
> - Renamed time-based properties to use standard unit suffixes (e.g., "-sec", "-us")
> - Added default values for properties


Probably you wanted a changelog? Changelog goes to --- with details
against EACH version. Please start using b4 if canonical patch format is
tricky. b4 would help.

> 
> Signed-off-by: Joan Na <joan.na@...log.com>
> ---
>  .../bindings/regulator/maxim,max77675.yaml    | 205 ++++++++++++++++++
>  1 file changed, 205 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/regulator/maxim,max77675.yaml
> 
> diff --git a/Documentation/devicetree/bindings/regulator/maxim,max77675.yaml b/Documentation/devicetree/bindings/regulator/maxim,max77675.yaml
> new file mode 100644
> index 000000000000..6be29eced039
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/regulator/maxim,max77675.yaml
> @@ -0,0 +1,205 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/regulator/maxim,max77675.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Maxim MAX77675 PMIC Regulator
> +
> +maintainers:
> +  - Joan Na <joan.na@...log.com>
> +
> +description: |
> +  The MAX77675 is a PMIC providing multiple switching buck regulators
> +  (SBB0–SBB3), accessible via I2C. Each SBB can be configured individually
> +  in the Device Tree. Additional PMIC settings can be configured through
> +  device-specific properties.
> +  Users should use the macros from dt-bindings/regulator/maxim,max77675-regulator.h
> +
> +allOf:
> +  - $ref: regulator.yaml#
> +
> +properties:
> +  compatible:
> +    const: maxim,max77675

Please organize the patch documenting compatible (DT bindings) before
their user.
See also:
https://elixir.bootlin.com/linux/v6.14-rc6/source/Documentation/devicetree/bindings/submitting-patches.rst#L46

> +
> +  reg:
> +    maxItems: 1
> +
> +  maxim,en-mode:
> +    description: |
> +      Enable mode configuration.
> +      "push-button"  - Push button
> +      "slide-switch" - Slide switch
> +      "logic" - Logic mode

You just repeat the name in the description. Say something useful.

> +    $ref: /schemas/types.yaml#/definitions/string
> +    enum: ["push-button", "slide-switch", "logic"]
> +    default: "slide-switch"
> +
> +  maxim,latency-mode:
> +    description: |
> +      Latency mode for voltage transition:
> +      "high" - High latency (100μs)
> +      "low"  - Low latency (10μs)

So use values 100 or 10, and proper type (-us)


> +    $ref: /schemas/types.yaml#/definitions/string
> +    enum: ["high", "low"]
> +    default: "high"
> +
> +  maxim,drv-sbb-strength:
> +    description: |
> +      SIMO Buck-Boost Drive Strength Trim.
> +      Controls the drive strength of the SIMO regulator's power MOSFETs.
> +      This setting affects the switching speed, which impacts power efficiency and EMI.
> +      "max"  – Maximum drive strength (~0.6 ns transition time)
> +      "high" – High drive strength (~1.2 ns transition time)
> +      "low"  – Low drive strength (~1.8 ns transition time)
> +      "min"  – Minimum drive strength (~8 ns transition time)
> +    $ref: /schemas/types.yaml#/definitions/string
> +    enum: ["max", "high", "low", "min"]
> +    default: "max"
> +
> +  maxim,dvs-slew-rate-mv-per-us:

... like here.

> +    description: |
> +      Dynamic rising slew rate for output voltage transitions, in mV/μs.

Except you said mv/us, not us. Confusing.

> +      This setting is only used when 'maxim,fixed-slew-rate' is not present.
> +    enum: [5, 10]
> +    default: 5
> +
> +  maxim,en-debounce-time-us:
> +    description: |
> +      Debounce time for the enable pin, in microseconds
> +    enum: [100, 30000]
> +    default: 100
> +
> +  maxim,manual-reset-time-sec:
> +    description: |

Do not need '|' unless you need to preserve formatting.

> +      Manual reset time in seconds:
> +    enum: [4, 8, 12, 16]
> +    default: 4
> +
> +  maxim,en-pullup-disable:
> +    type: boolean
> +    description: |
> +      Disable internal pull-up for EN pin.
> +      When set, the internal pull-up is disabled.
> +      Defaults to enabled if this property is not specified.

This and maybe few more properties look like pinctrl bindings. Maybe
properties from pincfg are applicable?

> +    default: false
> +
> +  maxim,bias-low-power-request:
> +    type: boolean
> +    description: |
> +      Request low-power bias mode.
> +      When set, the device enters low-power bias mode.
> +      Defaults to normal bias mode if this property is not specified.
> +    default: false
> +
> +  maxim,simo-int-ldo-always-on:
> +    type: boolean
> +    description: |
> +      Set internal LDO to always supply 1.8V
> +      When set, the internal LDO always supplies 1.8V.
> +      By default, the SIMO internal channel supplies 1.8V during low-power mode
> +    default: false
> +
> +  regulators:
> +    type: object
> +    description: Regulator child nodes
> +    patternProperties:
> +      "^sbb[0-3]$":
> +        type: object
> +        $ref: regulator.yaml#
> +    properties:
> +      maxim,fps-slot:

That's not property of regulators. Totally messed indentation.


> +        description: |
> +          FPS (Flexible Power Sequencer) slot selection.
> +          The Flexible Power Sequencer allows resources to power up under hardware or software control.
> +          Additionally, each resource can power up independently or among a group of other regulators
> +          with adjustable power-up and power-down slots.
> +          This device's regulators provide an additional property to configure the FPS parameters,
> +          allowing each regulator to be assigned to an FPS slot for proper power management control.
> +          "slot0"   - Assign to FPS Slot 0
> +          "slot1"   - Assign to FPS Slot 1
> +          "slot2"   - Assign to FPS Slot 2
> +          "slot3"   - Assign to FPS Slot 3
> +          "default" - Use the default FPS slot value stored in OTP and read from the register
> +        $ref: /schemas/types.yaml#/definitions/string
> +        enum: ["slot0", "slot1", "slot2", "slot3", "default"]
> +        default: default
> +
> +      maxim,fixed-slew-rate:
> +        type: boolean
> +        description: |
> +          Use fixed slew rate of 2 mV/μs for output voltage transitions.
> +          When this property is present, the device uses a constant 2 mV/μs slew rate
> +          and ignores any dynamic slew rate configuration.
> +          When absent, the device uses the dynamic slew rate specified
> +          by 'maxim,dvs-slew-rate-mv-per-us'
> +        default: true
> +
> +    additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - regulators
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/regulator/maxim,max77675-regulator.h>
> +
> +    i2c {
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +
> +      max77675: pmic@44 {
> +        compatible = "maxim,max77675";
> +        reg = <0x44>;
> +
> +        maxim,en-mode = "slide-switch";
> +        maxim,latency-mode = "high";
> +        maxim,drv-sbb-strength = "max";
> +        maxim,dvs-slew-rate-mv-per-us = <5>;
> +        maxim,manual-reset-time-sec = <4>;
> +        maxim,en-debounce-time-us = <100>;
> +
> +        regulators {
> +          sbb0: sbb0 {
> +            regulator-name = "sbb0";
> +            regulator-min-microvolt = <500000>;
> +            regulator-max-microvolt = <5500000>;
> +            maxim,fps-slot = "default";

I don't think this was tested.


Best regards,
Krzysztof

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