linux-kernel - Re: [PATCH 2/2] dt-bindings: regulator: Document the ltc7871 regulator

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Message-ID: <20250210-melodic-lush-bettong-9de9d0@krzk-bin>
Date: Mon, 10 Feb 2025 09:37:21 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: "Celine Joy A. Capua" <celinejoy.capua@...log.com>
Cc: Liam Girdwood <lgirdwood@...il.com>, 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
Subject: Re: [PATCH 2/2] dt-bindings: regulator: Document the ltc7871
 regulator

On Mon, Feb 10, 2025 at 10:30:53AM +0800, Celine Joy A. Capua wrote:
> The LTC7871 is a bidirectional buck or boost
> switching regulator controller that operates in
> either buck or boost mode on demand. Add
> corresponding DT bindings.

This fails tests, so limited review follows.


Please wrap commit message according to Linux coding style / submission
process (neither too early nor over the limit):
https://elixir.bootlin.com/linux/v6.4-rc1/source/Documentation/process/submitting-patches.rst#L597

Please use subject prefixes matching the subsystem. You can get them for
example with 'git log --oneline -- DIRECTORY_OR_FILE' on the directory
your patch is touching. For bindings, the preferred subjects are
explained here:
https://www.kernel.org/doc/html/latest/devicetree/bindings/submitting-patches.html#i-for-patch-submitters

> 
> Signed-off-by: Celine Joy A. Capua <celinejoy.capua@...log.com>
> ---
>  .../bindings/regulator/adi,ltc7871-regulator.yaml  | 98 ++++++++++++++++++++++
>  1 file changed, 98 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/regulator/adi,ltc7871-regulator.yaml b/Documentation/devicetree/bindings/regulator/adi,ltc7871-regulator.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..b1ae8b16e19c11b3faf2d4a41a4ae4f615ca3c1e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/regulator/adi,ltc7871-regulator.yaml
> @@ -0,0 +1,98 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright (c) 2025 Analog Devices, Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/regulator/adi,ltc7871-regulator.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices LTC7871 Buck-Boost Voltage Regulator

Blank line

> +maintainers:
> +  - Celine Joy Capua <celinejoy.capua@...log.com>
> +
> +description:
> +  The LTC7871 is a high performance bidirectional buck or boost switching
> +  regulator controller that operates in either buck or boost mode on demand.
> +  It regulates in buck mode from VHIGH-to-VLOW and boost mode from
> +  VLOW-to-VHIGH depending on a control signal, making it ideal for 48V/12V
> +  automotive dual battery systems

Blank line. Open existing bindings and see how it is done there.

> +properties:
> +  compatible:
> +    enum:
> +      - adi,ltc7871
> +      - adi,ltc7872

Are devices compatible?

> +
> +  reg:
> +    maxItems: 1
> +
> +  adi,enable-chip-ctrl-wp:
> +    description: If present, this indicates the use of regulator's
> +      internal write protection.
> +    type: boolean
> +
> +  adi,ra-external-ohms:
> +    description: External Resistor used to compute the value of
> +      programmable VLOW in buck mode.
> +    default: 10000
> +
> +  adi,rb-external-ohms:
> +    description: External Resistor used to compute the value of
> +      programmable VLOW in buck mode.
> +    default: 107000
> +
> +  adi,rc-external-ohms:
> +    description: External Resistor used to compute the value of
> +      programmable VHIGH in boost mode.
> +    default: 12700
> +
> +  adi,rd-external-ohms:
> +    description: External Resistor used to compute the value of
> +      programmable VHIGH in boost mode.
> +    default: 499000
> +
> +  adi,idac-setcur-microamp:
> +    description: Adjusts the IDAC_SETCUR to program SETCUR
> +      pin's sourcing current.
> +    minimum: -63
> +    maximum: 64
> +    default: 0
> +
> +  adi,freq-spread-percentage:
> +    description: Sets the range of modulation with respect to the
> +      switching frequency.
> +    enum: [+-12%, +-15%, +-10%, +-8%]

That's something new. Where is such property suffix defined?

> +    default: +-12%
> +
> +  adi,switching-freq-divider:
> +    description: The factor at which the switching frequency is
> +      divided to get the modulation frequency.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [512, 1024, 2048, 4096, 256, 128, 64]

Keep this ordered by increasing value.

> +    default: 512
> +
> +required:
> +  - compatible
> +  - reg

Best regards,
Krzysztof