linux-kernel - Re: [PATCH v16 1/3] dt-bindings: leds: add TI/National Semiconductor LP5812 LED Driver

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Message-ID: <20251015165648.GA4046261-robh@kernel.org>
Date: Wed, 15 Oct 2025 11:56:48 -0500
From: Rob Herring <robh@...nel.org>
To: Nam Tran <trannamatk@...il.com>
Cc: lee@...nel.org, pavel@...nel.org, gregkh@...uxfoundation.org,
	rdunlap@...radead.org, christophe.jaillet@...adoo.fr,
	krzk+dt@...nel.org, conor+dt@...nel.org, corbet@....net,
	linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v16 1/3] dt-bindings: leds: add TI/National Semiconductor
 LP5812 LED Driver

On Tue, Oct 14, 2025 at 12:35:49AM +0700, Nam Tran wrote:
> The LP5812 is a 4x3 RGB LED driver with an autonomous animation
> engine and time-cross-multiplexing (TCM) support for up to 12 LEDs
> or 4 RGB LEDs. It supports both analog (256 levels) and PWM (8-bit)
> dimming, including exponential PWM for smooth brightness control.
> 
> Signed-off-by: Nam Tran <trannamatk@...il.com>
> ---
>  .../devicetree/bindings/leds/ti,lp5812.yaml   | 249 ++++++++++++++++++
>  MAINTAINERS                                   |   6 +
>  2 files changed, 255 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/ti,lp5812.yaml
> 
> diff --git a/Documentation/devicetree/bindings/leds/ti,lp5812.yaml b/Documentation/devicetree/bindings/leds/ti,lp5812.yaml
> new file mode 100644
> index 000000000000..5208ddb3bdac
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/ti,lp5812.yaml
> @@ -0,0 +1,249 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/ti,lp5812.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: TI LP5812 4x3 Matrix RGB LED Driver with Autonomous Control
> +
> +maintainers:
> +  - Nam Tran <trannamatk@...il.com>
> +
> +description: |
> +  The LP5812 is a 4x3 matrix RGB LED driver with I2C interface
> +  and autonomous animation engine control.
> +  For more product information please see the link below:
> +  https://www.ti.com/product/LP5812#tech-docs
> +
> +properties:
> +  compatible:
> +    const: ti,lp5812
> +
> +  reg:
> +    maxItems: 1
> +
> +  ti,scan-mode:
> +    description: |
> +      Selects the LED scan mode of the LP5812. The device supports
> +      three modes:
> +        - Direct-drive mode ("direct_mode") drives up to 4 LEDs directly
> +        by internal current sinks (LED0-LED3).
> +        - TCM-drive mode ("tcm:<n>:<order...>") drives up to 12 LEDs
> +        (4 RGB) using 1-4 scan multiplexing. The <n> specifies the number
> +        of scans (1-4), and <order...> defines the scan order of the outputs.
> +        - Mix-drive mode ("mix:<n>:<direct>:<order...>") combines
> +        direct-drive and TCM-drive outputs. The <n> specifies the number
> +        of scans, <direct> selects the direct-drive outputs, and <order...>
> +        defines the scan order.
> +    $ref: /schemas/types.yaml#/definitions/string
> +    oneOf:
> +      - const: direct_mode

My suggestion was to drop direct_mode and make no 'ti,scan-mode' 
property present mean 'use direct mode'. As direct mode is essentially 
what every other LED driver IC supports, supporting it as the 
default with no property makes sense.

> +      - pattern: '^(tcm|mix):[1-4](:[0-3]){1,4}$'