linux-kernel - Re: [PATCH v15 1/3] dt-bindings: leds: add TI/National Semiconductor LP5812 LED Driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20251009201620.GA3267176-robh@kernel.org>
Date: Thu, 9 Oct 2025 15:16:20 -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 v15 1/3] dt-bindings: leds: add TI/National Semiconductor
 LP5812 LED Driver

On Sun, Oct 05, 2025 at 10:33:35PM +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   | 290 ++++++++++++++++++
>  MAINTAINERS                                   |   6 +
>  2 files changed, 296 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..d759ba7a86fc
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/ti,lp5812.yaml
> @@ -0,0 +1,290 @@
> +# 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,operation-mode:
> +    description: |
> +      Selects the LED operation 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).

I would make this the default and call the property 'ti,scan-mode'.

> +        - TCM-drive mode ("tcmscan:<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 ("mixscan:<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
> +    enum:
> +      - direct_mode
> +      - tcmscan:1:0
> +      - tcmscan:1:1
> +      - tcmscan:1:2
> +      - tcmscan:1:3
> +      - tcmscan:2:0:1
> +      - tcmscan:2:0:2
> +      - tcmscan:2:0:3
> +      - tcmscan:2:1:2
> +      - tcmscan:2:1:3
> +      - tcmscan:2:2:3
> +      - tcmscan:3:0:1:2
> +      - tcmscan:3:0:1:3
> +      - tcmscan:3:0:2:3
> +      - tcmscan:4:0:1:2:3
> +      - mixscan:1:0:1
> +      - mixscan:1:0:2
> +      - mixscan:1:0:3
> +      - mixscan:1:1:0
> +      - mixscan:1:1:2
> +      - mixscan:1:1:3
> +      - mixscan:1:2:0
> +      - mixscan:1:2:1
> +      - mixscan:1:2:3
> +      - mixscan:1:3:0
> +      - mixscan:1:3:1
> +      - mixscan:1:3:2
> +      - mixscan:2:0:1:2
> +      - mixscan:2:0:1:3
> +      - mixscan:2:0:2:3
> +      - mixscan:2:1:0:2
> +      - mixscan:2:1:0:3
> +      - mixscan:2:1:2:3
> +      - mixscan:2:2:0:1
> +      - mixscan:2:2:0:3
> +      - mixscan:2:2:1:3
> +      - mixscan:2:3:0:1
> +      - mixscan:2:3:0:2
> +      - mixscan:2:3:1:2
> +      - mixscan:3:0:1:2:3
> +      - mixscan:3:1:0:2:3
> +      - mixscan:3:2:0:1:3
> +      - mixscan:3:3:0:1:2

I'm not sure its worth listing out every combination. I'd just do this 
even if illegal combinations are allowed:

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

Rob