Re: [PATCH v1 1/6] dt-bindings: leds: Document TI LM3533 LED controller

[Jonathan Cameron]

On Sun, 17 May 2026 10:43:01 +0300
Svyatoslav Ryhel <clamor95@xxxxxxxxx> wrote:

> Document the LM3533 - a complete power source for backlight, keypad and
> indicator LEDs in smartphone handsets. The high-voltage inductive boost
> converter provides the power for two series LED strings display backlight
> and keypad functions.
> 
> Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
Hi Svyatoslav,

I focused on the ALS part.. A few comments.

> +# see ti,lm3533.yaml for an example
> diff --git a/Documentation/devicetree/bindings/leds/ti,lm3533.yaml b/Documentation/devicetree/bindings/leds/ti,lm3533.yaml
> new file mode 100644
> index 000000000000..2e200f172400
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/ti,lm3533.yaml
> @@ -0,0 +1,190 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/ti,lm3533.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: TI LM3533 Complete Lighting Power Solution
> +
> +description: >
> +  The LM3533 is a complete power source for backlight, keypad, and indicator LEDs
> +  in smartphone handsets. The high-voltage inductive boost converter provides the
> +  power for two high voltage series LED strings for display backlight and four low
> +  voltage control banks for individual LEDs. Additionally, LM3533 features an ALS
> +  sensor support.
Mention it is an interface for an external ALS.

> +  light-sensor:
> +    type: object
> +    additionalProperties: false
> +
> +    properties:
> +      compatible:
> +        const: ti,lm3533-als
> +
> +      interrupts:
> +        maxItems: 1
> +
> +      ti,resistor-ohm:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Internal configuration resister value when ALS is in Analog Sensor
> +          mode and PWM mode is disabled.

Good to note why this is a firmware thing rather than a userspace controlled
thing. I looked it up, it's because expectation is the input is a current from
the external analog ALS and these are used to convert it to a voltage with target
range.

> +        minimum: 1575
> +        maximum: 200000
> +
> +      ti,pwm-mode:
> +        type: boolean
> +        description:
> +          Switch for mode in which ALS is running. If this property is set
> +          then ALS is running in PWM mode, internal resistor value is set to
> +          high-impedance (0) and ti,resistor-ohm property is ignored.
I'd mention the ALS is an external device - so this is saying what interface thing
thing connected is using.

> +
> +    required:
> +      - compatible
> +
> +    anyOf:
> +      - required:
> +          - ti,resistor-ohm
> +      - required:
> +          - ti,pwm-mode
> +
> +patternProperties:
> +  "^backlight@[01]$":
> +    $ref: /schemas/leds/backlight/ti,lm3533-backlight.yaml#
> +
> +  "^led@[2-5]$":
> +    $ref: /schemas/leds/ti,lm3533-leds.yaml#
> +
> +required:
> +  - compatible
> +  - reg
> +  - light-sensor
> +  - backlight@0
> +  - backlight@1

Similar for the led nodes.

> +  - led@2
> +  - led@3
> +  - led@4
> +  - led@5

Curious - why are all the led nodes required?  What if some aren't wired to anything?

> +
> +additionalProperties: false