Re: [PATCH v6 3/7] dt-bindings: auxdisplay: add Titan Micro Electronics TM16xx

Rob Herring
2025-12-04T15:42:29Z

On Fri, Nov 21, 2025 at 09:59:03AM -0500, Jean-François Lessard wrote:
> Add documentation for TM16xx-compatible 7-segment LED display controllers
> with keyscan.
>
> Signed-off-by: Jean-François Lessard <jefflessard3@gmail.com>
> ---
>
> Notes:
> The 'segments' property is intentionally not vendor-prefixed as it
> defines a generic hardware description concept applicable to any
> 7-segment display controller. The property describes the fundamental
> grid/segment coordinate mapping that is controller-agnostic and could
> be reused by other LED matrix display bindings. Similar to how 'gpios'
> describes GPIO connections generically, 'segments' describes segment
> connections in a standardized way using uint32-matrix format.
>
> The property uses explicit coordinate pairs to handle real-world
> hardware variations. Some board manufacturers use standard layouts
> (same grid, different segments per digit) while others use transposed
> layouts (same segment, different grids per digit). The coordinate-pair
> approach accommodates both patterns without requiring separate arrays
> or boolean flags, as confirmed acceptable by DT maintainers.
>
> Retained 'properties:' wrapper for spi-3wire in conditional block.
> Rob Herring suggested removing it, but dt_binding_check requires
> explicit 'properties:' context when referencing peripheral
> properties within allOf conditional sections to satisfy
> unevaluatedProperties validation. This follows the pattern in
> spi-controller.yaml itself.
>
> .../bindings/auxdisplay/titanmec,tm16xx.yaml | 465 ++++++++++++++++++
> MAINTAINERS | 5 +
> 2 files changed, 470 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/auxdisplay/titanmec,tm16xx.yaml
>
> diff --git a/Documentation/devicetree/bindings/auxdisplay/titanmec,tm16xx.yaml b/Documentation/devicetree/bindings/auxdisplay/titanmec,tm16xx.yaml
> new file mode 100644
> index 000000000000..a852d8b8882c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/auxdisplay/titanmec,tm16xx.yaml
> @@ -0,0 +1,465 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/auxdisplay/titanmec,tm16xx.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Auxiliary displays based on TM16xx and compatible LED controllers
> +
> +maintainers:
> + - Jean-François Lessard <jefflessard3@gmail.com>
> +
> +description: |
> + LED matrix controllers used in auxiliary display devices that drive individual
> + LED icons and 7-segment digit groups through a grid/segment addressing scheme.
> + Controllers manage a matrix of LEDs organized as grids (columns/banks in
> + vendor datasheets) and segments (rows/bit positions in vendor datasheets).
> + Maximum brightness and grid/segment indices are controller-specific.
> + Controller-specific maximum are validated in the driver.
> +
> + The controller is agnostic of the display layout. Board-specific LED wiring is
> + described through child nodes that specify grid/segment coordinates for
> + individual icons and segment mapping for 7-segment digits.
> +
> + The bindings use separate 'leds' and 'digits' containers to accommodate
> + different addressing schemes:
> + - LEDs use 2-cell addressing (grid, segment) for matrix coordinates
> + - Digits use 1-cell addressing with explicit segment mapping
> +
> + The controller node exposes a logical LED-like control for the aggregate
> + display brightness. Child nodes describe individual icons and 7-seg digits.
> + The top-level control supports only label and brightness-related properties
> + and does not support other common LED properties such as color or function.
> + Child LED nodes use the standard LED binding.
> +
> + Optional keypad scanning is supported when both 'linux,keymap' and
> + 'poll-interval' properties are specified.
> +
> +properties:
> + compatible:
> + oneOf:
> + - items:
> + - enum:
> + - fdhisi,fd628
> + - princeton,pt6964
> + - wxicore,aip1628
> + - const: titanmec,tm1628
> + - items:
> + - enum:
> + - wxicore,aip1618
> + - const: titanmec,tm1618
> + - items:
> + - enum:
> + - fdhisi,fd650
> + - wxicore,aip650
> + - const: titanmec,tm1650
> + - enum:
> + - fdhisi,fd620
> + - fdhisi,fd655
> + - fdhisi,fd6551
> + - titanmec,tm1618
> + - titanmec,tm1620
> + - titanmec,tm1628
> + - titanmec,tm1638
> + - titanmec,tm1650
> + - winrise,hbs658
> +
> + reg:
> + maxItems: 1
> +
> + label:
> + description:
> + The label for the top-level LED. If omitted, the label is taken from the
> + node name (excluding the unit address). It has to uniquely identify a
> + device, i.e. no other LED class device can be assigned the same label.
> +
> + max-brightness:
> + minimum: 0 # 0=off
> + maximum: 8 # Maximum across all TM16xx controllers
> + description:
> + Normally the maximum brightness is determined by the hardware and this
> + property is not required. This property is used to put a software limit
> + on the brightness apart from what the driver says, as it could happen
> + that a LED can be made so bright that it gets damaged or causes damage
> + due to restrictions in a specific system, such as mounting conditions.
> +
> + default-brightness:
> + minimum: 0 # 0=off
> + maximum: 8 # Maximum across all TM16xx controllers
> + description:
> + Brightness to be set if LED's default state is on. Used only during
> + initialization. If the option is not set then max brightness is used.
> +
> + digits:
> + type: object
> + description: Container for 7-segment digit group definitions
> + additionalProperties: false
> +
> + properties:
> + "#address-cells":
> + const: 1
> + "#size-cells":
> + const: 0
> +
> + patternProperties:
> + "^digit@[0-9a-f]+$":
> + type: object
> + unevaluatedProperties: false
> +
> + properties:
> + reg:
> + description:
> + Digit position identifier numbered sequentially left-to-right,
> + with reg=0 representing the leftmost digit position as displayed
> + to the user.
> + maxItems: 1
> +
> + segments:
> + $ref: /schemas/types.yaml#/definitions/uint32-matrix
> + description: |
> + Array of grid/segment coordinate pairs for each 7-segment position.
> + Each entry is <grid segment> mapping to standard 7-segment positions
> + in order: a, b, c, d, e, f, g
> +
> + Standard 7-segment layout:
> + aaa
> + f b
> + f b
> + ggg
> + e c
> + e c
> + ddd
> + items:
> + items:
> + - description: Grid index
> + - description: Segment index
> + minItems: 7
> + maxItems: 7
> +
> + required:
> + - reg
> + - segments
> +
> + leds:
> + type: object
> + description: Container for individual LED icon definitions
> + additionalProperties: false
> +
> + properties:
> + "#address-cells":
> + const: 2
> + "#size-cells":
> + const: 0
> +
> + patternProperties:
> + "^led@[0-9a-f]+,[0-9a-f]+$":
> + type: object
> + description:
> + Individual LED icon addressed by <grid>,<segment> matrix coordinates.
> + $ref: /schemas/leds/common.yaml#
> + unevaluatedProperties: false
> +
> + properties:
> + reg:
> + description:
> + Grid and segment indices as <grid segment> of this individual LED icon
> +
> + required:
> + - reg
> +
> +dependencies:
> + poll-interval:
> + - linux,keymap
> + linux,keymap:
> + - poll-interval
> + autorepeat:
> + - linux,keymap
> + - poll-interval
> +
> +required:
> + - compatible
> + - reg
> +
> +allOf:
> + - $ref: /schemas/leds/common.yaml#
> + properties:
> + color: false
> + function: false
> + function-enumerator: false
> + - $ref: /schemas/input/input.yaml#
> + - $ref: /schemas/input/matrix-keymap.yaml#
> + # SPI controllers require 3-wire (combined MISO/MOSI line)
> + - if:
> + properties:
> + compatible:
> + contains:
> + enum:
> + - fdhisi,fd620
> + - fdhisi,fd628
> + - princeton,pt6964
> + - titanmec,tm1618
> + - titanmec,tm1620
> + - titanmec,tm1628
> + - titanmec,tm1638
> + - wxicore,aip1618
> + - wxicore,aip1628
> + then:
> + $ref: /schemas/spi/spi-peripheral-props.yaml#
> + properties:
> + spi-3wire: true

You can drop properties here.

Otherwise,

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

> + required:
> + - spi-3wire