On Mon, 22 Mar 2021 15:48:33 +0100, Geert Uytterhoeven wrote:

The Holtek HT16K33 LED controller is not only used for driving
dot-matrix displays, but also for driving segment displays.

Document compatible values for the Adafruit 7-segment[1] and
14-segment[2] FeatherWing expansion boards with red displays.  According
to the schematics, all other Adafruit 7-segment and 14-segment display
backpack and FeatherWing expansion boards (including bare boards and
boards fitted with displays) are compatible with these two boards.
Add a "color" property to support the different color variants.

[1] https://www.adafruit.com/product/3108
[2] https://www.adafruit.com/product/3130

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
Alternatives I considered:
  1. Document the attached display type in a child node.
     I.e. specify segment type, number of characters, and wiring.
     Especially the latter would become really complex, due to the sheer
     amount of possible wiring combinations.
     Using this method, you also loose the ability to just connect a
     display to an i2c bus, and instantiate the device from sysfs,
     without using DT:

	echo adafruit,3130 0x70 > /sys/class/i2c/i2c-adapter/.../new_device

  2. Do not use the "color" property, but document all Adafruit
     7-segment and 14-segment display backpack and FeatherWing expansion
     boards.
     This would lead to a myriad of compatible values:

      - items:
	  - enum:
	      - adafruit,878      # 0.56" 4-Digit 7-Segment Display Backpack (Red)
	      - adafruit,879      # 0.56" 4-Digit 7-Segment Display Backpack (Yellow)
	      - adafruit,880      # 0.56" 4-Digit 7-Segment Display Backpack (Green)
	      - adafruit,881      # 0.56" 4-Digit 7-Segment Display Backpack (Blue)
	      - adafruit,1002     # 0.56" 4-Digit 7-Segment Display Backpack (White)
	  - const: adafruit,877   # 0.56" 4-Digit 7-Segment Backpack
	  - const: holtek,ht16k33

      - items:
	  - enum:
	      - adafruit,1268     # 1.2" 4-Digit 7-Segment Display Backpack (Green)
	      - adafruit,1269     # 1.2" 4-Digit 7-Segment Display Backpack (Yellow)
	      - adafruit,1270     # 1.2" 4-Digit 7-Segment Display Backpack (Red)
	  - const: adafruit,1271  # 1.2" 4-Digit 7-Segment Backpack
	  - const: holtek,ht16k33

      - items:
	  - enum:
	      - adafruit,1911     # 0.54" Quad Alphanumeric Display Backpack (Red)
	      - adafruit,1912     # 0.54" Quad Alphanumeric Display Backpack (Blue)
	      - adafruit,2157     # 0.54" Quad Alphanumeric Display Backpack (White)
	      - adafruit,2158     # 0.54" Quad Alphanumeric Display Backpack (Yellow)
	      - adafruit,2159     # 0.54" Quad Alphanumeric Display Backpack (Yellow-Green)
	      - adafruit,2160     # 0.54" Quad Alphanumeric Display Backpack (Green)
	  - const: adafruit,1910  # 0.54" Quad 14-segment Alphanumeric Backpack
	  - const: holtek,ht16k33

      - items:
	  - enum:
	      - adafruit,3106     # 0.56" 4-Digit 7-Segment FeatherWing Display (Blue)
	      - adafruit,3107     # 0.56" 4-Digit 7-Segment FeatherWing Display (Green)
	      - adafruit,3108     # 0.56" 4-Digit 7-Segment FeatherWing Display (Red)
	      - adafruit,3109     # 0.56" 4-Digit 7-Segment FeatherWing Display (White)
	      - adafruit,3110     # 0.56" 4-Digit 7-Segment FeatherWing Display (Yellow)
	  - const: adafruit,3088  # 0.56" 4-Digit 7-Segment FeatherWing
	  - const: holtek,ht16k33

      - items:
	  - enum:
	      - adafruit,3127     # 0.54" Quad Alphanumeric FeatherWing Display (White)
	      - adafruit,3128     # 0.54" Quad Alphanumeric FeatherWing Display (Blue)
	      - adafruit,3129     # 0.54" Quad Alphanumeric FeatherWing Display (Green)
	      - adafruit,3130     # 0.54" Quad Alphanumeric FeatherWing Display (Red)
	      - adafruit,3131     # 0.54" Quad Alphanumeric FeatherWing Display (Yellow)
	      - adafruit,3132     # 0.54" Quad Alphanumeric FeatherWing Display (Yellow-Green)
	  - const: adafruit,3089  # 0.54" Quad 14-segment Alphanumeric FeatherWing
	  - const: holtek,ht16k33
---
 .../bindings/auxdisplay/holtek,ht16k33.yaml   | 22 ++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:
./Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml:54:16: [error] syntax error: mapping values are not allowed here (syntax)

dtschema/dtc warnings/errors:
make[1]: *** Deleting file 'Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.example.dts'
Traceback (most recent call last):
  File "/usr/local/bin/dt-extract-example", line 45, in <module>
    binding = yaml.load(open(args.yamlfile, encoding='utf-8').read())
  File "/usr/local/lib/python3.8/dist-packages/ruamel/yaml/main.py", line 343, in load
    return constructor.get_single_data()
  File "/usr/local/lib/python3.8/dist-packages/ruamel/yaml/constructor.py", line 111, in get_single_data
    node = self.composer.get_single_node()
  File "_ruamel_yaml.pyx", line 706, in _ruamel_yaml.CParser.get_single_node
  File "_ruamel_yaml.pyx", line 724, in _ruamel_yaml.CParser._compose_document
  File "_ruamel_yaml.pyx", line 775, in _ruamel_yaml.CParser._compose_node
  File "_ruamel_yaml.pyx", line 889, in _ruamel_yaml.CParser._compose_mapping_node
  File "_ruamel_yaml.pyx", line 775, in _ruamel_yaml.CParser._compose_node
  File "_ruamel_yaml.pyx", line 891, in _ruamel_yaml.CParser._compose_mapping_node
  File "_ruamel_yaml.pyx", line 904, in _ruamel_yaml.CParser._parse_next_event
ruamel.yaml.scanner.ScannerError: mapping values are not allowed in this context
  in "<unicode string>", line 54, column 16
make[1]: *** [Documentation/devicetree/bindings/Makefile:20: Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.example.dts] Error 1
make[1]: *** Waiting for unfinished jobs....
./Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml:  mapping values are not allowed in this context
  in "<unicode string>", line 54, column 16
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml: ignoring, error parsing file
warning: no schema found in file: ./Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml
make: *** [Makefile:1380: dt_binding_check] Error 2

See https://patchwork.ozlabs.org/patch/1456639

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.