diff mbox series

[v2,02/18] dt-bindings: auxdisplay: ht16k33: Document Adafruit segment displays

Message ID 20210625125902.1162428-3-geert@linux-m68k.org
State New
Headers show
Series None | expand

Commit Message

Geert Uytterhoeven June 25, 2021, 12:58 p.m. UTC
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>
---
v2:
  - Fix type of color to uint32,
  - "refresh-rate-hz" is still required for dot-matrix displays.

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   | 31 +++++++++++++++++--
 1 file changed, 28 insertions(+), 3 deletions(-)

Comments

Rob Herring (Arm) July 14, 2021, 8:36 p.m. UTC | #1
On Fri, Jun 25, 2021 at 02:58:46PM +0200, 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>

> ---

> v2:

>   - Fix type of color to uint32,

>   - "refresh-rate-hz" is still required for dot-matrix displays.

> 

> 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   | 31 +++++++++++++++++--

>  1 file changed, 28 insertions(+), 3 deletions(-)

> 

> diff --git a/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml b/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml

> index 64ffff460026040f..616aca817874bdc8 100644

> --- a/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml

> +++ b/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml

> @@ -14,14 +14,23 @@ allOf:

>  

>  properties:

>    compatible:

> -    const: holtek,ht16k33

> +    oneOf:

> +      - items:

> +          - const: adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing Display (Red)

> +          - const: holtek,ht16k33

> +

> +      - items:

> +          - const: adafruit,3130  # 0.54" Quad Alphanumeric FeatherWing Display (Red)

> +          - const: holtek,ht16k33


These 2 entries can be combined. Or make the comment a 'description'.

> +

> +      - const: holtek,ht16k33     # Generic 16*8 LED controller with dot-matrix display

>  

>    reg:

>      maxItems: 1

>  

>    refresh-rate-hz:

>      maxItems: 1

> -    description: Display update interval in Hertz

> +    description: Display update interval in Hertz for dot-matrix displays

>  

>    interrupts:

>      maxItems: 1

> @@ -41,10 +50,26 @@ properties:

>      default: 16

>      description: Initial brightness level

>  

> +  color:

> +    description:

> +      Color of the display.  Use one of the LED_COLOR_ID_* prefixed definitions

> +      from the header include/dt-bindings/leds/common.h.  The default is red.

> +    $ref: /schemas/types.yaml#/definitions/uint32

> +    minimum: 0

> +    maximum: 9

> +    default: 1

> +

>  required:

>    - compatible

>    - reg

> -  - refresh-rate-hz

> +

> +if:

> +  properties:

> +    compatible:

> +      const: holtek,ht16k33


Isn't this always true?

> +then:

> +  required:

> +    - refresh-rate-hz

>  

>  additionalProperties: false

>  

> -- 

> 2.25.1

> 

>
Rob Herring (Arm) July 15, 2021, 2:32 p.m. UTC | #2
On Thu, Jul 15, 2021 at 1:12 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>

> Hi Rob,

>

> Note that you commented on v2, while I posted v3 yesterday.

>

> On Wed, Jul 14, 2021 at 10:36 PM Rob Herring <robh@kernel.org> wrote:

> > On Fri, Jun 25, 2021 at 02:58:46PM +0200, 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>

>

> > > --- a/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml

> > > +++ b/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml

> > > @@ -14,14 +14,23 @@ allOf:

> > >

> > >  properties:

> > >    compatible:

> > > -    const: holtek,ht16k33

> > > +    oneOf:

> > > +      - items:

> > > +          - const: adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing Display (Red)

> > > +          - const: holtek,ht16k33

> > > +

> > > +      - items:

> > > +          - const: adafruit,3130  # 0.54" Quad Alphanumeric FeatherWing Display (Red)

> > > +          - const: holtek,ht16k33

> >

> > These 2 entries can be combined.

>

> Right.  This split dates back from when I considered adding all

> possible compatible values.  It can indeed be simplified to:

>

>           - enum:

>               - adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing

> Display (Red)

>               - adafruit,3130  # 0.54" Quad Alphanumeric FeatherWing

> Display (Red)

>           - const: holtek,ht16k33

>

> > Or make the comment a 'description'.

>

> What do you mean?


Adding this:

description: '0.54" Quad Alphanumeric FeatherWing Display (Red)'


> > > +

> > > +      - const: holtek,ht16k33     # Generic 16*8 LED controller with dot-matrix display

>

> > >  required:

> > >    - compatible

> > >    - reg

> > > -  - refresh-rate-hz

> > > +

> > > +if:

> > > +  properties:

> > > +    compatible:

> > > +      const: holtek,ht16k33

> >

> > Isn't this always true?

>

> It is false if there is more than one compatible value.


Ah, yes.

Rob
Geert Uytterhoeven July 15, 2021, 3:06 p.m. UTC | #3
Hi Rob,

On Thu, Jul 15, 2021 at 4:32 PM Rob Herring <robh@kernel.org> wrote:
> On Thu, Jul 15, 2021 at 1:12 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> > On Wed, Jul 14, 2021 at 10:36 PM Rob Herring <robh@kernel.org> wrote:

> > > On Fri, Jun 25, 2021 at 02:58:46PM +0200, 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>

> >

> > > > --- a/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml

> > > > +++ b/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml

> > > > @@ -14,14 +14,23 @@ allOf:

> > > >

> > > >  properties:

> > > >    compatible:

> > > > -    const: holtek,ht16k33

> > > > +    oneOf:

> > > > +      - items:

> > > > +          - const: adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing Display (Red)

> > > > +          - const: holtek,ht16k33

> > > > +

> > > > +      - items:

> > > > +          - const: adafruit,3130  # 0.54" Quad Alphanumeric FeatherWing Display (Red)

> > > > +          - const: holtek,ht16k33

> > >

> > > These 2 entries can be combined.

> >

> > Right.  This split dates back from when I considered adding all

> > possible compatible values.  It can indeed be simplified to:

> >

> >           - enum:

> >               - adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing

> > Display (Red)

> >               - adafruit,3130  # 0.54" Quad Alphanumeric FeatherWing

> > Display (Red)

> >           - const: holtek,ht16k33

> >

> > > Or make the comment a 'description'.

> >

> > What do you mean?

>

> Adding this:

>

> description: '0.54" Quad Alphanumeric FeatherWing Display (Red)'


Sorry, I still don't get it.
Note that there are two different adafruit,NNNN compatible values.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml b/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml
index 64ffff460026040f..616aca817874bdc8 100644
--- a/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml
+++ b/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml
@@ -14,14 +14,23 @@  allOf:
 
 properties:
   compatible:
-    const: holtek,ht16k33
+    oneOf:
+      - items:
+          - const: adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing Display (Red)
+          - const: holtek,ht16k33
+
+      - items:
+          - const: adafruit,3130  # 0.54" Quad Alphanumeric FeatherWing Display (Red)
+          - const: holtek,ht16k33
+
+      - const: holtek,ht16k33     # Generic 16*8 LED controller with dot-matrix display
 
   reg:
     maxItems: 1
 
   refresh-rate-hz:
     maxItems: 1
-    description: Display update interval in Hertz
+    description: Display update interval in Hertz for dot-matrix displays
 
   interrupts:
     maxItems: 1
@@ -41,10 +50,26 @@  properties:
     default: 16
     description: Initial brightness level
 
+  color:
+    description:
+      Color of the display.  Use one of the LED_COLOR_ID_* prefixed definitions
+      from the header include/dt-bindings/leds/common.h.  The default is red.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 0
+    maximum: 9
+    default: 1
+
 required:
   - compatible
   - reg
-  - refresh-rate-hz
+
+if:
+  properties:
+    compatible:
+      const: holtek,ht16k33
+then:
+  required:
+    - refresh-rate-hz
 
 additionalProperties: false