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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Robin van der Gracht <robin@protonic.nl>,
	Rob Herring <robh+dt@kernel.org>, Miguel Ojeda <ojeda@kernel.org>,
	Paul Burton <paulburton@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Pavel Machek <pavel@ucw.cz>, Marek Behun <marek.behun@nic.cz>
Cc: devicetree@vger.kernel.org, linux-leds@vger.kernel.org,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	Geert Uytterhoeven <geert@linux-m68k.org>
Subject: [PATCH v4 02/19] dt-bindings: auxdisplay: ht16k33: Document Adafruit segment displays
Date: Tue, 27 Jul 2021 16:04:42 +0200	[thread overview]
Message-ID: <20210727140459.3767788-3-geert@linux-m68k.org> (raw)
In-Reply-To: <20210727140459.3767788-1-geert@linux-m68k.org>

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.

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

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
v4:
  - Combine compatible values for 7/14 segment displays into an enum,

v3:
  - Drop color property,

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. 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   | 20 ++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml b/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml
index 64ffff460026040f..6baf1200c9d8488e 100644
--- a/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml
+++ b/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml
@@ -14,14 +14,21 @@ allOf:
 
 properties:
   compatible:
-    const: holtek,ht16k33
+    oneOf:
+      - items:
+          - enum:
+              - adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing Display (Red)
+              - 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
@@ -44,7 +51,14 @@ properties:
 required:
   - compatible
   - reg
-  - refresh-rate-hz
+
+if:
+  properties:
+    compatible:
+      const: holtek,ht16k33
+then:
+  required:
+    - refresh-rate-hz
 
 additionalProperties: false
 
-- 
2.25.1


  parent reply	other threads:[~2021-07-27 14:07 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-27 14:04 [PATCH v4 00/19] auxdisplay: ht16k33: Add character display support Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 01/19] uapi: Add <linux/map_to_14segment.h> Geert Uytterhoeven
2021-07-27 14:04 ` Geert Uytterhoeven [this message]
2021-08-02 20:40   ` [PATCH v4 02/19] dt-bindings: auxdisplay: ht16k33: Document Adafruit segment displays Rob Herring
2021-07-27 14:04 ` [PATCH v4 03/19] auxdisplay: img-ascii-lcd: Fix lock-up when displaying empty string Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 04/19] auxdisplay: img-ascii-lcd: Add helper variable dev Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 05/19] auxdisplay: img-ascii-lcd: Convert device attribute to sysfs_emit() Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 06/19] auxdisplay: Extract character line display core support Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 07/19] auxdisplay: linedisp: Use kmemdup_nul() helper Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 08/19] auxdisplay: linedisp: Add support for changing scroll rate Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 09/19] auxdisplay: ht16k33: Connect backlight to fbdev Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 10/19] auxdisplay: ht16k33: Use HT16K33_FB_SIZE in ht16k33_initialize() Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 11/19] auxdisplay: ht16k33: Remove unneeded error check in keypad probe() Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 12/19] auxdisplay: ht16k33: Convert to simple i2c probe function Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 13/19] auxdisplay: ht16k33: Add helper variable dev Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 14/19] auxdisplay: ht16k33: Move delayed work Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 15/19] auxdisplay: ht16k33: Extract ht16k33_brightness_set() Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 16/19] auxdisplay: ht16k33: Extract frame buffer probing Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 17/19] auxdisplay: ht16k33: Add support for segment displays Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 18/19] dt-bindings: auxdisplay: ht16k33: Document LED subnode Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 19/19] auxdisplay: ht16k33: Add LED support Geert Uytterhoeven
2021-07-27 21:05   ` Randy Dunlap
2021-07-28  7:39     ` Geert Uytterhoeven

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