From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Add DT bindings for GPIO charlieplex keypad.
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
---
.../input/gpio-charlieplex-keypad.yaml | 88 +++++++++++++++++++
1 file changed, 88 insertions(+)
create mode 100644 Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.yaml
diff --git a/Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.yaml b/Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.yaml
new file mode 100644
index 0000000000000..b382c8caa096d
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.yaml
@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+
+$id: http://devicetree.org/schemas/input/gpio-charlieplex-keypad.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: GPIO charlieplex keypad
+
+maintainers:
+ - Hugo Villeneuve <hvilleneuve@dimonoff.com>
+
+description:
+ The charlieplex keypad supports N^2)-N different key combinations (where N is
+ the number of lines). Key presses and releases are detected by configuring
+ only one line as output at a time, and reading other line states. This process
+ is repeated for each line.
+ This mechanism doesn't allow to detect simultaneous key presses.
+
+allOf:
+ - $ref: input.yaml#
+ - $ref: /schemas/input/matrix-keymap.yaml#
+
+properties:
+ compatible:
+ const: gpio-charlieplex-keypad
+
+ line-scan-delay-us:
+ description:
+ Delay, measured in microseconds, that is needed
+ before we can scan keypad after activating one line.
+ default: 0
+
+ line-gpios:
+ description:
+ List of GPIOs used as lines. The gpio specifier for this property
+ depends on the gpio controller to which these lines are connected.
+
+ linux,keymap: true
+
+ linux,no-autorepeat:
+ type: boolean
+ description: Do not enable autorepeat feature.
+
+ gpio-activelow:
+ type: boolean
+ description:
+ Force GPIO polarity to active low.
+ In the absence of this property GPIOs are treated as active high.
+
+ debounce-delay-ms:
+ description: Debounce interval in milliseconds.
+ default: 5
+
+ poll-interval: true
+
+ wakeup-source: true
+
+required:
+ - compatible
+ - line-gpios
+ - linux,keymap
+ - poll-interval
+
+additionalProperties: false
+
+examples:
+ - |
+ charlieplex-keypad {
+ compatible = "gpio-charlieplex-keypad";
+ debounce-delay-ms = <20>;
+ poll-interval = <5>;
+ line-scan-delay-us = <2>;
+
+ line-gpios = <&gpio2 25 0
+ &gpio2 26 0
+ &gpio2 27 0>;
+
+ /* MATRIX_KEY(output, input, key-code) */
+ linux,keymap = <
+ MATRIX_KEY(0, 1, KEY_F1)
+ MATRIX_KEY(0, 2, KEY_F2)
+ MATRIX_KEY(1, 0, KEY_F3)
+ MATRIX_KEY(1, 2, KEY_F4)
+ MATRIX_KEY(2, 0, KEY_F5)
+ MATRIX_KEY(2, 1, KEY_F6)
+ >;
+ };
--
2.47.3Hi Hugo, On Tue, Feb 03, 2026 at 10:49:47AM -0500, Hugo Villeneuve wrote: > From: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > Add DT bindings for GPIO charlieplex keypad. > ... > + linux,no-autorepeat: > + type: boolean > + description: Do not enable autorepeat feature. Let's use standard "autorepeat" property to enable autorepeat when needed. > + > + gpio-activelow: > + type: boolean > + description: > + Force GPIO polarity to active low. > + In the absence of this property GPIOs are treated as active high. No, the polarity should be encoded in individual GPIOs, not via a separate property. Thanks. -- Dmitry
On Tue, 03 Feb 2026 10:49:47 -0500, Hugo Villeneuve wrote: > From: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > Add DT bindings for GPIO charlieplex keypad. > > Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> > --- > .../input/gpio-charlieplex-keypad.yaml | 88 +++++++++++++++++++ > 1 file changed, 88 insertions(+) > create mode 100644 Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.yaml > My bot found errors running 'make dt_binding_check' on your patch: yamllint warnings/errors: dtschema/dtc warnings/errors: Lexical error: Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.example.dts:30.17-27 Unexpected 'MATRIX_KEY' Error: Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.example.dts:30.29-30 syntax error FATAL ERROR: Unable to parse input tree make[2]: *** [scripts/Makefile.dtbs:132: Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.example.dtb] Error 1 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [/builds/robherring/dt-review-ci/linux/Makefile:1525: dt_binding_check] Error 2 make: *** [Makefile:248: __sub-make] Error 2 doc reference errors (make refcheckdocs): See https://patchwork.kernel.org/project/devicetree/patch/20260203155023.536103-2-hugo@hugovil.com The base for the series is generally the latest rc1. A different dependency should be noted in *this* patch. 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 after running the above command yourself. Note that DT_SCHEMA_FILES can be set to your schema file to speed up checking your schema. However, it must be unset to test all examples with your schema.
On Tue, 03 Feb 2026 12:17:49 -0600 "Rob Herring (Arm)" <robh@kernel.org> wrote: > > On Tue, 03 Feb 2026 10:49:47 -0500, Hugo Villeneuve wrote: > > From: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > > > Add DT bindings for GPIO charlieplex keypad. > > > > Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > --- > > .../input/gpio-charlieplex-keypad.yaml | 88 +++++++++++++++++++ > > 1 file changed, 88 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.yaml > > > > My bot found errors running 'make dt_binding_check' on your patch: > > yamllint warnings/errors: > > dtschema/dtc warnings/errors: > Lexical error: Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.example.dts:30.17-27 Unexpected 'MATRIX_KEY' > Error: Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.example.dts:30.29-30 syntax error > FATAL ERROR: Unable to parse input tree > make[2]: *** [scripts/Makefile.dtbs:132: Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.example.dtb] Error 1 > make[2]: *** Waiting for unfinished jobs.... > make[1]: *** [/builds/robherring/dt-review-ci/linux/Makefile:1525: dt_binding_check] Error 2 > make: *** [Makefile:248: __sub-make] Error 2 Hi, I will add: #include <dt-bindings/input/input.h> to the example section to fix this in V2. Thank you, Hugo. > doc reference errors (make refcheckdocs): > > See https://patchwork.kernel.org/project/devicetree/patch/20260203155023.536103-2-hugo@hugovil.com > > The base for the series is generally the latest rc1. A different dependency > should be noted in *this* patch. > > 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 after running the above command yourself. Note > that DT_SCHEMA_FILES can be set to your schema file to speed up checking > your schema. However, it must be unset to test all examples with your schema. > > -- Hugo Villeneuve
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