[PATCH 0/2] input: add GPIO-based charlieplex keypad

[PATCH 0/2] input: add GPIO-based charlieplex keypad

[Hugo Villeneuve]

From: Hugo Villeneuve <hvilleneuve@dimonoff.com>

Hello,
this patch series add a new GPIO charlieplex keypad driver.

I have tested the driver on a custom board with a Solidrun RZ/G2LC SOM
with three charlieplex keyboards, all connected thru a a PCA9416 I2C GPIO
expander.

Thank you.

Hugo Villeneuve (2):
  dt-bindings: input: add GPIO charlieplex keypad
  Input: charlieplex_keypad: add GPIO charlieplex keypad

 .../input/gpio-charlieplex-keypad.yaml        |  88 +++++++
 MAINTAINERS                                   |   7 +
 drivers/input/keyboard/Kconfig                |  14 ++
 drivers/input/keyboard/Makefile               |   1 +
 drivers/input/keyboard/charlieplex_keypad.c   | 223 ++++++++++++++++++
 5 files changed, 333 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.yaml
 create mode 100644 drivers/input/keyboard/charlieplex_keypad.c


base-commit: ed8a4ef29da3821ee3155d3b1925fa67fc92aae2
-- 
2.47.3

[PATCH 1/2] dt-bindings: input: add GPIO charlieplex keypad

[Hugo Villeneuve]

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)
+        >;
+    };
-- 
2.47.3

[PATCH 2/2] Input: charlieplex_keypad: add GPIO charlieplex keypad

[Hugo Villeneuve]

From: Hugo Villeneuve <hvilleneuve@dimonoff.com>

Add support for GPIO-based charlieplex keypad, allowing to control
N^2-N keys using N GPIO lines.

Reuse matrix keypad keymap to simplify, even if there is no concept
of rows and columns in this type of keyboard.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
---
 MAINTAINERS                                 |   7 +
 drivers/input/keyboard/Kconfig              |  14 ++
 drivers/input/keyboard/Makefile             |   1 +
 drivers/input/keyboard/charlieplex_keypad.c | 223 ++++++++++++++++++++
 4 files changed, 245 insertions(+)
 create mode 100644 drivers/input/keyboard/charlieplex_keypad.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 9ed6d11a77466..0b2d71f32b400 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5765,6 +5765,13 @@ S:	Maintained
 F:	Documentation/hwmon/powerz.rst
 F:	drivers/hwmon/powerz.c
 
+CHARLIEPLEX KEYPAD DRIVER
+M:	Hugo Villeneuve <hvilleneuve@dimonoff.com>
+S:	Supported
+W:	http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/electronic-circuits/matrix-keypad-scan-decode
+F:	Documentation/devicetree/bindings/input/gpio-charlieplex-keypad.yaml
+F:	drivers/input/keyboard/charlieplex_keypad.c
+
 CHECKPATCH
 M:	Andy Whitcroft <apw@canonical.com>
 M:	Joe Perches <joe@perches.com>
diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 2ff4fef322c24..ae54b4b7e2d8a 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -289,6 +289,20 @@ config KEYBOARD_MATRIX
 	  To compile this driver as a module, choose M here: the
 	  module will be called matrix_keypad.
 
+config KEYBOARD_CHARLIEPLEX
+	tristate "GPIO driven chearlieplex keypad support"
+	depends on GPIOLIB || COMPILE_TEST
+	select INPUT_MATRIXKMAP
+	help
+	  Enable support for GPIO driven charlieplex keypad. A charlieplex
+	  keypad allows to use fewer GPIO lines to interface to key switches.
+	  For example, an N lines charlieplex keypad can be used to interface
+	  to N^2-N different key switches. However, this type of keypad
+	  cannot detect more than one key press at a time.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called charlieplex_keypad.
+
 config KEYBOARD_HIL_OLD
 	tristate "HP HIL keyboard support (simple driver)"
 	depends on GSC || HP300
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 2d906e14f3e27..40b5cf5d374d2 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_KEYBOARD_LOCOMO)		+= locomokbd.o
 obj-$(CONFIG_KEYBOARD_LPC32XX)		+= lpc32xx-keys.o
 obj-$(CONFIG_KEYBOARD_MAPLE)		+= maple_keyb.o
 obj-$(CONFIG_KEYBOARD_MATRIX)		+= matrix_keypad.o
+obj-$(CONFIG_KEYBOARD_CHARLIEPLEX)	+= charlieplex_keypad.o
 obj-$(CONFIG_KEYBOARD_MAX7359)		+= max7359_keypad.o
 obj-$(CONFIG_KEYBOARD_MAX7360)		+= max7360-keypad.o
 obj-$(CONFIG_KEYBOARD_MPR121)		+= mpr121_touchkey.o
diff --git a/drivers/input/keyboard/charlieplex_keypad.c b/drivers/input/keyboard/charlieplex_keypad.c
new file mode 100644
index 0000000000000..f9d6f5ecfa8dc
--- /dev/null
+++ b/drivers/input/keyboard/charlieplex_keypad.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  GPIO driven charlieplex keypad driver
+ *
+ *  Copyright (c) 2025 Hugo Villeneuve <hvilleneuve@dimonoff.com>
+ *
+ *  Based on matrix_keyboard.c
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/input.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/types.h>
+
+struct charlieplex_keypad {
+	struct input_dev *input_dev;
+	struct gpio_descs *line_gpios;
+	unsigned int nlines;
+	unsigned int line_scan_delay_us;
+	unsigned int debounce_threshold;
+	unsigned int debounce_count;
+	int debounce_code;
+	int current_code;
+};
+
+static void charlieplex_keypad_report_key(struct input_dev *input)
+{
+	struct charlieplex_keypad *keypad = input_get_drvdata(input);
+	const unsigned short *keycodes = input->keycode;
+
+	if (keypad->current_code > 0) {
+		input_event(input, EV_MSC, MSC_SCAN, keypad->current_code);
+		input_report_key(input, keycodes[keypad->current_code], 0);
+	}
+
+	if (keypad->debounce_code) {
+		input_event(input, EV_MSC, MSC_SCAN, keypad->debounce_code);
+		input_report_key(input, keycodes[keypad->debounce_code], 1);
+	}
+
+	input_sync(input);
+	keypad->current_code = keypad->debounce_code;
+}
+
+static void charlieplex_keypad_check_switch_change(struct input_dev *input,
+						   int code)
+{
+	struct charlieplex_keypad *keypad = input_get_drvdata(input);
+
+	if (code != keypad->debounce_code) {
+		keypad->debounce_count = 0;
+		keypad->debounce_code = code;
+	} else if (keypad->debounce_count < keypad->debounce_threshold) {
+		keypad->debounce_count++;
+
+		if (keypad->debounce_count >= keypad->debounce_threshold &&
+		    keypad->debounce_code != keypad->current_code)
+			charlieplex_keypad_report_key(input);
+	}
+}
+
+static void charlieplex_keypad_poll(struct input_dev *input)
+{
+	struct charlieplex_keypad *keypad = input_get_drvdata(input);
+	int oline;
+	int code;
+
+	for (code = 0, oline = 0; oline < keypad->nlines; oline++) {
+		DECLARE_BITMAP(values, MATRIX_MAX_ROWS);
+		int iline;
+		int rc;
+
+		/* Activate only one line as output at a time. */
+		gpiod_direction_output(keypad->line_gpios->desc[oline], 1);
+
+		if (keypad->line_scan_delay_us)
+			fsleep(keypad->line_scan_delay_us);
+
+		/* Read input on all other lines. */
+		rc = gpiod_get_array_value_cansleep(keypad->line_gpios->ndescs,
+						    keypad->line_gpios->desc,
+						    keypad->line_gpios->info, values);
+		if (rc)
+			return;
+
+		for (iline = 0; iline < keypad->nlines; iline++) {
+			if (iline == oline)
+				continue; /* Do not read active output line. */
+
+			/* Check if GPIO is asserted. */
+			if (test_bit(iline, values)) {
+				code = MATRIX_SCAN_CODE(oline, iline,
+							get_count_order(keypad->nlines));
+				/*
+				 * Exit loop immediately since we cannot detect
+				 * more than one key press at a time.
+				 */
+				break;
+			}
+		}
+
+		gpiod_direction_input(keypad->line_gpios->desc[oline]);
+
+		if (code)
+			break;
+	}
+
+	charlieplex_keypad_check_switch_change(input, code);
+}
+
+static int charlieplex_keypad_init_gpio(struct platform_device *pdev,
+					struct charlieplex_keypad *keypad)
+{
+	bool active_low;
+	int nkeys;
+	int i;
+
+	keypad->line_gpios = devm_gpiod_get_array(&pdev->dev, "line", GPIOD_IN);
+	if (IS_ERR(keypad->line_gpios))
+		return PTR_ERR(keypad->line_gpios);
+
+	keypad->nlines = keypad->line_gpios->ndescs;
+
+	if (keypad->nlines > MATRIX_MAX_ROWS)
+		return -EINVAL;
+
+	nkeys = (keypad->nlines * keypad->nlines) - keypad->nlines;
+
+	active_low = device_property_read_bool(&pdev->dev, "gpio-activelow");
+
+	for (i = 0; i < keypad->nlines; i++) {
+		gpiod_set_consumer_name(keypad->line_gpios->desc[i], "charlieplex_kbd_line");
+
+		if (active_low ^ gpiod_is_active_low(keypad->line_gpios->desc[i]))
+			gpiod_toggle_active_low(keypad->line_gpios->desc[i]);
+	}
+
+	return 0;
+}
+
+static int charlieplex_keypad_probe(struct platform_device *pdev)
+{
+	struct charlieplex_keypad *keypad;
+	unsigned int debounce_interval_ms;
+	unsigned int poll_interval_ms;
+	struct input_dev *input_dev;
+	int err;
+
+	keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
+	if (!keypad)
+		return -ENOMEM;
+
+	input_dev = devm_input_allocate_device(&pdev->dev);
+	if (!input_dev)
+		return -ENOMEM;
+
+	keypad->input_dev = input_dev;
+
+	device_property_read_u32(&pdev->dev, "poll-interval", &poll_interval_ms);
+	device_property_read_u32(&pdev->dev, "debounce-delay-ms", &debounce_interval_ms);
+	device_property_read_u32(&pdev->dev, "line-scan-delay-us", &keypad->line_scan_delay_us);
+
+	keypad->current_code = -1;
+	keypad->debounce_code = -1;
+	keypad->debounce_threshold = DIV_ROUND_UP(debounce_interval_ms, poll_interval_ms);
+
+	err = charlieplex_keypad_init_gpio(pdev, keypad);
+	if (err)
+		return err;
+
+	input_dev->name		= pdev->name;
+	input_dev->id.bustype	= BUS_HOST;
+
+	err = matrix_keypad_build_keymap(NULL, NULL, keypad->nlines,
+					 keypad->nlines, NULL, input_dev);
+	if (err)
+		dev_err_probe(&pdev->dev, -ENOMEM, "failed to build keymap\n");
+
+	if (!device_property_read_bool(&pdev->dev, "linux,no-autorepeat"))
+		__set_bit(EV_REP, input_dev->evbit);
+
+	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
+
+	err = input_setup_polling(input_dev, charlieplex_keypad_poll);
+	if (err)
+		dev_err_probe(&pdev->dev, err, "unable to set up polling\n");
+
+	input_set_poll_interval(input_dev, poll_interval_ms);
+
+	input_set_drvdata(input_dev, keypad);
+
+	err = input_register_device(keypad->input_dev);
+	if (err)
+		return err;
+
+	platform_set_drvdata(pdev, keypad);
+
+	return 0;
+}
+
+static const struct of_device_id charlieplex_keypad_dt_match[] = {
+	{ .compatible = "gpio-charlieplex-keypad" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, charlieplex_keypad_dt_match);
+
+static struct platform_driver charlieplex_keypad_driver = {
+	.probe		= charlieplex_keypad_probe,
+	.driver		= {
+		.name	= "charlieplex-keypad",
+		.of_match_table = of_match_ptr(charlieplex_keypad_dt_match),
+	},
+};
+module_platform_driver(charlieplex_keypad_driver);
+
+MODULE_AUTHOR("Hugo Villeneuve <hvilleneuve@dimonoff.com>");
+MODULE_DESCRIPTION("GPIO driven charlieplex keypad driver");
+MODULE_LICENSE("GPL");
-- 
2.47.3

Re: [PATCH 1/2] dt-bindings: input: add GPIO charlieplex keypad

[Rob Herring (Arm)]

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.

Re: [PATCH 1/2] dt-bindings: input: add GPIO charlieplex keypad

[Hugo Villeneuve]

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

Re: [PATCH 2/2] Input: charlieplex_keypad: add GPIO charlieplex keypad

[kernel test robot]

Hi Hugo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on ed8a4ef29da3821ee3155d3b1925fa67fc92aae2]

url:    https://github.com/intel-lab-lkp/linux/commits/Hugo-Villeneuve/dt-bindings-input-add-GPIO-charlieplex-keypad/20260204-001338
base:   ed8a4ef29da3821ee3155d3b1925fa67fc92aae2
patch link:    https://lore.kernel.org/r/20260203155023.536103-3-hugo%40hugovil.com
patch subject: [PATCH 2/2] Input: charlieplex_keypad: add GPIO charlieplex keypad
config: parisc-randconfig-r072-20260204 (https://download.01.org/0day-ci/archive/20260204/202602040703.1Bu56Htu-lkp@intel.com/config)
compiler: hppa-linux-gcc (GCC) 8.5.0
smatch version: v0.5.0-8994-gd50c5a4c
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260204/202602040703.1Bu56Htu-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202602040703.1Bu56Htu-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/input/keyboard/charlieplex_keypad.c: In function 'charlieplex_keypad_init_gpio':
>> drivers/input/keyboard/charlieplex_keypad.c:120:6: warning: variable 'nkeys' set but not used [-Wunused-but-set-variable]
     int nkeys;
         ^~~~~


vim +/nkeys +120 drivers/input/keyboard/charlieplex_keypad.c

   115	
   116	static int charlieplex_keypad_init_gpio(struct platform_device *pdev,
   117						struct charlieplex_keypad *keypad)
   118	{
   119		bool active_low;
 > 120		int nkeys;
   121		int i;
   122	
   123		keypad->line_gpios = devm_gpiod_get_array(&pdev->dev, "line", GPIOD_IN);
   124		if (IS_ERR(keypad->line_gpios))
   125			return PTR_ERR(keypad->line_gpios);
   126	
   127		keypad->nlines = keypad->line_gpios->ndescs;
   128	
   129		if (keypad->nlines > MATRIX_MAX_ROWS)
   130			return -EINVAL;
   131	
   132		nkeys = (keypad->nlines * keypad->nlines) - keypad->nlines;
   133	
   134		active_low = device_property_read_bool(&pdev->dev, "gpio-activelow");
   135	
   136		for (i = 0; i < keypad->nlines; i++) {
   137			gpiod_set_consumer_name(keypad->line_gpios->desc[i], "charlieplex_kbd_line");
   138	
   139			if (active_low ^ gpiod_is_active_low(keypad->line_gpios->desc[i]))
   140				gpiod_toggle_active_low(keypad->line_gpios->desc[i]);
   141		}
   142	
   143		return 0;
   144	}
   145	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 1/2] dt-bindings: input: add GPIO charlieplex keypad

[Dmitry Torokhov]

Hi 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

Re: [PATCH 1/2] dt-bindings: input: add GPIO charlieplex keypad

[Hugo Villeneuve]

On Thu, 5 Feb 2026 01:24:05 -0800
Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote:

Hi Dmitry,

> Hi 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.

Ok, I based my binding/driver on gpio-matrix-keypad, which had
linux,no-autorepeat.
I will change that in V2 (along with driver source code changes).

> 
> > +
> > +  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.

You are right, again "contamination" from gpio-matrix-keypad :)

I will also change that in V2 (along with driver source code changes).

Thank you,
Hugo.