leds: add arduino,modulino-buttons-leds

Add an LED driver for the modulino buttons module, this has three LEDs
that are controllable independently of the buttons.

Link: https://github.com/arduino/node_modulino_firmware
Link: https://github.com/arduino-libraries/Modulino
Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>

drivers/led/CMakeLists.txt

@@ -19,6 +19,7 @@ zephyr_library_sources_ifdef(CONFIG_LP3943 lp3943.c)
 zephyr_library_sources_ifdef(CONFIG_LP50XX lp50xx.c)
 zephyr_library_sources_ifdef(CONFIG_LP5562 lp5562.c)
 zephyr_library_sources_ifdef(CONFIG_LP5569 lp5569.c)
+zephyr_library_sources_ifdef(CONFIG_MODULINO_BUTTONS_LEDS modulino_buttons_leds.c)
 zephyr_library_sources_ifdef(CONFIG_NCP5623 ncp5623.c)
 zephyr_library_sources_ifdef(CONFIG_PCA9633 pca9633.c)
 zephyr_library_sources_ifdef(CONFIG_TLC59108 tlc59108.c)

drivers/led/Kconfig

@@ -38,6 +38,7 @@ source "drivers/led/Kconfig.lp3943"
 source "drivers/led/Kconfig.lp50xx"
 source "drivers/led/Kconfig.lp5562"
 source "drivers/led/Kconfig.lp5569"
+source "drivers/led/Kconfig.modulino"
 source "drivers/led/Kconfig.ncp5623"
 source "drivers/led/Kconfig.npm1300"
 source "drivers/led/Kconfig.pca9633"

drivers/led/Kconfig.modulino

@@ -0,0 +1,10 @@
+# Copyright (c) 2025 Google, LLC
+# SPDX-License-Identifier: Apache-2.0
+
+config MODULINO_BUTTONS_LEDS
+	bool "Arduino Modulino buttons LEDs"
+	default y
+	depends on DT_HAS_ARDUINO_MODULINO_BUTTONS_LEDS_ENABLED
+	select I2C
+	help
+	  Enable driver Arduino Modulino Buttons LEDs.

drivers/led/modulino_buttons_leds.c

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT arduino_modulino_buttons_leds
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/drivers/led.h>
+#include <zephyr/kernel.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(modulino_buttons_leds, CONFIG_LED_LOG_LEVEL);
+
+#define MODULINO_BUTTONS_NUM_LEDS 3
+
+struct modulino_buttons_leds_config {
+	struct i2c_dt_spec bus;
+};
+
+struct modulino_buttons_leds_data {
+	uint8_t buf[MODULINO_BUTTONS_NUM_LEDS];
+};
+
+static int modulino_buttons_leds_set(const struct device *dev,
+				     uint32_t led, bool value)
+{
+	const struct modulino_buttons_leds_config *cfg = dev->config;
+	struct modulino_buttons_leds_data *data = dev->data;
+	int ret;
+
+	if (led >= MODULINO_BUTTONS_NUM_LEDS) {
+		return -EINVAL;
+	}
+
+	data->buf[led] = value ? 1 : 0;
+
+	ret = i2c_write_dt(&cfg->bus, data->buf, sizeof(data->buf));
+	if (ret < 0) {
+		LOG_ERR("i2c write error: %d", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int modulino_buttons_leds_on(const struct device *dev, uint32_t led)
+{
+	return modulino_buttons_leds_set(dev, led, true);
+}
+
+static int modulino_buttons_leds_off(const struct device *dev, uint32_t led)
+{
+	return modulino_buttons_leds_set(dev, led, false);
+}
+
+static int modulino_buttons_leds_set_brightness(const struct device *dev,
+						uint32_t led, uint8_t value)
+{
+	return modulino_buttons_leds_set(dev, led, value > 0);
+}
+
+static int modulino_buttons_leds_init(const struct device *dev)
+{
+	const struct modulino_buttons_leds_config *cfg = dev->config;
+	struct modulino_buttons_leds_data *data = dev->data;
+	int ret;
+
+	if (!i2c_is_ready_dt(&cfg->bus)) {
+		LOG_ERR("Bus device is not ready");
+		return -ENODEV;
+	}
+
+	/* Reset to all LEDs off */
+	ret = i2c_write_dt(&cfg->bus, data->buf, sizeof(data->buf));
+	if (ret < 0) {
+		LOG_ERR("i2c write error: %d", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static DEVICE_API(led, modulino_buttons_leds_api) = {
+	.on = modulino_buttons_leds_on,
+	.off = modulino_buttons_leds_off,
+	.set_brightness = modulino_buttons_leds_set_brightness,
+};
+
+#define MODULINO_BUTTONS_INIT(inst)							\
+	static const struct modulino_buttons_leds_config				\
+	modulino_buttons_leds_cfg_##inst = {						\
+		.bus = I2C_DT_SPEC_GET(DT_INST_PARENT(inst)),				\
+	};										\
+											\
+	static struct modulino_buttons_leds_data modulino_buttons_leds_data_##inst;	\
+											\
+	DEVICE_DT_INST_DEFINE(inst, modulino_buttons_leds_init, NULL,			\
+			      &modulino_buttons_leds_data_##inst,			\
+			      &modulino_buttons_leds_cfg_##inst,			\
+			      POST_KERNEL, CONFIG_LED_INIT_PRIORITY,			\
+			      &modulino_buttons_leds_api);
+
+
+DT_INST_FOREACH_STATUS_OKAY(MODULINO_BUTTONS_INIT)

dts/bindings/led/arduino,modulino-buttons-leds.yaml

@@ -0,0 +1,6 @@
+# Copyright (c) 2025 Google, LLC
+# SPDX-License-Identifier: Apache-2.0
+
+description: Arduino Modulino buttons LEDs
+
+compatible: "arduino,modulino-buttons-leds"