samples: drivers: led: add ktd202x driver sample

Adds sample application for Kinetic KTD202X 3/4 channel LED driver

Signed-off-by: Michael Estes <michael.estes@byteserv.io>

samples/drivers/led/ktd202x/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(led_pca9633)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

samples/drivers/led/ktd202x/README.rst

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+.. zephyr:code-sample:: ktd202x
+   :name: KTD202X LED
+   :relevant-api: led_interface
+
+   Control 3 LEDs connected to a KTD2026 driver chip.
+
+Overview
+********
+
+This sample controls 3 LEDs connected to a KTD2026 driver, using the
+following pattern:
+
+ 1. turn on LEDs
+ 2. turn off LEDs
+ 3. set the brightness to 50%
+ 4. turn off LEDs
+ 5. blink the LEDs
+ 6. turn off LEDs
+
+Building and Running
+********************
+
+Build the application for the :zephyr:board:`nucleo_g431rb` board, and connect
+a KTD2026 LED driver on the bus I2C Arduino.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/drivers/led/ktd2026
+   :board: nucleo_g431rb_board
+   :goals: build
+   :compact:
+
+For flashing the application, refer to the Flashing section of the
+:zephyr:board:`nucleo_g431rb` board documentation.
+
+References
+**********
+
+- KTD202X: https://www.kinet-ic.com/uploads/web/KTD2026/KTD2026-7-04h.pdf

samples/drivers/led/ktd202x/app.overlay

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+/* SPDX-License-Identifier: Apache-2.0 */
+
+&arduino_i2c {
+	status = "okay";
+	clock-frequency = <I2C_BITRATE_STANDARD>;
+
+	ktd202x@30 {
+		compatible = "kinetic,ktd202x";
+		reg = <0x30>;
+	};
+};

samples/drivers/led/ktd202x/prj.conf

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+CONFIG_LOG=y
+
+CONFIG_LED=y

samples/drivers/led/ktd202x/sample.yaml

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+sample:
+  description: Demonstration of the KTD202X LED driver
+  name: KTD202X sample
+tests:
+  sample.drivers.led.ktd2026:
+    depends_on: arduino_i2c
+    build_only: true
+    tags: LED

samples/drivers/led/ktd202x/src/main.c

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+/*
+ * Copyright (c) 2025 Michael Estes
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/device.h>
+#include <errno.h>
+#include <zephyr/drivers/led.h>
+#include <zephyr/sys/util.h>
+#include <zephyr/kernel.h>
+
+#define LOG_LEVEL CONFIG_LOG_DEFAULT_LEVEL
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(main);
+
+#define NUM_LEDS        3
+#define HALF_BRIGHTNESS (LED_BRIGHTNESS_MAX / 2)
+#define BLINK_DELAY_ON  500
+#define BLINK_DELAY_OFF 500
+#define DELAY_TIME_MS   1000
+#define DELAY_TIME      K_MSEC(DELAY_TIME_MS)
+
+int main(void)
+{
+	const struct device *const led_dev = DEVICE_DT_GET_ANY(kinetic_ktd202x);
+	int i, ret;
+
+	if (!led_dev) {
+		LOG_ERR("No devices with compatible kinetic,ktd202x found");
+		return 0;
+	} else if (!device_is_ready(led_dev)) {
+		LOG_ERR("LED device %s is not ready", led_dev->name);
+		return 0;
+	}
+
+	LOG_INF("Found LED device %s", led_dev->name);
+	LOG_INF("Testing leds");
+
+	while (1) {
+		/* Turn on LEDs one by one */
+		for (i = 0; i < NUM_LEDS; i++) {
+			ret = led_on(led_dev, i);
+			if (ret < 0) {
+				return 0;
+			}
+
+			k_sleep(DELAY_TIME);
+		}
+
+		/* Turn off LEDs one by one */
+		for (i = 0; i < NUM_LEDS; i++) {
+			ret = led_off(led_dev, i);
+			if (ret < 0) {
+				return 0;
+			}
+
+			k_sleep(DELAY_TIME);
+		}
+
+		/* Set the brightness to half max of LEDs one by one */
+		for (i = 0; i < NUM_LEDS; i++) {
+			ret = led_set_brightness(led_dev, i, HALF_BRIGHTNESS);
+			if (ret < 0) {
+				return 0;
+			}
+
+			k_sleep(DELAY_TIME);
+		}
+
+		/* Turn off LEDs one by one */
+		for (i = 0; i < NUM_LEDS; i++) {
+			ret = led_off(led_dev, i);
+			if (ret < 0) {
+				return 0;
+			}
+
+			k_sleep(DELAY_TIME);
+		}
+	}
+	return 0;
+}