Work on zephyr support

examples/zephyr-blink/include/README

@@ -0,0 +1,39 @@
+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with `.h'.
+It is most portable to use only letters, digits, dashes, and underscores in
+header file names, and at most one dot.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

examples/zephyr-blink/lib/README

@@ -0,0 +1,46 @@
+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into executable file.
+
+The source code of each library should be placed in a an own separate directory
+("lib/your_library_name/[here are source files]").
+
+For example, see a structure of the following two libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+and a contents of `src/main.c`:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+PlatformIO Library Dependency Finder will find automatically dependent
+libraries scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

examples/zephyr-blink/platformio.ini

@@ -0,0 +1,14 @@
+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:pico]
+platform = https://github.com/maxgerhardt/platform-raspberrypi.git
+board = pico
+framework = zephyr

examples/zephyr-blink/src/main.c

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr.h>
+#include <device.h>
+#include <devicetree.h>
+#include <drivers/gpio.h>
+
+/* 1000 msec = 1 sec */
+#define SLEEP_TIME_MS   1000
+
+/* The devicetree node identifier for the "led0" alias. */
+#define LED0_NODE DT_ALIAS(led0)
+
+#if DT_NODE_HAS_STATUS(LED0_NODE, okay)
+#define LED0	DT_GPIO_LABEL(LED0_NODE, gpios)
+#define PIN	DT_GPIO_PIN(LED0_NODE, gpios)
+#define FLAGS	DT_GPIO_FLAGS(LED0_NODE, gpios)
+#else
+/* A build error here means your board isn't set up to blink an LED. */
+#error "Unsupported board: led0 devicetree alias is not defined"
+#define LED0	""
+#define PIN	0
+#define FLAGS	0
+#endif
+
+void main(void)
+{
+	const struct device *dev;
+	bool led_is_on = true;
+	int ret;
+
+	dev = device_get_binding(LED0);
+	if (dev == NULL) {
+		return;
+	}
+
+	ret = gpio_pin_configure(dev, PIN, GPIO_OUTPUT_ACTIVE | FLAGS);
+	if (ret < 0) {
+		return;
+	}
+
+	while (1) {
+		gpio_pin_set(dev, PIN, (int)led_is_on);
+		led_is_on = !led_is_on;
+		k_msleep(SLEEP_TIME_MS);
+	}
+}

examples/zephyr-blink/test/README

@@ -0,0 +1,11 @@
+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html

examples/zephyr-blink/zephyr/CMakeLists.txt

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(blinky)
+
+target_sources(app PRIVATE ../src/main.c)

examples/zephyr-blink/zephyr/prj.conf

@@ -0,0 +1 @@
+# nothing here