samples: modules: u8g2: add u8x8 samples for u8g2 module

Add sample for u8g2 module.

hello_u8x8 sample show how to use u8x8 mode.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

samples/modules/u8g2/hello_u8x8/CMakeLists.txt

@@ -0,0 +1,8 @@
+# Copyright (c) 2023 TOKITA Hiroshi
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(hello_u8x8)
+
+target_sources(app PRIVATE src/main.c)

samples/modules/u8g2/hello_u8x8/README.rst

@@ -0,0 +1,26 @@
+.. _hello_u8x8:
+
+U8x8 sample
+###########
+
+Overview
+********
+
+This sample is U8G2 library demo.
+This sample shows how to use U8x8 mode that not use offscreen buffer mode.
+
+Requirements
+************
+
+This sample require display device.
+
+Building and Running
+********************
+
+To build and flash the sample for the :ref:`frdm_k64f`:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/module/u8g2/hello_u8x8
+   :board: frdm_k64f
+   :goals: build flash
+   :compact:

samples/modules/u8g2/hello_u8x8/boards/native_posix_64.conf

@@ -0,0 +1 @@
+CONFIG_SDL_DISPLAY_DEFAULT_PIXEL_FORMAT_MONO10=y

samples/modules/u8g2/hello_u8x8/prj.conf

@@ -0,0 +1,4 @@
+CONFIG_HEAP_MEM_POOL_SIZE=16384
+CONFIG_LOG=y
+CONFIG_DISPLAY=y
+CONFIG_U8G2=y

samples/modules/u8g2/hello_u8x8/sample.yaml

@@ -0,0 +1,7 @@
+sample:
+  description: U8x8 Sample application
+  name: hello_u8x8
+tests:
+  sample.modules.u8g2.hello_u8x8.sdl:
+    platform_allow: native_posix_64
+    tags: display

samples/modules/u8g2/hello_u8x8/src/main.c

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2023 TOKITA Hiroshi
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <u8g2.h>
+#include <u8g2_zephyr.h>
+
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/display.h>
+
+#ifdef CONFIG_ARCH_POSIX
+#include "posix_board_if.h"
+#endif
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(hello_u8x8, LOG_LEVEL_INF);
+
+int main(void)
+{
+	const struct device *dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_display));
+	u8x8_t *u8x8;
+
+	if (!device_is_ready(dev)) {
+		LOG_ERR("Device %s not found. Aborting sample.", dev->name);
+		return 0;
+	}
+
+	if (display_set_pixel_format(dev, PIXEL_FORMAT_MONO10) != 0) {
+		LOG_ERR("Failed to set required pixel format.");
+		return 0;
+	}
+
+	if (display_blanking_off(dev) != 0) {
+		LOG_ERR("Failed to turn off display blanking.");
+		return 0;
+	}
+
+	u8x8 = u8x8_SetupZephyr(dev);
+	if (!u8x8) {
+		LOG_ERR("Failed to allocate u8x8 instance.");
+		return 0;
+	}
+
+	u8x8_InitDisplay(u8x8);
+	u8x8_ClearDisplay(u8x8);
+
+	u8x8_SetFont(u8x8, u8x8_font_amstrad_cpc_extended_f);
+	u8x8_DrawString(u8x8, 0, 0, "Hello World!");
+	u8x8_Draw1x2String(u8x8, 0, 1, "Hello World!");
+	u8x8_Draw2x2String(u8x8, 0, 3, "Hello World!");
+
+#ifdef CONFIG_ARCH_POSIX
+	posix_exit_main(0);
+#endif
+
+	return 0;
+}