samples: boards: add sample for Altera Nios-II PIO core

Add a sample application for Nios-II PIO core on Altera MAX10 board.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>

samples/boards/altera_max10/altera_max10.rst

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+.. _altera_max10_devkit-samples:
+
+Altera MAX10 Development Kit Samples
+#####################################
+
+.. toctree::
+   :maxdepth: 1
+   :glob:
+
+   **/*

samples/boards/altera_max10/pio/CMakeLists.txt

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+include($ENV{ZEPHYR_BASE}/cmake/app/boilerplate.cmake NO_POLICY_SCOPE)
+project(NONE)
+
+target_sources(app PRIVATE src/main.c)

samples/boards/altera_max10/pio/README.rst

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+.. _altera_max10_pio-sample:
+
+Altera Nios-II PIO sample
+###############################
+
+Overview
+********
+This sample application demonstrates the usage of Nios-II
+Parallel Input/Output (PIO) soft IP by controlling the LEDs
+on an Altera MAX10 board.
+
+Requirements
+************
+
+This application uses an Altera MAX10 development board for the demo.
+
+Building
+********
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/boards/altera_max10/pio
+   :board: altera_max10
+   :goals: build
+   :compact:
+
+Sample Output
+=============
+
+nios2 core output
+-----------------
+
+.. code-block:: console
+
+  Turning off all LEDs
+  Turn On LED[0]
+  Turn On LED[1]
+  Turn On LED[2]
+  Turn On LED[3]
+  Turning on all LEDs

samples/boards/altera_max10/pio/prj.conf

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+CONFIG_GPIO=y
+CONFIG_GPIO_ALTERA_NIOS2=y
+CONFIG_GPIO_ALTERA_NIOS2_OUTPUT=y
+CONFIG_GPIO_ALTERA_NIOS2_OUTPUT_DEV_NAME="PIO_OUTPUT"

samples/boards/altera_max10/pio/sample.yaml

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+sample:
+  description: Sample application to verify the Nios-II based
+    PIO soft IP block.
+  name: Nios-II Parallel Input/Output (PIO)
+tests:
+  test:
+    build_only: true
+    platform_whitelist: altera_max10
+    tags: samples pio

samples/boards/altera_max10/pio/src/main.c

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+/*
+ * Copyright (c) 2017 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr.h>
+#include <device.h>
+#include <gpio.h>
+#include <misc/printk.h>
+#include <misc/util.h>
+
+/* GPIO driver name */
+#define GPIO_DRV_NAME	CONFIG_GPIO_ALTERA_NIOS2_OUTPUT_DEV_NAME
+
+/* PIO pins[0:3] are wired to LED's */
+#define LED_PINS_WIRED		4
+#define LED_PIN_MASK		0xf
+
+void main(void)
+{
+	struct device *gpio_dev;
+	int i, ret;
+
+	gpio_dev = device_get_binding(GPIO_DRV_NAME);
+	if (!gpio_dev) {
+		printk("Cannot find %s!\n", GPIO_DRV_NAME);
+		return;
+	}
+
+	/* Setup GPIO output */
+	ret = gpio_port_configure(gpio_dev, GPIO_DIR_OUT);
+	if (ret) {
+		printk("Error configuring GPIO PORT\n");
+	}
+
+	/*
+	 * Note: the LED's are connected in inverse logic
+	 * to the Nios-II PIO core.
+	 */
+	printk("Turning off all LEDs\n");
+	ret = gpio_port_write(gpio_dev, LED_PIN_MASK);
+	if (ret) {
+		printk("Error set GPIO port\n");
+	}
+	k_sleep(MSEC_PER_SEC * 5);
+
+	for (i = 0; i < LED_PINS_WIRED; i++) {
+		printk("Turn On LED[%d]\n", i);
+		ret = gpio_port_write(gpio_dev, LED_PIN_MASK & ~(1 << i));
+		if (ret) {
+			printk("Error in seting GPIO port\n");
+		}
+
+		k_sleep(MSEC_PER_SEC * 5);
+	}
+
+	printk("Turning on all LEDs\n");
+	ret = gpio_port_write(gpio_dev, 0x0);
+	if (ret) {
+		printk("Error set GPIO port\n");
+	}
+}