samples: mgmt/osdp: Add new OSDP PD sample

This commit adds a PD sample for drivers/osdp. It receives OSDP commands
and prints a message to console.

Signed-off-by: Siddharth Chandrasekaran <siddharth@embedjournal.com>

samples/subsys/mgmt/osdp/CMakeLists.txt

@@ -0,0 +1,12 @@
+#
+# Copyright (c) 2020 Siddharth Chandrasekaran <siddharth@embedjournal.com>
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+cmake_minimum_required(VERSION 3.13.1)
+include($ENV{ZEPHYR_BASE}/cmake/app/boilerplate.cmake NO_POLICY_SCOPE)
+
+project(osdp_sample)
+
+target_sources(app PRIVATE src/main.c)

samples/subsys/mgmt/osdp/README.rst

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+.. _osdp-sample:
+
+OSDP
+####
+
+OSDP describes the communication interface one or more Peripheral Devices (PD)
+to a Control Panel (CP). The specification describes the protocol
+implementation over a two-wire RS-485 multi-drop serial communication channel.
+Nevertheless, this protocol can be used to transfer secure byte stream over any
+physical channel in low memory embedded devices.
+
+Although OSDP is steered towards the Access and Security industries, it can be
+used as a general communication protocol for devices in a secure way without
+too much resource requirements. The security is not top-notch (AES-128) but it
+is reasonable enough, given that the alternative is no security at all.
+
+OSDP Supports the control of the following components on a PD:
+   - LED
+   - Buzzer
+   - Keypad
+   - Output (GPIOs)
+   - Input Control (GPIOs)
+   - Displays
+   - Device status (tamper, power, etc.,)
+   - Card Reader
+   - Fingerprint Reader

samples/subsys/mgmt/osdp/prj.conf

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+#
+# Copyright (c) 2020 Siddharth Chandrasekaran <siddharth@embedjournal.com>
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+CONFIG_PRINTK=y
+CONFIG_LOG=y
+
+# OSDP config
+CONFIG_OSDP=y

samples/subsys/mgmt/osdp/src/main.c

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+/*
+ * Copyright (c) 2020 Siddharth Chandrasekaran <siddharth@embedjournal.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr.h>
+#include <device.h>
+#include <drivers/gpio.h>
+#include <mgmt/osdp.h>
+
+/* 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)
+#if DT_PHA_HAS_CELL(LED0_NODE, gpios, flags)
+#define FLAGS   DT_GPIO_FLAGS(LED0_NODE, gpios)
+#endif
+#else
+#error "BOARD does not define a debug LED"
+#define LED0    ""
+#define PIN     0
+#endif
+
+#ifndef FLAGS
+#define FLAGS   0
+#endif
+
+#define SLEEP_TIME_MS                  10
+
+int cmd_handler(struct osdp_cmd *p)
+{
+	printk("App received command %d\n", p->id);
+	return 0;
+}
+
+void main(void)
+{
+	int ret, led_state;
+	uint32_t cnt = 0;
+	struct device *dev;
+	struct osdp_cmd cmd;
+
+	dev = device_get_binding(LED0);
+	if (dev == NULL) {
+		printk("Failed to get LED0 binding\n");
+		return;
+	}
+
+	ret = gpio_pin_configure(dev, PIN, GPIO_OUTPUT_ACTIVE | FLAGS);
+	if (ret < 0) {
+		printk("Failed to configure gpio pin\n");
+		return;
+	}
+
+	led_state = 0;
+	while (1) {
+		if ((cnt & 0x7f) == 0x7f) {
+			/* show a sign of life */
+			led_state = !led_state;
+		}
+		if (osdp_pd_get_cmd(&cmd) == 0) {
+			cmd_handler(&cmd);
+		}
+		gpio_pin_set(dev, PIN, led_state);
+		k_msleep(SLEEP_TIME_MS);
+		cnt++;
+	}
+}