feat(app/hmi-generic): Add new HMI application

HMI generic application implements some basic functionality of a HMI
device, specifically:

- drawing on a display/framebuffer device
- managing keypad and buttons
- sensing proximity of the user
- outputting sound using a speaker
- communicating over a suitable interface/bus

It should be fully configurable using Kconfig (not yet the case).

Author: iqyx

applications/hmi-generic/Kconfig

@@ -0,0 +1,11 @@
+config APP_HMI_GENERIC
+	bool "A generic HMI application with LCD, presence detection, speaker, keyboard"
+
+menu "Generic HMI application config"
+	depends on APP_HMI_GENERIC
+
+	config APP_NAME
+		string
+		default "hmi-generic"
+
+endmenu

applications/hmi-generic/SConscript

@@ -0,0 +1,9 @@
+Import("env")
+Import("conf")
+Import("objs")
+
+objs.append(env.Object(source = [
+	File("app.c"),
+]))
+env.Append(CPPPATH = [Dir(".")])
+

applications/hmi-generic/app.c

@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Generic HMI implementation
+ *
+ * Copyright (c) 2025, Marek Koza (qyx@krtko.org)
+ * All rights reserved.
+ */
+
+#include <main.h>
+#include "app.h"
+
+#define MODULE_NAME "hmi"
+
+
+static void com_task(void *p) {
+	App *self = p;
+
+	struct nbus_socket *socket = nbus_socket_allocate(&nbus);
+	while (true) {
+		uint8_t local_id[] = {0x00, 0x00, 0x00, 0x10};
+		nbus_socket_bind(socket, local_id, 1);
+
+		struct datagram_msg rxmsg = {0};
+		static uint8_t packet_buffer[1024];
+		size_t len = sizeof(packet_buffer);
+
+		if (socket->datagram.vmt->read(&socket->datagram, packet_buffer, &len, &rxmsg) == DATAGRAM_RET_OK) {
+			uint32_t offset = packet_buffer[0] << 24 | packet_buffer[1] << 16 | packet_buffer[2] << 8 | packet_buffer[3];
+			len -= 4;
+
+			if ((offset + len) > 9600) {
+				continue;
+			}
+			self->fb->vmt->write(self->fb, offset, packet_buffer + 4, len, FB_MODE_G2);
+
+			if ((offset + len) == 9600) {
+				self->fb->vmt->flush(self->fb);
+			}
+		}
+
+	}
+	nbus_socket_release(&nbus, socket);
+	vTaskDelete(NULL);
+}
+
+
+static void input_task(void *p) {
+	App *self = p;
+
+
+	while (true) {
+
+		vTaskDelay(1000);
+	}
+	vTaskDelete(NULL);
+}
+
+
+app_ret_t app_init(App *self) {
+	memset(self, 0, sizeof(App));
+
+	self->fb = NULL;
+	if (iservicelocator_query_type_id(locator, ISERVICELOCATOR_TYPE_FB, 0, (Interface **)&self->fb) != ISERVICELOCATOR_RET_OK) {
+		u_log(system_log, LOG_TYPE_ERROR, U_LOG_MODULE_PREFIX("no framebuffer device found"));
+		return APP_RET_FAILED;
+	}
+
+	/* Get any i2c available. Allow configuration in the future (along with input devices). */
+	self->i2c = NULL;
+	if (iservicelocator_query_type_id(locator, ISERVICELOCATOR_TYPE_I2C, 0, (Interface **)&self->i2c) != ISERVICELOCATOR_RET_OK) {
+		u_log(system_log, LOG_TYPE_ERROR, U_LOG_MODULE_PREFIX("no suitable i2c device found"));
+		return APP_RET_FAILED;
+	}
+
+	xTaskCreate(com_task, "hmi-com", configMINIMAL_STACK_SIZE + 256, (void *)self, 1, &(self->com_task));
+	if (self->com_task == NULL) {
+		u_log(system_log, LOG_TYPE_ERROR, U_LOG_MODULE_PREFIX("cannot create application com task"));
+		goto err;
+	}
+
+	xTaskCreate(input_task, "hmi-input", configMINIMAL_STACK_SIZE + 128, (void *)self, 1, &(self->input_task));
+	if (self->input_task == NULL) {
+		u_log(system_log, LOG_TYPE_ERROR, U_LOG_MODULE_PREFIX("cannot create application input task"));
+		goto err;
+	}
+
+
+	return APP_RET_OK;
+err:
+	return APP_RET_FAILED;
+}
+
+
+app_ret_t app_free(App *self) {
+	return APP_RET_OK;
+}

applications/hmi-generic/app.h

@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Generic HMI implementation
+ *
+ * Copyright (c) 2025, Marek Koza (qyx@krtko.org)
+ * All rights reserved.
+ */
+
+#pragma once
+
+#include <interfaces/datagram.h>
+#include <interfaces/fb.h>
+#include <interfaces/i2c-bus.h>
+#include <services/nbus2/nbus2.h>
+
+
+typedef enum {
+	APP_RET_OK = 0,
+	APP_RET_FAILED,
+} app_ret_t;
+
+typedef struct {
+	TaskHandle_t com_task;
+	TaskHandle_t input_task;
+	Fb *fb;
+	I2cBus *i2c;
+} App;
+
+
+app_ret_t app_init(App *self);
+app_ret_t app_free(App *self);
+