tests/pkg_lvgl_touch: add lvgl sample with touch capabilities

tests/pkg_lvgl_touch/Makefile

@@ -0,0 +1,15 @@
+BOARD ?= stm32f429i-disc1
+include ../Makefile.tests_common
+
+# No interactive_sync
+DISABLE_MODULE += test_utils_interactive_sync
+
+USEPKG += lvgl
+USEMODULE += lvgl_contrib
+USEMODULE += ili9341
+
+# Add touch capabilities
+USEMODULE += lvgl_contrib_touch
+USEMODULE += stmpe811
+
+include $(RIOTBASE)/Makefile.include

tests/pkg_lvgl_touch/Makefile.ci

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+BOARD_INSUFFICIENT_MEMORY := \
+    blackpill \
+    bluepill \
+    i-nucleo-lrwan1 \
+    nucleo-f031k6 \
+    nucleo-f042k6 \
+    nucleo-f302r8 \
+    nucleo-f303k8 \
+    nucleo-f334r8 \
+    nucleo-l031k6 \
+    nucleo-l053r8 \
+    saml10-xpro \
+    saml11-xpro \
+    stm32f030f4-demo \
+    stm32f0discovery \
+    stm32l0538-disco \
+    #

tests/pkg_lvgl_touch/README.md

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+LittlevGL sample application
+============================
+
+This application shows a usage of LittlevGL with touch capabilities.
+
+### Flashing the application
+
+The application works without modification on the stm32f429i-disc1 board. To
+build, flash and run the application for this board, just use:
+
+```
+make BOARD=stm32f429i-disc1 -C tests/pkg_lvgl_touch flash
+```
+
+### Expected result
+
+The application simply displays a button that can be clicked. Each time the
+button is clicked, the message "Button clicked!" is displayed in the terminal.

tests/pkg_lvgl_touch/main.c

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+/*
+ * Copyright (C) 2020 Inria
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     tests
+ * @{
+ *
+ * @file
+ * @brief       LittlevGL example application with clickable button
+ *
+ * @author      Alexandre Abadie <alexandre.abadie@inria.fr>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+
+#include "lvgl/lvgl.h"
+#include "lvgl_riot.h"
+
+#include "ili9341.h"
+#include "ili9341_params.h"
+#include "disp_dev.h"
+#include "ili9341_disp_dev.h"
+
+#include "stmpe811.h"
+#include "stmpe811_params.h"
+#include "touch_dev.h"
+#include "stmpe811_touch_dev.h"
+
+#include "screen_dev.h"
+
+static screen_dev_t s_screen;
+static ili9341_t s_disp_dev;
+static stmpe811_t s_touch_dev;
+
+static void _stmpe811_event_cb(void *arg)
+{
+    (void)arg;
+    lvgl_wakeup();
+}
+
+static void btn_event_cb(lv_obj_t * btn, lv_event_t event)
+{
+    (void)btn;
+    if (event == LV_EVENT_CLICKED) {
+        puts("Button clicked!");
+    }
+}
+
+int main(void)
+{
+    /* Configure the generic display driver interface */
+    s_screen.display = (disp_dev_t *)&s_disp_dev;
+    s_screen.display->driver = &ili9341_disp_dev_driver;
+
+    /* Initialize the concrete display driver */
+    ili9341_init(&s_disp_dev, &ili9341_params[0]);
+
+    /* Configure the generic touch driver interface */
+    s_screen.touch = (touch_dev_t *)&s_touch_dev;
+    s_screen.touch->driver = &stmpe811_touch_dev_driver;
+
+    /* Initialize the concrete touch driver */
+    stmpe811_init(&s_touch_dev, &stmpe811_params[0], _stmpe811_event_cb, NULL);
+
+    /* Initialize lvgl with the generic screen */
+    lvgl_init(&s_screen);
+
+    /* Add a button to the current screen */
+    lv_obj_t * btn = lv_btn_create(lv_scr_act(), NULL);
+
+    /* Set the button position and size */
+    lv_coord_t x_size = 100;
+    lv_coord_t y_size = 50;
+    lv_coord_t x_pos = (disp_dev_width(s_screen.display) - x_size) / 2;
+    lv_coord_t y_pos = (disp_dev_height(s_screen.display) - y_size) / 2;
+    lv_obj_set_pos(btn, x_pos, y_pos);
+    lv_obj_set_size(btn, 100, 50);
+
+    /*Assign a callback to the button*/
+    lv_obj_set_event_cb(btn, btn_event_cb);
+
+    /* Add a label to the button */
+    lv_obj_t * label = lv_label_create(btn, NULL);
+    lv_label_set_text(label, "Click me");
+
+    return 0;
+}