tests/cst816s: Add basic touch screen test

tests/driver_cst816s/Makefile

@@ -0,0 +1,6 @@
+include ../Makefile.tests_common
+
+USEMODULE += cst816s
+USEMODULE += core_thread_flags
+
+include $(RIOTBASE)/Makefile.include

tests/driver_cst816s/main.c

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2020 Koen Zandberg
+ *
+ * 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       Test application for the CST816S touch screen driver
+ *
+ * @author      Koen Zandberg <koen@bergzand.net>
+ *
+ * @}
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "cst816s_params.h"
+#include "cst816s.h"
+#include "thread.h"
+#include "thread_flags.h"
+
+#define CST816S_THREAD_FLAG     (1 << 8)
+#define CST816S_NUM_TOUCHES     5
+
+static void _cb(void *arg)
+{
+    kernel_pid_t *pid = arg;
+    thread_flags_set((thread_t *)sched_threads[*pid], CST816S_THREAD_FLAG);
+}
+
+static void _dump_cst816s(cst816s_t *dev)
+{
+    puts("Reading data:");
+    cst816s_touch_data_t touches;
+    if (cst816s_read(dev, &touches) == 0) {
+        printf("Touch at %03u, %03u with gesture type \"%s\"\n", touches.x,
+               touches.y, cst816s_gesture_str[touches.gesture]);
+    }
+    else {
+        puts("Device not responding");
+    }
+}
+
+int main(void)
+{
+    cst816s_t dev;
+
+    kernel_pid_t pid = thread_getpid();
+
+    puts("CST816S test application\n");
+    cst816s_init(&dev, &cst816s_params[0], _cb, &pid);
+
+    while (1) {
+        thread_flags_t flags = thread_flags_wait_any(CST816S_THREAD_FLAG);
+        if (flags & CST816S_THREAD_FLAG) {
+            _dump_cst816s(&dev);
+        }
+    }
+    return 0;
+}