pkg/lvgl: add optional touch capability via screen generic API

pkg/lvgl/Makefile.dep

@@ -12,6 +12,10 @@ ifneq (,$(filter lvgl_contrib,$(USEMODULE)))
   USEMODULE += xtimer
 endif
 
+ifneq (,$(filter lvgl_contrib_touch,$(USEMODULE)))
+  USEMODULE += touch_dev
+endif
+
 # lvgl is not compatible with non 32bit platforms
 # Building lv_misc triggers the error:
 # "left shift count >= width of type [-Werror=shift-count-overflow]"

pkg/lvgl/Makefile.include

@@ -31,3 +31,6 @@ CFLAGS += -DLVGL_TASK_THREAD_PRIO=$(LVGL_TASK_THREAD_PRIO)
 
 # lvgl module is not a concrete module, so declare it as a pseudomodule
 PSEUDOMODULES += lvgl
+
+# touch capabilities are available via a pseudomodule
+PSEUDOMODULES += lvgl_contrib_touch

pkg/lvgl/contrib/lvgl.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019 Inria
+ * Copyright (C) 2019-2020 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
@@ -17,6 +17,8 @@
  * @}
  */
 
+#include <assert.h>
+
 #include "thread.h"
 
 #include "xtimer.h"
@@ -25,7 +27,8 @@
 #include "lvgl/lvgl.h"
 #include "lv_conf.h"
 #include "lvgl_riot.h"
-#include "disp_dev.h"
+
+#include "screen_dev.h"
 
 #ifndef LVGL_TASK_THREAD_PRIO
 #define LVGL_TASK_THREAD_PRIO       (THREAD_PRIORITY_MAIN + 1)
@@ -52,7 +55,9 @@ static kernel_pid_t _task_thread_pid;
 
 static lv_disp_buf_t disp_buf;
 static lv_color_t buf[LVGL_COLOR_BUF_SIZE];
-static disp_dev_t *_dev = NULL;
+
+static screen_dev_t *_screen_dev = NULL;
+
 
 static void *_task_thread(void *arg)
 {
@@ -80,11 +85,11 @@ static void *_task_thread(void *arg)
 
 static void _disp_map(lv_disp_drv_t *drv, const lv_area_t *area, lv_color_t *color_p)
 {
-    if (!_dev) {
+    if (!_screen_dev->display) {
         return;
     }
 
-    disp_dev_map(_dev, area->x1, area->x2, area->y1, area->y2,
+    disp_dev_map(_screen_dev->display, area->x1, area->x2, area->y1, area->y2,
                  (const uint16_t *)color_p);
 
     LOG_DEBUG("[lvgl] flush display\n");
@@ -92,22 +97,63 @@ static void _disp_map(lv_disp_drv_t *drv, const lv_area_t *area, lv_color_t *col
     lv_disp_flush_ready(drv);
 }
 
-void lvgl_init(disp_dev_t *dev)
+#ifdef MODULE_TOUCH_DEV
+/* adapted from https://github.com/lvgl/lvgl/tree/v6.1.2#add-littlevgl-to-your-project */
+static bool _touch_read(lv_indev_drv_t *indev_driver, lv_indev_data_t *data)
+{
+    if (!_screen_dev->touch) {
+        return false;
+    }
+
+    (void)indev_driver;
+    static lv_coord_t last_x = 0;
+    static lv_coord_t last_y = 0;
+
+    touch_t positions[1];
+    uint8_t touches = touch_dev_touches(_screen_dev->touch, positions, 1);
+
+    /* Save the state and save the pressed coordinates */
+    data->state = (touches > 0) ? LV_INDEV_STATE_PR : LV_INDEV_STATE_REL;
+    if (data->state == LV_INDEV_STATE_PR) {
+        last_x = positions[0].x;
+        last_y = positions[0].y;
+    }
+
+    /* Set the coordinates (if released use the last pressed coordinates) */
+    data->point.x = last_x;
+    data->point.y = last_y;
+
+    return false;
+}
+#endif
+
+void lvgl_init(screen_dev_t *screen_dev)
 {
-    _dev = dev;
     lv_init();
+    _screen_dev = screen_dev;
+    assert(screen_dev->display);
+
     lv_disp_drv_t disp_drv;
     lv_disp_drv_init(&disp_drv);
     /* Configure horizontal and vertical resolutions based on the
        underlying display device parameters */
-    disp_drv.hor_res = disp_dev_width(dev);
+    disp_drv.hor_res = disp_dev_width(screen_dev->display);
-    disp_drv.ver_res = disp_dev_height(dev);
+    disp_drv.ver_res = disp_dev_height(screen_dev->display);
 
     disp_drv.flush_cb = _disp_map;
     disp_drv.buffer = &disp_buf;
     lv_disp_drv_register(&disp_drv);
     lv_disp_buf_init(&disp_buf, buf, NULL, LVGL_COLOR_BUF_SIZE);
 
+#ifdef MODULE_TOUCH_DEV
+    assert(screen_dev->touch);
+    lv_indev_drv_t indev_drv;
+    lv_indev_drv_init(&indev_drv);
+    indev_drv.type = LV_INDEV_TYPE_POINTER;
+    indev_drv.read_cb = _touch_read;
+    lv_indev_drv_register(&indev_drv);
+#endif
+
     lv_task_handler();
     _task_thread_pid = thread_create(_task_thread_stack, sizeof(_task_thread_stack),
                                      LVGL_TASK_THREAD_PRIO, THREAD_CREATE_STACKTEST,

pkg/lvgl/include/lvgl_riot.h

@@ -19,7 +19,7 @@
 #ifndef LVGL_RIOT_H
 #define LVGL_RIOT_H
 
-#include "disp_dev.h"
+#include "screen_dev.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -28,9 +28,9 @@ extern "C" {
 /**
  * @brief   Initialize the lvgl display engine
  *
- * @param[in] dev   Pointer to the generic display device
+ * @param[in] screen_dev   Pointer to the generic screen device
  */
-void lvgl_init(disp_dev_t *dev);
+void lvgl_init(screen_dev_t *screen_dev);
 
 /**
  * @brief   Wakeup lvgl when inactive