From ef6646379eb378c837b74f7b8bb786ee6d5b6382 Mon Sep 17 00:00:00 2001
From: Leandro Lanzieri <leandro.lanzieri@haw-hamburg.de>
Date: Tue, 9 Sep 2025 14:25:16 +0200
Subject: [PATCH 1/3] pkg/lvgl/lv_conf: fix documentation

---
 pkg/lvgl/include/lv_conf.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkg/lvgl/include/lv_conf.h b/pkg/lvgl/include/lv_conf.h
index 0eaf494033..305c63b57f 100644
--- a/pkg/lvgl/include/lv_conf.h
+++ b/pkg/lvgl/include/lv_conf.h
@@ -30,7 +30,7 @@ extern "C" {
  *====================*/
 
 /* Color depth:
- * - 1:  1 byte per pixel
+ * - 1:  1 bit per pixel
  * - 8:  RGB233
  * - 16: RGB565
  * - 32: ARGB8888

From d4e18fb555fc3cf9d73c0eac20d6c01047212b9d Mon Sep 17 00:00:00 2001
From: Leandro Lanzieri <leandro.lanzieri@haw-hamburg.de>
Date: Wed, 10 Sep 2025 13:39:20 +0200
Subject: [PATCH 2/3] sys/auto_init/screen/lvgl: check if display is present

---
 sys/auto_init/screen/auto_init_lvgl.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/auto_init/screen/auto_init_lvgl.c b/sys/auto_init/screen/auto_init_lvgl.c
index 3771b1f337..3ffa04f11a 100644
--- a/sys/auto_init/screen/auto_init_lvgl.c
+++ b/sys/auto_init/screen/auto_init_lvgl.c
@@ -50,6 +50,10 @@ void auto_init_lvgl(void)
     /* Only a single screen is supported by lvgl */
 #if !IS_USED(MODULE_LV_DRIVERS_SDL)
     disp_dev_reg_t *disp_dev = disp_dev_reg_find_screen(CONFIG_LVGL_SCREEN_DEFAULT);
+    if (disp_dev == NULL) {
+        puts("[auto_init_screen] error: no display device found\n");
+        return;
+    }
     s_screen.display = disp_dev->dev;
 #endif
 

From 1dae523f07f74f41e045d2926682ddac177e544f Mon Sep 17 00:00:00 2001
From: Leandro Lanzieri <leandro.lanzieri@haw-hamburg.de>
Date: Tue, 9 Sep 2025 14:26:01 +0200
Subject: [PATCH 3/3] pkg/lvgl: allow monochrome displays

---
 pkg/lvgl/contrib/lvgl.c    | 29 ++++++++++++++++++++++++++++-
 pkg/lvgl/include/lv_conf.h |  6 +++++-
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/pkg/lvgl/contrib/lvgl.c b/pkg/lvgl/contrib/lvgl.c
index 28d16a6f78..96347a3900 100644
--- a/pkg/lvgl/contrib/lvgl.c
+++ b/pkg/lvgl/contrib/lvgl.c
@@ -39,7 +39,11 @@
 #endif
 
 #ifndef LVGL_COLOR_BUF_SIZE
-#define LVGL_COLOR_BUF_SIZE                 (LV_HOR_RES_MAX * 10)
+#  if IS_USED(MODULE_U8G2_DISP_DEV)
+#    define LVGL_COLOR_BUF_SIZE                 (LV_HOR_RES_MAX * 10 * 8)
+#  else
+#    define LVGL_COLOR_BUF_SIZE                 (LV_HOR_RES_MAX * 10)
+#  endif
 #endif
 
 #ifndef CONFIG_LVGL_INACTIVITY_PERIOD_MS
@@ -134,6 +138,23 @@ static void _touch_read(lv_indev_drv_t *indev_driver, lv_indev_data_t *data)
 }
 #endif
 
+/* Pixel placement for monochrome displays where color depth is 1 bit, and each bit represents
+   a pixel */
+static void _monochrome_1bit_set_px_cb(lv_disp_drv_t *disp_drv, uint8_t *buf, lv_coord_t buf_w,
+                                       lv_coord_t x, lv_coord_t y, lv_color_t color, lv_opa_t opa)
+{
+    (void)disp_drv;
+    (void)opa;
+
+    uint16_t byte = (y * buf_w / 8) + (x / 8);
+    if (lv_color_brightness(color) > 128) {
+        (buf[byte]) |= (1 << (x % 8));
+    }
+    else {
+        (buf[byte]) &= ~(1 << (x % 8));
+    }
+}
+
 void lvgl_init(screen_dev_t *screen_dev)
 {
     lv_init();
@@ -164,6 +185,11 @@ void lvgl_init(screen_dev_t *screen_dev)
     disp_drv.ver_res = disp_dev_height(screen_dev->display);
 #endif
 
+    if (disp_dev_color_depth(screen_dev->display) == 1) {
+        disp_drv.full_refresh = 1;
+        disp_drv.set_px_cb = _monochrome_1bit_set_px_cb;
+    }
+
     lv_disp_drv_register(&disp_drv);
 
 #if IS_USED(MODULE_TOUCH_DEV)
@@ -208,5 +234,6 @@ void lvgl_run(void)
 void lvgl_wakeup(void)
 {
     thread_t *tcb = thread_get(_task_thread_pid);
+
     thread_flags_set(tcb, LVGL_THREAD_FLAG);
 }
diff --git a/pkg/lvgl/include/lv_conf.h b/pkg/lvgl/include/lv_conf.h
index 305c63b57f..f57f70ffdc 100644
--- a/pkg/lvgl/include/lv_conf.h
+++ b/pkg/lvgl/include/lv_conf.h
@@ -36,7 +36,11 @@ extern "C" {
  * - 32: ARGB8888
  */
 #ifndef LV_COLOR_DEPTH
-#define LV_COLOR_DEPTH     16
+#  if IS_USED(MODULE_U8G2_DISP_DEV)
+#    define LV_COLOR_DEPTH     1
+#  else
+#    define LV_COLOR_DEPTH     16
+#  endif
 #endif
 
 /* Swap the 2 bytes of RGB565 color.