refactor(display): Output/layer/battery thread safety.

* Submit widget updates to display queue.
* Use mutex to control access to shared state for widgets.

1 files changed, 36 insertions, 17 deletions

diff --git a/app/src/display/widgets/battery_status.c b/app/src/display/widgets/battery_status.c
index 309c3e9..7503c61 100644
--- a/app/src/display/widgets/battery_status.c
+++ b/app/src/display/widgets/battery_status.c
@@ -4,11 +4,13 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <kernel.h>
 #include <bluetooth/services/bas.h>
 
 #include <logging/log.h>
 LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
+#include <zmk/display.h>
 #include <zmk/display/widgets/battery_status.h>
 #include <zmk/usb.h>
 #include <zmk/events/usb_conn_state_changed.h>
@@ -33,12 +35,20 @@ void battery_status_init() {
     lv_style_set_text_line_space(&label_style, LV_STATE_DEFAULT, 1);
 }
 
-void set_battery_symbol(lv_obj_t *label) {
+struct battery_status_state {
+    uint8_t level;
+#if IS_ENABLED(CONFIG_USB)
+    bool usb_present;
+#endif
+};
+
+static void set_battery_symbol(lv_obj_t *label, struct battery_status_state state) {
     char text[2] = "  ";
-    uint8_t level = bt_bas_get_battery_level();
+
+    uint8_t level = state.level;
 
 #if IS_ENABLED(CONFIG_USB)
-    if (zmk_usb_is_powered()) {
+    if (state.usb_present) {
         strcpy(text, LV_SYMBOL_CHARGE);
     }
 #endif /* IS_ENABLED(CONFIG_USB) */
@@ -57,32 +67,41 @@ void set_battery_symbol(lv_obj_t *label) {
     lv_label_set_text(label, text);
 }
 
+void battery_status_update_cb(struct battery_status_state state) {
+    struct zmk_widget_battery_status *widget;
+    SYS_SLIST_FOR_EACH_CONTAINER(&widgets, widget, node) { set_battery_symbol(widget->obj, state); }
+}
+
+static struct battery_status_state battery_status_get_state(const zmk_event_t *eh) {
+    return (struct battery_status_state) {
+        .level = bt_bas_get_battery_level(),
+#if IS_ENABLED(CONFIG_USB)
+        .usb_present = zmk_usb_is_powered(),
+#endif /* IS_ENABLED(CONFIG_USB) */
+    };
+}
+
+ZMK_DISPLAY_WIDGET_LISTENER(widget_battery_status, struct battery_status_state,
+                            battery_status_update_cb, battery_status_get_state)
+
+ZMK_SUBSCRIPTION(widget_battery_status, zmk_battery_state_changed);
+#if IS_ENABLED(CONFIG_USB)
+ZMK_SUBSCRIPTION(widget_battery_status, zmk_usb_conn_state_changed);
+#endif /* IS_ENABLED(CONFIG_USB) */
+
 int zmk_widget_battery_status_init(struct zmk_widget_battery_status *widget, lv_obj_t *parent) {
     battery_status_init();
     widget->obj = lv_label_create(parent, NULL);
     lv_obj_add_style(widget->obj, LV_LABEL_PART_MAIN, &label_style);
 
     lv_obj_set_size(widget->obj, 40, 15);
-    set_battery_symbol(widget->obj);
 
     sys_slist_append(&widgets, &widget->node);
 
+    widget_battery_status_init();
     return 0;
 }
 
 lv_obj_t *zmk_widget_battery_status_obj(struct zmk_widget_battery_status *widget) {
-    LOG_DBG("Label: %p", widget->obj);
     return widget->obj;
 }
-
-int battery_status_listener(const zmk_event_t *eh) {
-    struct zmk_widget_battery_status *widget;
-    SYS_SLIST_FOR_EACH_CONTAINER(&widgets, widget, node) { set_battery_symbol(widget->obj); }
-    return ZMK_EV_EVENT_BUBBLE;
-}
-
-ZMK_LISTENER(widget_battery_status, battery_status_listener)
-ZMK_SUBSCRIPTION(widget_battery_status, zmk_battery_state_changed);
-#if IS_ENABLED(CONFIG_USB)
-ZMK_SUBSCRIPTION(widget_battery_status, zmk_usb_conn_state_changed);
-#endif /* IS_ENABLED(CONFIG_USB) */