feat(underglow): Add battery level behavior to per-key RGB

app/CMakeLists.txt

@@ -93,6 +93,7 @@ target_sources_ifdef(CONFIG_ZMK_RGB_UNDERGLOW app PRIVATE src/behaviors/behavior
 if (CONFIG_ZMK_HID_INDICATORS)
   target_sources_ifdef(CONFIG_ZMK_RGB_UNDERGLOW app PRIVATE src/behaviors/behavior_underglow_indicators.c)
 endif()
+target_sources_ifdef(CONFIG_ZMK_RGB_UNDERGLOW app PRIVATE src/behaviors/behavior_underglow_battery.c)
 target_sources_ifdef(CONFIG_ZMK_RGB_UNDERGLOW app PRIVATE src/events/underglow_color_changed.c)
 target_sources_ifdef(CONFIG_ZMK_BACKLIGHT app PRIVATE src/behaviors/behavior_backlight.c)
 

app/dts/behaviors.dtsi

@@ -30,3 +30,4 @@
 #include <behaviors/mouse_keys.dtsi>
 #include <behaviors/ug_color.dtsi>
 #include <behaviors/ug_indicators.dtsi>
+#include <behaviors/ug_battery.dtsi>

app/dts/behaviors/ug_battery.dtsi

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2024 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+/ {
+    behaviors {
+        ug_b2: ugbat20 {
+            compatible = "zmk,behavior-underglow-battery";
+            threshold = <20>;
+            #binding-cells = <2>;
+            display-name = "Underglow Battery level 20%";
+        };
+        ug_b4: ugbat40 {
+            compatible = "zmk,behavior-underglow-battery";
+            threshold = <40>;
+            #binding-cells = <2>;
+            display-name = "Underglow Battery level 40%";
+        };
+        ug_b6: ugbat60 {
+            compatible = "zmk,behavior-underglow-battery";
+            threshold = <60>;
+            #binding-cells = <2>;
+            display-name = "Underglow Battery level 60%";
+        };
+        ug_b8: ugbat80 {
+            compatible = "zmk,behavior-underglow-battery";
+            threshold = <80>;
+            #binding-cells = <2>;
+            display-name = "Underglow Battery level 80%";
+        };
+    };
+};

app/dts/bindings/behaviors/zmk,behavior-underglow-battery.yaml

@@ -0,0 +1,12 @@
+# Copyright (c) 2024, The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Set underglow color based on battery level
+
+compatible: "zmk,behavior-underglow-battery"
+
+include: two_param.yaml
+
+properties:
+  threshold:
+    type: int

app/src/behaviors/behavior_underglow_battery.c

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2024 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_behavior_underglow_battery
+
+// Dependencies
+#include <zephyr/device.h>
+#include <drivers/behavior.h>
+#include <zephyr/logging/log.h>
+#include <zmk/battery.h>
+#include <zmk/event_manager.h>
+#include <zmk/events/battery_state_changed.h>
+#include <zmk/events/underglow_color_changed.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#if DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)
+
+struct underglow_battery_data {
+    uint32_t layers;
+};
+
+struct underglow_battery_config {
+    int threshold;
+};
+
+static struct underglow_battery_data underglow_battery_data = {.layers = 0};
+
+static int underglow_battery_init(const struct device *dev) { return 0; };
+
+static int underglow_battery_process(struct zmk_behavior_binding *binding,
+                                     struct zmk_behavior_binding_event event) {
+    const struct device *dev = zmk_behavior_get_binding(binding->behavior_dev);
+    const struct underglow_battery_config *config = dev->config;
+    struct underglow_battery_data *data = dev->data;
+    data->layers |= BIT(event.layer);
+    int bat = zmk_battery_state_of_charge();
+
+    if (bat >= config->threshold)
+        return binding->param2;
+    else
+        return binding->param1;
+}
+
+static const struct behavior_driver_api underglow_battery_driver_api = {
+    .binding_pressed = underglow_battery_process,
+    .locality = BEHAVIOR_LOCALITY_GLOBAL,
+#if IS_ENABLED(CONFIG_ZMK_BEHAVIOR_METADATA)
+    .get_parameter_metadata = zmk_behavior_get_empty_param_metadata,
+#endif // IS_ENABLED(CONFIG_ZMK_BEHAVIOR_METADATA)
+};
+
+static int underglow_battery_listener(const zmk_event_t *eh);
+
+ZMK_LISTENER(behavior_underglow_battery, underglow_battery_listener);
+ZMK_SUBSCRIPTION(behavior_underglow_battery, zmk_battery_state_changed);
+
+static int underglow_battery_listener(const zmk_event_t *eh) {
+    raise_zmk_underglow_color_changed((struct zmk_underglow_color_changed){
+        .layers = underglow_battery_data.layers, .wakeup = false});
+
+    return ZMK_EV_EVENT_BUBBLE;
+}
+
+#define KP_INST(n)                                                                                 \
+    static struct underglow_battery_config underglow_battery_config_##n = {                        \
+        .threshold = DT_INST_PROP(n, threshold)};                                                  \
+    BEHAVIOR_DT_INST_DEFINE(n, underglow_battery_init, NULL, &underglow_battery_data,              \
+                            &underglow_battery_config_##n, POST_KERNEL,                            \
+                            CONFIG_KERNEL_INIT_PRIORITY_DEFAULT, &underglow_battery_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(KP_INST)
+
+#endif /* DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT) */