refactor(behaviors): Convert state dependent params.

* Allow each behavior to map a relative binding, e.g. "toggle",
  to an absolute one, e.g. "on", before being invoked.

app/include/drivers/behavior.h

@@ -27,6 +27,7 @@ typedef int (*behavior_sensor_keymap_binding_callback_t)(struct zmk_behavior_bin
                                                          int64_t timestamp);
 
 __subsystem struct behavior_driver_api {
+    behavior_keymap_binding_callback_t binding_convert_central_state_dependent_params;
     behavior_keymap_binding_callback_t binding_pressed;
     behavior_keymap_binding_callback_t binding_released;
     behavior_sensor_keymap_binding_callback_t sensor_binding_triggered;
@@ -35,6 +36,30 @@ __subsystem struct behavior_driver_api {
  * @endcond
  */
 
+/**
+ * @brief Handle the keymap binding which needs to be converted from relative "toggle" to absolute
+ * "turn on"
+ * @param binding Pointer to the details so of the binding
+ * @param event The event that triggered use of the binding
+ *
+ * @retval 0 If successful.
+ * @retval Negative errno code if failure.
+ */
+__syscall int behavior_keymap_binding_convert_central_state_dependent_params(
+    struct zmk_behavior_binding *binding, struct zmk_behavior_binding_event event);
+
+static inline int z_impl_behavior_keymap_binding_convert_central_state_dependent_params(
+    struct zmk_behavior_binding *binding, struct zmk_behavior_binding_event event) {
+    const struct device *dev = device_get_binding(binding->behavior_dev);
+    const struct behavior_driver_api *api = (const struct behavior_driver_api *)dev->api;
+
+    if (api->binding_convert_central_state_dependent_params == NULL) {
+        return 0;
+    }
+
+    return api->binding_convert_central_state_dependent_params(binding, event);
+}
+
 /**
  * @brief Handle the keymap binding being pressed
  * @param dev Pointer to the device structure for the driver instance.

app/src/behaviors/behavior_ext_power.c

@@ -18,6 +18,22 @@ LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
 #if DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)
 
+static int
+on_keymap_binding_convert_central_state_dependent_params(struct zmk_behavior_binding *binding,
+                                                         struct zmk_behavior_binding_event event) {
+    const struct device *ext_power = device_get_binding("EXT_POWER");
+    if (ext_power == NULL) {
+        LOG_ERR("Unable to retrieve ext_power device: %d", binding->param1);
+        return -EIO;
+    }
+
+    if (binding->param1 == EXT_POWER_TOGGLE_CMD) {
+        binding->param1 = ext_power_get(ext_power) > 0 ? EXT_POWER_OFF_CMD : EXT_POWER_ON_CMD;
+    }
+
+    return 0;
+}
+
 static int on_keymap_binding_pressed(struct zmk_behavior_binding *binding,
                                      struct zmk_behavior_binding_event event) {
     const struct device *ext_power = device_get_binding("EXT_POWER");
@@ -51,6 +67,8 @@ static int on_keymap_binding_released(struct zmk_behavior_binding *binding,
 static int behavior_ext_power_init(const struct device *dev) { return 0; };
 
 static const struct behavior_driver_api behavior_ext_power_driver_api = {
+    .binding_convert_central_state_dependent_params =
+        on_keymap_binding_convert_central_state_dependent_params,
     .binding_pressed = on_keymap_binding_pressed,
     .binding_released = on_keymap_binding_released,
 };

app/src/behaviors/behavior_rgb_underglow.c

@@ -20,6 +20,27 @@ LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
 static int behavior_rgb_underglow_init(const struct device *dev) { return 0; }
 
+static int
+on_keymap_binding_convert_central_state_dependent_params(struct zmk_behavior_binding *binding,
+                                                         struct zmk_behavior_binding_event event) {
+    switch (binding->param1) {
+    case RGB_TOG_CMD: {
+        bool state;
+        int err = zmk_rgb_underglow_get_state(&state);
+        if (err) {
+            LOG_ERR("Failed to get RGB underglow state (err %d)", err);
+            return err;
+        }
+
+        binding->param1 = state ? RGB_OFF_CMD : RGB_ON_CMD;
+        LOG_DBG("RGB relative toggle convert to absolute %s", state ? "OFF" : "ON");
+        return 0;
+    }
+    default:
+        return 0;
+    }
+};
+
 static int on_keymap_binding_pressed(struct zmk_behavior_binding *binding,
                                      struct zmk_behavior_binding_event event) {
     switch (binding->param1) {
@@ -63,6 +84,8 @@ static int on_keymap_binding_released(struct zmk_behavior_binding *binding,
 }
 
 static const struct behavior_driver_api behavior_rgb_underglow_driver_api = {
+    .binding_convert_central_state_dependent_params =
+        on_keymap_binding_convert_central_state_dependent_params,
     .binding_pressed = on_keymap_binding_pressed,
     .binding_released = on_keymap_binding_released,
 };

app/src/keymap.c

@@ -153,7 +153,9 @@ const char *zmk_keymap_layer_label(uint8_t layer) {
 }
 
 int zmk_keymap_apply_position_state(int layer, uint32_t position, bool pressed, int64_t timestamp) {
-    struct zmk_behavior_binding *binding = &zmk_keymap[layer][position];
+    // We want to make a copy of this, since it may be converted from
+    // relative to absolute before being invoked
+    struct zmk_behavior_binding binding = zmk_keymap[layer][position];
     const struct device *behavior;
     struct zmk_behavior_binding_event event = {
         .layer = layer,
@@ -162,19 +164,25 @@ int zmk_keymap_apply_position_state(int layer, uint32_t position, bool pressed,
     };
 
     LOG_DBG("layer: %d position: %d, binding name: %s", layer, position,
-            log_strdup(binding->behavior_dev));
+            log_strdup(binding.behavior_dev));
 
-    behavior = device_get_binding(binding->behavior_dev);
+    behavior = device_get_binding(binding.behavior_dev);
 
     if (!behavior) {
         LOG_DBG("No behavior assigned to %d on layer %d", position, layer);
         return 1;
     }
 
+    int err = behavior_keymap_binding_convert_central_state_dependent_params(&binding, event);
+    if (err) {
+        LOG_ERR("Failed to convert relative to absolute behavior binding (err %d)", err);
+        return err;
+    }
+
     if (pressed) {
-        return behavior_keymap_binding_pressed(binding, event);
+        return behavior_keymap_binding_pressed(&binding, event);
     } else {
-        return behavior_keymap_binding_released(binding, event);
+        return behavior_keymap_binding_released(&binding, event);
     }
 }