RGB underglow status support

Adds Glove80's status indicator using RGB underglow support. Requires ZMK
PR#999 and PR#1243.

The underglow status is able to show layer state, battery levels,
caps/num/scroll-lock, BLE and USB state. The underglow positions selected for
each of these indicators is configured using the new devicetree node
zmk,underglow-indicators, which takes an array of integer LED positions for each
feature.

app/dts/bindings/zmk,underglow-indicators.yaml

@@ -0,0 +1,35 @@
+# Copyright (c) 2020, The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Underglow indicators
+
+compatible: "zmk,underglow-indicators"
+
+properties:
+  bat-lhs:
+    type: array
+    required: true
+  bat-rhs:
+    type: array
+    required: true
+  capslock:
+    type: int
+    required: true
+  numlock:
+    type: int
+    required: true
+  scrolllock:
+    type: int
+    required: true
+  layer-state:
+    type: array
+    required: true
+  ble-state:
+    type: array
+    required: true
+  usb-state:
+    type: int
+    required: true
+  output-fallback:
+    type: int
+    required: true

app/include/dt-bindings/zmk/rgb.h

@@ -19,6 +19,7 @@
 #define RGB_EFR_CMD 12
 #define RGB_EFS_CMD 13
 #define RGB_COLOR_HSB_CMD 14
+#define RGB_STATUS_CMD 15
 
 #define RGB_TOG RGB_TOG_CMD 0
 #define RGB_ON RGB_ON_CMD 0
@@ -33,6 +34,7 @@
 #define RGB_SPD RGB_SPD_CMD 0
 #define RGB_EFF RGB_EFF_CMD 0
 #define RGB_EFR RGB_EFR_CMD 0
+#define RGB_STATUS RGB_STATUS_CMD 0
 #define RGB_COLOR_HSB_VAL(h, s, v) (((h) << 16) + ((s) << 8) + (v))
 #define RGB_COLOR_HSB(h, s, v) RGB_COLOR_HSB_CMD##(RGB_COLOR_HSB_VAL(h, s, v))
 #define RGB_COLOR_HSV RGB_COLOR_HSB

app/include/zmk/ble.h

@@ -33,6 +33,7 @@ bt_addr_le_t *zmk_ble_active_profile_addr(void);
 bool zmk_ble_active_profile_is_open(void);
 bool zmk_ble_active_profile_is_connected(void);
 char *zmk_ble_active_profile_name(void);
+int8_t zmk_ble_profile_status(uint8_t index);
 
 int zmk_ble_unpair_all(void);
 

app/include/zmk/endpoints.h

@@ -68,6 +68,8 @@ int zmk_endpoints_toggle_transport(void);
  */
 struct zmk_endpoint_instance zmk_endpoints_selected(void);
 
+bool zmk_endpoints_preferred_transport_is_active();
+
 int zmk_endpoints_send_report(uint16_t usage_page);
 
 #if IS_ENABLED(CONFIG_ZMK_MOUSE)

app/include/zmk/rgb_underglow.h

@@ -27,3 +27,4 @@ int zmk_rgb_underglow_change_sat(int direction);
 int zmk_rgb_underglow_change_brt(int direction);
 int zmk_rgb_underglow_change_spd(int direction);
 int zmk_rgb_underglow_set_hsb(struct zmk_led_hsb color);
+int zmk_rgb_underglow_status(void);

app/src/behaviors/behavior_rgb_underglow.c

@@ -131,6 +131,8 @@ static int on_keymap_binding_pressed(struct zmk_behavior_binding *binding,
         return zmk_rgb_underglow_set_hsb((struct zmk_led_hsb){.h = (binding->param2 >> 16) & 0xFFFF,
                                                               .s = (binding->param2 >> 8) & 0xFF,
                                                               .b = binding->param2 & 0xFF});
+    case RGB_STATUS_CMD:
+        return zmk_rgb_underglow_status();
     }
 
     return -ENOTSUP;

app/src/ble.c

@@ -129,6 +129,23 @@ bool zmk_ble_active_profile_is_connected(void) {
     return info.state == BT_CONN_STATE_CONNECTED;
 }
 
+int8_t zmk_ble_profile_status(uint8_t index) {
+    if (index >= ZMK_BLE_PROFILE_COUNT)
+        return -1;
+    bt_addr_le_t *addr = &profiles[index].peer;
+    struct bt_conn *conn;
+    int result;
+    if (!bt_addr_le_cmp(addr, BT_ADDR_LE_ANY)) {
+        result = 0; // disconnected
+    } else if ((conn = bt_conn_lookup_addr_le(BT_ID_DEFAULT, addr)) == NULL) {
+        result = 1; // paired
+    } else {
+        result = 2; // connected
+        bt_conn_unref(conn);
+    }
+    return result;
+}
+
 #define CHECKED_ADV_STOP()                                                                         \
     err = bt_le_adv_stop();                                                                        \
     advertising_status = ZMK_ADV_NONE;                                                             \

app/src/endpoints.c

@@ -302,6 +302,10 @@ static struct zmk_endpoint_instance get_selected_instance(void) {
     return instance;
 }
 
+bool zmk_endpoints_preferred_transport_is_active(void) {
+    return preferred_transport == get_selected_transport();
+}
+
 static int zmk_endpoints_init(void) {
 #if IS_ENABLED(CONFIG_SETTINGS)
     settings_subsys_init();