feat: LED indicators displaying

app/CMakeLists.txt

@@ -80,6 +80,7 @@ target_sources_ifdef(CONFIG_USB app PRIVATE src/usb.c)
 target_sources_ifdef(CONFIG_ZMK_BLE app PRIVATE src/hog.c)
 target_sources_ifdef(CONFIG_ZMK_RGB_UNDERGLOW app PRIVATE src/rgb_underglow.c)
 target_sources_ifdef(CONFIG_ZMK_BACKLIGHT app PRIVATE src/backlight.c)
+target_sources_ifdef(CONFIG_ZMK_LED_INDICATORS app PRIVATE src/led_indicators.c)
 target_sources(app PRIVATE src/endpoints.c)
 target_sources(app PRIVATE src/hid_listener.c)
 target_sources(app PRIVATE src/led_indicators_generic.c)

app/Kconfig

@@ -358,6 +358,20 @@ config ZMK_BACKLIGHT_AUTO_OFF_USB
 #ZMK_BACKLIGHT
 endif
 
+menuconfig ZMK_LED_INDICATORS
+	bool "LED indicators"
+	select LED
+
+if ZMK_LED_INDICATORS
+
+config ZMK_LED_INDICATORS_BRT
+	int "Brightness in percent"
+	range 1 100
+	default 80
+
+#ZMK_LED_INDICATORS
+endif
+
 #Display/LED Options
 endmenu
 

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

@@ -0,0 +1,20 @@
+# Copyright (c) 2021 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: LED indicators
+
+compatible: "zmk,led-indicators"
+
+child-binding:
+  description: LED indicator
+
+  properties:
+    ctrl:
+      type: phandle
+      required: true
+    index:
+      type: int
+      required: true
+    binding:
+      type: int
+      required: true

app/src/led_indicators.c

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2022 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <kernel.h>
+#include <device.h>
+#include <init.h>
+
+#include <logging/log.h>
+#include <drivers/led.h>
+
+#include <zmk/event_manager.h>
+#include <zmk/led_indicators.h>
+#include <zmk/events/led_indicator_changed.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+BUILD_ASSERT(DT_HAS_CHOSEN(zmk_led_indicators),
+             "CONFIG_ZMK_LED_INDICATORS is enabled but no zmk,led-indicators chosen node found");
+
+struct zmk_led_cfg {
+    const struct device *ctrl;
+    int index;
+    int binding;
+};
+
+#define LED_CFG(node_id)                                                                           \
+    (struct zmk_led_cfg){                                                                          \
+        .ctrl = DEVICE_DT_GET(DT_PHANDLE(node_id, ctrl)),                                          \
+        .index = DT_PROP(node_id, index),                                                          \
+        .binding = DT_PROP(node_id, binding),                                                      \
+    },
+
+static const struct zmk_led_cfg led_indicators[] = {
+    DT_FOREACH_CHILD(DT_CHOSEN(zmk_led_indicators), LED_CFG)};
+
+static int leds_init(const struct device *_arg) {
+    for (int i = 0; i < ARRAY_SIZE(led_indicators); i++) {
+        if (!device_is_ready(led_indicators[i].ctrl)) {
+            LOG_ERR("LED device \"%s\" is not ready", led_indicators[i].ctrl->name);
+            return -ENODEV;
+        }
+    }
+
+    return 0;
+}
+
+static int leds_listener(const zmk_event_t *eh) {
+    zmk_leds_flags_t flags = zmk_leds_get_current_flags();
+
+    for (int i = 0; i < ARRAY_SIZE(led_indicators); i++) {
+        uint8_t value =
+            (flags & BIT(led_indicators[i].binding)) ? CONFIG_ZMK_LED_INDICATORS_BRT : 0;
+        int rc = led_set_brightness(led_indicators[i].ctrl, led_indicators[i].index, value);
+        if (rc != 0) {
+            return rc;
+        }
+    }
+
+    return 0;
+}
+
+ZMK_LISTENER(leds_listener, leds_listener);
+ZMK_SUBSCRIPTION(leds_listener, zmk_led_changed);
+
+SYS_INIT(leds_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);