Feature backlight

app/CMakeLists.txt

@@ -63,6 +63,7 @@ if ((NOT CONFIG_ZMK_SPLIT) OR CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL)
  target_sources(app PRIVATE src/keymap.c)
 endif()
 target_sources_ifdef(CONFIG_ZMK_RGB_UNDERGLOW app PRIVATE src/behaviors/behavior_rgb_underglow.c)
+target_sources_ifdef(CONFIG_ZMK_BACKLIGHT app PRIVATE src/behaviors/behavior_backlight.c)
 target_sources_ifdef(CONFIG_ZMK_BLE app PRIVATE src/behaviors/behavior_bt.c)
 target_sources_ifdef(CONFIG_ZMK_BLE app PRIVATE src/ble.c)
 target_sources_ifdef(CONFIG_ZMK_BLE app PRIVATE src/battery.c)
@@ -76,6 +77,7 @@ endif()
 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(app PRIVATE src/endpoints.c)
 target_sources(app PRIVATE src/hid_listener.c)
 target_sources(app PRIVATE src/main.c)

app/Kconfig

@@ -249,7 +249,7 @@ menu "Display/LED Options"
 
 rsource "src/display/Kconfig"
 
-config ZMK_RGB_UNDERGLOW
+menuconfig ZMK_RGB_UNDERGLOW
  bool "RGB Adressable LED Underglow"
  select LED_STRIP
 
@@ -320,6 +320,35 @@ config ZMK_RGB_UNDERGLOW_ON_START
 #ZMK_RGB_UNDERGLOW
 endif
 
+menuconfig ZMK_BACKLIGHT
+ bool "LED backlight"
+ select LED
+
+if ZMK_BACKLIGHT
+
+config ZMK_BACKLIGHT_BRT_STEP
+ int "Brightness step in percent"
+ range 1 100
+ default 20
+
+config ZMK_BACKLIGHT_BRT_START
+ int "Default brightness in percent"
+ range 1 100
+ default 40
+
+config ZMK_BACKLIGHT_ON_START
+ bool "Default backlight state"
+ default y
+
+config ZMK_BACKLIGHT_AUTO_OFF_IDLE
+ bool "Turn off backlight when keyboard goes into idle state"
+
+config ZMK_BACKLIGHT_AUTO_OFF_USB
+ bool "Turn off backlight when USB is disconnected"
+
+#ZMK_BACKLIGHT
+endif
+
 #Display/LED Options
 endmenu
 
@@ -370,7 +399,7 @@ config ZMK_COMBO_MAX_KEYS_PER_COMBO
  int "Maximum number of keys per combo"
  default 4
 
-#Display/LED Options
+#Combo options
 endmenu
 
 menu "Advanced"

app/dts/behaviors.dtsi

@@ -16,3 +16,4 @@
 #include <behaviors/outputs.dtsi>
 #include <behaviors/caps_word.dtsi>
 #include <behaviors/key_repeat.dtsi>
+#include <behaviors/backlight.dtsi>

app/dts/behaviors/backlight.dtsi

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2021 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+ / {
+ behaviors {
+ /omit-if-no-ref/ bl: behavior_backlight {
+ compatible = "zmk,behavior-backlight";
+ label = "BCKLGHT";
+ #binding-cells = <2>;
+ };
+ };
+};

app/dts/bindings/behaviors/zmk,behavior-backlight.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2021 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Backlight behavior
+
+compatible: "zmk,behavior-backlight"
+
+include: two_param.yaml

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

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2021 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define BL_ON_CMD 0
+#define BL_OFF_CMD 1
+#define BL_TOG_CMD 2
+#define BL_INC_CMD 3
+#define BL_DEC_CMD 4
+#define BL_CYCLE_CMD 5
+#define BL_SET_CMD 6
+
+#define BL_ON BL_ON_CMD 0
+#define BL_OFF BL_OFF_CMD 0
+#define BL_TOG BL_TOG_CMD 0
+#define BL_INC BL_INC_CMD 0
+#define BL_DEC BL_DEC_CMD 0
+#define BL_CYCLE BL_CYCLE_CMD 0
+#define BL_SET BL_SET_CMD

app/include/zmk/backlight.h

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2021 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+int zmk_backlight_on();
+int zmk_backlight_off();
+int zmk_backlight_toggle();
+bool zmk_backlight_is_on();
+
+int zmk_backlight_set_brt(uint8_t brightness);
+uint8_t zmk_backlight_get_brt();
+uint8_t zmk_backlight_calc_brt(int direction);
+uint8_t zmk_backlight_calc_brt_cycle();

app/src/backlight.c

@@ -0,0 +1,189 @@
+/*
+ * Copyright (c) 2021 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <device.h>
+#include <devicetree.h>
+#include <init.h>
+#include <kernel.h>
+
+#include <drivers/led.h>
+#include <logging/log.h>
+#include <settings/settings.h>
+
+#include <zmk/activity.h>
+#include <zmk/backlight.h>
+#include <zmk/usb.h>
+#include <zmk/event_manager.h>
+#include <zmk/events/activity_state_changed.h>
+#include <zmk/events/usb_conn_state_changed.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+BUILD_ASSERT(DT_HAS_CHOSEN(zmk_backlight),
+ "CONFIG_ZMK_BACKLIGHT is enabled but no zmk,backlight chosen node found");
+
+static const struct device *const backlight_dev = DEVICE_DT_GET(DT_CHOSEN(zmk_backlight));
+
+#define CHILD_COUNT(...) +1
+#define DT_NUM_CHILD(node_id) (DT_FOREACH_CHILD(node_id, CHILD_COUNT))
+
+#define BACKLIGHT_NUM_LEDS (DT_NUM_CHILD(DT_CHOSEN(zmk_backlight)))
+
+#define BRT_MAX 100
+
+struct backlight_state {
+ uint8_t brightness;
+ bool on;
+};
+
+static struct backlight_state state = {.brightness = CONFIG_ZMK_BACKLIGHT_BRT_START,
+ .on = IS_ENABLED(CONFIG_ZMK_BACKLIGHT_ON_START)};
+
+static int zmk_backlight_update() {
+ uint8_t brt = zmk_backlight_get_brt();
+ LOG_DBG("Update backlight brightness: %d%%", brt);
+
+ for (int i = 0; i < BACKLIGHT_NUM_LEDS; i++) {
+ int rc = led_set_brightness(backlight_dev, i, brt);
+ if (rc != 0) {
+ LOG_ERR("Failed to update backlight LED %d: %d", i, rc);
+ return rc;
+ }
+ }
+ return 0;
+}
+
+#if IS_ENABLED(CONFIG_SETTINGS)
+static int backlight_settings_load_cb(const char *name, size_t len, settings_read_cb read_cb,
+ void *cb_arg, void *param) {
+ const char *next;
+ if (settings_name_steq(name, "state", &next) && !next) {
+ if (len != sizeof(state)) {
+ return -EINVAL;
+ }
+
+ int rc = read_cb(cb_arg, &state, sizeof(state));
+ return MIN(rc, 0);
+ }
+ return -ENOENT;
+}
+
+static void backlight_save_work_handler(struct k_work *work) {
+ settings_save_one("backlight/state", &state, sizeof(state));
+}
+
+static K_DELAYED_WORK_DEFINE(backlight_save_work, backlight_save_work_handler);
+#endif
+
+static int zmk_backlight_init(const struct device *_arg) {
+ if (!device_is_ready(backlight_dev)) {
+ LOG_ERR("Backlight device \"%s\" is not ready", backlight_dev->name);
+ return -ENODEV;
+ }
+
+#if IS_ENABLED(CONFIG_SETTINGS)
+ settings_subsys_init();
+ int rc = settings_load_subtree_direct("backlight", backlight_settings_load_cb, NULL);
+ if (rc != 0) {
+ LOG_ERR("Failed to load backlight settings: %d", rc);
+ }
+#endif
+
+ return zmk_backlight_update();
+}
+
+static int zmk_backlight_update_and_save() {
+ int rc = zmk_backlight_update();
+ if (rc != 0) {
+ return rc;
+ }
+
+#if IS_ENABLED(CONFIG_SETTINGS)
+ k_delayed_work_cancel(&backlight_save_work);
+ return k_delayed_work_submit(&backlight_save_work, K_MSEC(CONFIG_ZMK_SETTINGS_SAVE_DEBOUNCE));
+#else
+ return 0;
+#endif
+}
+
+int zmk_backlight_on() {
+ state.brightness = MAX(state.brightness, CONFIG_ZMK_BACKLIGHT_BRT_STEP);
+ state.on = true;
+ return zmk_backlight_update_and_save();
+}
+
+int zmk_backlight_off() {
+ state.on = false;
+ return zmk_backlight_update_and_save();
+}
+
+int zmk_backlight_toggle() { return state.on ? zmk_backlight_off() : zmk_backlight_on(); }
+
+bool zmk_backlight_is_on() { return state.on; }
+
+int zmk_backlight_set_brt(uint8_t brightness) {
+ state.brightness = MIN(brightness, BRT_MAX);
+ state.on = (state.brightness > 0);
+ return zmk_backlight_update_and_save();
+}
+
+uint8_t zmk_backlight_get_brt() { return state.on ? state.brightness : 0; }
+
+uint8_t zmk_backlight_calc_brt(int direction) {
+ int brt = state.brightness + (direction * CONFIG_ZMK_BACKLIGHT_BRT_STEP);
+ return CLAMP(brt, 0, BRT_MAX);
+}
+
+uint8_t zmk_backlight_calc_brt_cycle() {
+ if (state.brightness == BRT_MAX) {
+ return 0;
+ } else {
+ return zmk_backlight_calc_brt(1);
+ }
+}
+
+#if IS_ENABLED(CONFIG_ZMK_BACKLIGHT_AUTO_OFF_IDLE) || IS_ENABLED(CONFIG_ZMK_BACKLIGHT_AUTO_OFF_USB)
+static int backlight_auto_state(bool *prev_state, bool new_state) {
+ if (state.on == new_state) {
+ return 0;
+ }
+ state.on = new_state && *prev_state;
+ *prev_state = !new_state;
+ return zmk_backlight_update();
+}
+
+static int backlight_event_listener(const zmk_event_t *eh) {
+
+#if IS_ENABLED(CONFIG_ZMK_BACKLIGHT_AUTO_OFF_IDLE)
+ if (as_zmk_activity_state_changed(eh)) {
+ static bool prev_state = false;
+ return backlight_auto_state(&prev_state, zmk_activity_get_state() == ZMK_ACTIVITY_ACTIVE);
+ }
+#endif
+
+#if IS_ENABLED(CONFIG_ZMK_BACKLIGHT_AUTO_OFF_USB)
+ if (as_zmk_usb_conn_state_changed(eh)) {
+ static bool prev_state = false;
+ return backlight_auto_state(&prev_state, zmk_usb_is_powered());
+ }
+#endif
+
+ return -ENOTSUP;
+}
+
+ZMK_LISTENER(backlight, backlight_event_listener);
+#endif // IS_ENABLED(CONFIG_ZMK_BACKLIGHT_AUTO_OFF_IDLE) ||
+ // IS_ENABLED(CONFIG_ZMK_BACKLIGHT_AUTO_OFF_USB)
+
+#if IS_ENABLED(CONFIG_ZMK_BACKLIGHT_AUTO_OFF_IDLE)
+ZMK_SUBSCRIPTION(backlight, zmk_activity_state_changed);
+#endif
+
+#if IS_ENABLED(CONFIG_ZMK_BACKLIGHT_AUTO_OFF_USB)
+ZMK_SUBSCRIPTION(backlight, zmk_usb_conn_state_changed);
+#endif
+
+SYS_INIT(zmk_backlight_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);