docs: add led indicators documentation

zmkfirmware · Oct 23, 2021 · 4b320f5 · 4b320f5
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diff --git a/docs/docs/development/hardware-metadata-files.md b/docs/docs/development/hardware-metadata-files.md
@@ -94,6 +94,7 @@ Boards and shields should document the sets of hardware features found on them u
 - `display` - Indicates the hardware includes a display for use with the ZMK display functionality.
 - `encoder` - Indicates the hardware contains one or more rotary encoders.
 - `underglow` - Indicates the hardware includes underglow LEDs.
+- `led_indicators` - Indicates the hardware includes LED indicators.
 - `pointer` (future) - Used to indicate the hardware includes one or more pointer inputs, e.g. joystick, touchpad, or trackpoint.
 
 ### Siblings

diff --git a/docs/docs/features/led-indicators.md b/docs/docs/features/led-indicators.md
@@ -0,0 +1,184 @@
+---
+title: LED indicators
+sidebar_label: LED indicators
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+ZMK supports the following LED indicators:
+
+- Num Lock
+- Caps Lock
+- Scroll Lock
+- Compose
+- Kana
+
+## Enabling LED indicators
+
+To enable LED indicators on your board or shield, simply enable the `CONFIG_ZMK_LED_INDICATORS` configuration values in the `.conf` file of your user config directory as such:
+
+```
+CONFIG_ZMK_LED_INDICATORS=y
+```
+
+You can also configure the brightness of the LEDs using:
+
+```
+CONFIG_ZMK_LED_INDICATORS_BRT=80
+```
+
+If your board or shield does not have LED indicators configured, refer to [Adding LED indicators to a Board](#adding-led-indicators-to-a-board).
+
+## Adding LED indicators to a board
+
+You can use any LED driver supported by ZMK or Zephyr, it is recommended to use the `ZMK_LED_PWM` driver.
+
+<Tabs
+defaultValue="pwm"
+values={[
+{label: 'ZMK_LED_PWM driver', value: 'pwm'},
+{label: 'Other drivers', value: 'other'},
+]}>
+<TabItem value="pwm">
+
+First you have to enable the driver by adding the following line to your `.conf` file:
+
+```
+CONFIG_ZMK_LED_PWM=y
+```
+
+Next, you need to enable PWM by adding the following lines to your `.overlay` file:
+
+```
+&pwm0 {
+	status = "okay";
+	ch0-pin = <33>;
+	/* ch0-inverted; */
+	ch1-pin = <35>;
+	/* ch1-inverted; */
+};
+```
+
+You have to declere a channel for each LED. A single PWM module has a fixed number of channels depending on your SoC, if you have many LEDs you may want to use `&pwm1` or ` &pwm2` as well.
+
+The value `chX-pin` represents the pin that controls the LEDs. To calculate the value to use, you need a bit of math. You need the hardware port and run it through a function.
+**32 \* X + Y** = `<Pin number>` where X is first part of the hardware port "PX.01" and Y is the second part of the hardware port "P1.Y".
+
+For example, _P1.13_ would give you _32 \* 1 + 13_ = `<45>` and _P0.15_ would give you _32 \* 0 + 15_ = `<15>`.
+
+If you need to invert the signal, you may want to enable `chX-inverted`.
+
+Then you have to add the following lines to your `.dtsi` file inside the root devicetree node:
+
+```
+pwmleds: pwmleds {
+    compatible = "pwm-leds";
+    label = "LED indicators";
+    pwm_led_0 {
+        pwms = <&pwm0 33>;
+        label = "Caps lock LED";
+    };
+    pwm_led_1 {
+        pwms = <&pwm0 35>;
+        label = "Num lock LED";
+    };
+};
+```
+
+The value inside `pwm_led_X` must be the same as you used before.
+
+Then you have to add the following lines to your `.dtsi` file inside the root devicetree node:
+
+```
+led_indicators: led_indicators {
+    compatible = "zmk,led-indicators";
+    caps_lock_led {
+        dev = <&pwmleds>;
+        index = <0>;
+        binding = <LED_CAPSLOCK>;
+    };
+    num_lock_led {
+        dev = <&pwmleds>;
+        index = <1>;
+        binding = <LED_NUMLOCK>;
+    };
+};
+```
+
+You can find the definition of LEDs here: [`dt-bindings/zmk/led_indicators.h`](https://github.com/zmkfirmware/zmk/tree/main/app/include/dt-bindings/zmk/led_indicators.h).
+
+
+Finally you need to add `led_indicators` to the `chosen` element of the root devicetree node:
+
+```
+chosen {
+    ...
+    zmk,led_indicators = &led_indicators;
+};
+```
+
+</TabItem>
+<TabItem value="other">
+
+First, you need to enable your LED driver:
+
+```
+&my_led_driver: my_led_driver {
+    ...
+};
+```
+
+Then you have to add the following lines to your `.dtsi` file inside the root devicetree node:
+
+```
+led_indicators: led_indicators {
+    compatible = "zmk,led-indicators";
+    caps_lock_led {
+        dev = <&my_led_driver>;
+        index = <0>;
+        binding = <LED_CAPSLOCK>;
+    };
+    num_lock_led {
+        dev = <&my_led_driver>;
+        index = <1>;
+        binding = <LED_NUMLOCK>;
+    };
+};
+```
+
+You can find the definition of LEDs here: [`dt-bindings/zmk/led_indicators.h`](https://github.com/zmkfirmware/zmk/tree/main/app/include/dt-bindings/zmk/led_indicators.h).
+
+Finally you need to add `led_indicators` to the `chosen` element of the root devicetree node:
+
+```
+chosen {
+    ...
+    zmk,led_indicators = &led_indicators;
+};
+```
+
+</TabItem>
+</Tabs>
+
+## Custom behavior
+
+To implement custom behavior, such as a display widget, you must first **remove** `CONFIG_ZMK_LED_INDICATORS=y` from your `.conf` file. Then you can write a listener to implement the behavior you want, for example:
+
+```C
+#include <dt-bindings/zmk/led_indicators.h>
+
+static int led_indicators_listener(const zmk_event_t *eh) {
+    const struct zmk_keycode_state_changed *ev = as_zmk_led_indicator_changed(eh);
+    zmk_led_indicators_flags_t leds = ev->leds;
+
+    if (leds & BIT(LED_CAPSLOCK)) {
+        // do something
+    }
+
+    return 0;
+}
+
+ZMK_LISTENER(led_indicators_listener, led_indicators_listener);
+ZMK_SUBSCRIPTION(led_indicators_listener, zmk_led_indicator_changed);
+```
diff --git a/docs/docs/hardware.mdx b/docs/docs/hardware.mdx
@@ -18,6 +18,7 @@ In addition to the basic keyboard functionality, there is some initial support f
 - Encoders
 - Displays
 - RGB Underglow
+- LED indicators
 
 Until detailed documentation is available, feel free to ask questions about how these are supported in the [Discord server](https://zmk.dev/community/discord/invite).
 

diff --git a/docs/docs/intro.md b/docs/docs/intro.md
@@ -28,6 +28,7 @@ ZMK is currently missing some features found in other popular firmware. This tab
 | [Encoders](features/encoders.md)[^1]                                                                                               | ✅  |    ✅     | ✅  |
 | [Display Support](features/displays.md)[^2]                                                                                        | 🚧  |    🚧     | ✅  |
 | [RGB Underglow](features/underglow.md)                                                                                             | ✅  |    ✅     | ✅  |
+| [LED indicators](features/led-indicators.md)                                                                                       | ✅  |           | ✅  |
 | One Shot Keys                                                                                                                      | ✅  |    ✅     | ✅  |
 | [Combo Keys](features/combos.md)                                                                                                   | ✅  |           | ✅  |
 | Macros                                                                                                                             | 🚧  |    ✅     | ✅  |

diff --git a/docs/sidebars.js b/docs/sidebars.js
@@ -14,6 +14,7 @@ module.exports = {
       "features/displays",
       "features/encoders",
       "features/underglow",
+      "features/led-indicators",
       "features/beta-testing",
     ],
     Behaviors: [