Update WS2812 docs and add APA102 docs (#22106)

Co-authored-by: Nick Brassel <nick@tzarc.org>

docs/_summary.md

@@ -148,6 +148,7 @@
     * [Compatible Microcontrollers](compatible_microcontrollers.md)
     * [Drivers](hardware_drivers.md)
       * [ADC Driver](adc_driver.md)
+      * [APA102 Driver](apa102_driver.md)
       * [Audio Driver](audio_driver.md)
       * [I2C Driver](i2c_driver.md)
       * [SPI Driver](spi_driver.md)

docs/apa102_driver.md

@@ -0,0 +1,49 @@
+# APA102 Driver :id=apa102-driver
+
+This driver provides support for APA102 addressable RGB LEDs. They are similar to the [WS2812](ws2812_driver.md) LEDs, but have increased data and refresh rates.
+
+## Usage :id=usage
+
+In most cases, the APA102 driver code is automatically included if you are using either the [RGBLight](feature_rgblight.md) or [RGB Matrix](feature_rgb_matrix.md) feature with the `apa102` driver set, and you would use those APIs instead.
+
+However, if you need to use the driver standalone, add the following to your `rules.mk`:
+
+```make
+APA102_DRIVER_REQUIRED = yes
+```
+
+You can then call the APA102 API by including `apa102.h` in your code.
+
+## Basic Configuration :id=basic-configuration
+
+Add the following to your `config.h`:
+
+|Define                     |Default      |Description                                                       |
+|---------------------------|-------------|------------------------------------------------------------------|
+|`APA102_DI_PIN`            |*Not defined*|The GPIO pin connected to the DI pin of the first LED in the chain|
+|`APA102_CI_PIN`            |*Not defined*|The GPIO pin connected to the CI pin of the first LED in the chain|
+|`APA102_DEFAULT_BRIGHTNESS`|`31`         |The default global brightness level of the LEDs, from 0 to 31     |
+
+## API :id=api
+
+### `void apa102_setleds(rgb_led_t *start_led, uint16_t num_leds)`
+
+Send RGB data to the APA102 LED chain.
+
+#### Arguments :id=api-apa102-setleds-arguments
+
+ - `rgb_led_t *start_led`  
+   A pointer to the LED array.
+ - `uint16_t num_leds`  
+   The length of the LED array.
+
+---
+
+### `void apa102_set_brightness(uint8_t brightness)`
+
+Set the global brightness.
+
+#### Arguments :id=api-apa102-set-brightness-arguments
+
+ - `uint8_t brightness`  
+   The brightness level to set, from 0 to 31.

docs/reference_info_json.md

@@ -88,7 +88,7 @@ You can create `info.json` files at every level under `qmk_firmware/keyboards/<k
 
 ## APA102 :id=apa102
 
-Configures the APA102 driver.
+Configures the [APA102](apa102_driver.md) driver.
 
 * `apa102`
     * `clock_pin` (Required)