Add documentation for new Tuya dimmer component (#353)

* Add documentation for new Tuya dimmer component

* add more info and change configuration names

* Rename file to match platform name

* Move default gamma_correct/transition_length handling to code


Co-authored-by: Samuel Sieb <samuel@sieb.net>
Co-authored-by: Otto Winter <otto@otto-winter.com>

components/light/tuya.rst

@@ -0,0 +1,96 @@
+Tuya Dimmer
+===========
+
+.. seo::
+    :description: Instructions for setting up a Tuya dimmer switch.
+    :image: brightness-medium.png
+
+The ``tuya`` light platform creates a simple brightness-only light from a
+tuya serial component.
+
+.. warning::
+
+    Some of these dimmers have no way of serial flashing without destroying them.
+    Make sure you have some way to OTA upload configured before flashing.  This means you need
+    to have working wifi, ota, and maybe api sections in the config.
+    The dimmer switch I got would hang if the logger was configured to use the serial port
+    which meant it was bricked until I cut it open.
+
+There are two components, the Tuya bus and the dimmer that uses it.  The ``tuya``
+component requires a :ref:`UART bus <uart>` to be configured.  Put the ``tuya`` component in
+the config and it will list the possible devices for you in the config log.
+
+.. code-block:: yaml
+
+    # Example configuration entry
+    # Make sure your wifi will connect
+    wifi:
+      ssid: "ssid"
+      password: "password"
+
+    # Make sure logging is not using the serial port
+    logger:
+      baud_rate: 0
+
+    # Enable Home Assistant API
+    api:
+
+    # Make sure you can upload new firmware OTA
+    ota:
+
+    # My dimmer used the hardware serial port on the alternate pins
+    uart:
+      rx_pin: GPIO13
+      tx_pin: GPIO15
+      baud_rate: 9600
+
+    # Register the Tuya MCU connection
+    tuya:
+
+Here is an example output for a Tuya dimmer:
+
+.. code-block:: text
+
+    [21:50:28][C][tuya:024]: Tuya:
+    [21:50:28][C][tuya:031]:   Datapoint 3: int value (value: 139)
+    [21:50:28][C][tuya:029]:   Datapoint 1: switch (value: OFF)
+
+On this dimmer, the toggle switch is datapoint 1 and the dimmer value is datapoint 3.
+Now you can create the light.
+
+.. code-block:: yaml
+
+    # Create a light using the dimmer
+    light:
+      - platform: "tuya"
+        name: "dim1"
+        dimmer_datapoint: 3
+        switch_datapoint: 1
+
+Configuration variables:
+------------------------
+
+- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.
+- **name** (**Required**, string): The name of the light.
+- **dimmer_datapoint** (**Required**, int): The datapoint id number of the dimmer value.
+- **switch_datapoint** (*Optional*, int): The datapoint id number of the power switch.  My dimmer
+  required this to be able to turn the light on and off.  Without this you would only be able to
+  change the brightness and would have to toggle the light using the physical buttons.
+- **min_value** (*Optional*, int, default 0): The lowest dimmer value allowed.  My dimmer had a
+  minimum of 25 and wouldn't even accept anything lower, but this option is available if necessary.
+- **max_value** (*Optional*, int, default 255): The highest dimmer value allowed.  My dimmer had a
+  maximum of 255 which seems like it would be the typical value.
+- All other options from :ref:`Light <config-light>`.
+
+.. note::
+
+    The MCU on the Tuya dimmer handles transitions and gamma correction on its own.
+    Therefore the ``gamma_correct`` setting default is ``1.0`` and the the
+    ``default_transition_length`` parameter is ``0s`` by default.
+
+See Also
+--------
+
+- :doc:`/components/light/index`
+- :apiref:`tuya/light/tuya_light.h`
+- :ghedit:`Edit`

index.rst

@@ -205,9 +205,10 @@ Light Components
 
     RGBWW Light, components/light/rgbww, rgbw.png
     FastLED Light, components/light/fastled, color_lens.svg
-
     NeoPixelBus Light, components/light/neopixelbus, color_lens.svg
+
     Light Partition, components/light/partition, color_lens.svg
+    Tuya Dimmer, components/light/tuya, brightness-medium.svg
     Custom Light, components/light/custom, language-cpp.svg
 
 Looking for WS2811 and similar individually addressable lights? Have a look at the