[sx127x] Add sx127x component (#4278)

Co-authored-by: Jonathan Swoboda <jonathan.swoboda>
Co-authored-by: J. Nick Koston <nick@koston.org>

Author: swoboda1337

components/images/sx127x-full.png

@@ -1073,6 +1073,7 @@ ESPHome to cellular networks. **Does not encompass Wi-Fi.**
     Remote Transmitter, components/remote_transmitter, remote.svg, dark-invert
     RF Bridge, components/rf_bridge, rf_bridge.jpg
     SIM800L, components/sim800l, sim800l.jpg
+    SX127x, components/sx127x, sx127x.png
 
 Miscellaneous Components
 ------------------------

components/index.rst

@@ -11,7 +11,7 @@ Packet Transport Component
 The purpose of this component is to allow ESPHome nodes to directly communicate with each over a communication channel.
 It permits the state of sensors and binary sensors to be transmitted from one node to another, without the need for a
 central server or broker. The actual transport channel is provided by another component. Currently the supported
-transports are :doc:`/components/udp` and :doc:`/components/uart`.
+transports are :doc:`/components/sx127x`, :doc:`/components/uart` and :doc:`/components/udp`.
 
 Nodes may be *providers* which transmit or broadcast sensor data, or *consumers* which receive sensor data from one or more
 providers. A node may be both a provider and a consumer. Optional security is provided by one or more of:

components/packet_transport/index.rst

@@ -0,0 +1,59 @@
+.. sx127x-packet-transport:
+
+SX127x Packet Transport Platform
+================================
+
+.. seo::
+    :description: Instructions for setting up a sx127x packet transport platform on ESPHome
+    :image: sx127x.png
+    :keywords: sx127x, packet, transport
+
+The :ref:`packet-transport` platform allows ESPHome nodes to directly communicate with each over a
+communication channel. The :doc:`/components/sx127x` implementation of the platform uses FSK, OOK or
+LoRa as a communication medium. See the :ref:`packet-transport` and :ref:`sx127x` for more information.
+
+Example Configuration
+---------------------
+
+.. code-block:: yaml
+
+    # Example configuration entry
+    sx127x:
+      dio0_pin: GPIO26
+      cs_pin: GPIO18
+      rst_pin: GPIO23
+      pa_pin: BOOST
+      pa_power: 8
+      bandwidth: 125_0kHz
+      crc_enable: true
+      frequency: 433920000
+      modulation: LORA
+      rx_start: true
+      sync_value: 0x33
+      spreading_factor: 7
+      coding_rate: CR_4_5
+
+    packet_transport:
+      platform: sx127x
+      sensors:
+        - dht_temp
+
+    sensor:
+      - platform: dht
+          id: dht
+          pin: GPIOXX
+          temperature:
+            name: "Temperature"
+            id: dht_temp
+
+
+See Also
+--------
+
+- :ref:`packet-transport`
+- :doc:`/components/sx127x`
+- :doc:`/components/binary_sensor/packet_transport`
+- :doc:`/components/sensor/packet_transport`
+- :ref:`automation`
+- :apiref:`packet_transport/packet_transport.h`
+- :ghedit:`Edit`