doc: drivers: tcpc: Add USB TCPC API documentation

This commit adds documentation for the
USB Type-C Port Controller (TCPC) APIs.

Signed-off-by: Sam Hurst <sbh1187@gmail.com>

doc/reference/api/overview.rst

@@ -287,6 +287,11 @@ current :ref:`stability level <api_lifecycle>`.
      - 2.5
      - 2.5
 
+   * - :ref:`tcpc_api`
+     - Experimental
+     - 3.1
+     - 3.1
+
    * - :ref:`uart_api`
      - Stable
      - 1.0

doc/reference/peripherals/index.rst

@@ -32,6 +32,7 @@ Peripherals
    rtc.rst
    sensor.rst
    spi.rst
+   tcpc.rst
    uart.rst
    mdio.rst
    watchdog.rst

doc/reference/peripherals/tcpc.rst

@@ -0,0 +1,57 @@
+.. _tcpc_api:
+
+TCPC
+####
+
+Overview
+********
+
+`TCPC <tcpc-specification>`_ (USB Type-C Port Controller)
+The TCPC is a device used to simplify the implementation of a USB-C system
+by providing the following three function:
+
+* VBUS and VCONN control `USB Type-C <usb-type-c-specification>`_:
+  The TCPC may provide a Source device, the mechanism to control VBUS sourcing,
+  and a Sink device, the mechanism to control VBUS sinking. A similar mechanism
+  is provided for the control of VCONN.
+
+* CC control and sensing:
+  The TCPC implements logic for controlling the CC pin pull-up and pull-down
+  resistors. It also provides a way to sense and report what resistors are
+  present on the CC pin.
+
+* Power Delivery message reception and transmission `USB Power Delivery <usb-pd-specification>`_:
+  The TCPC sends and receives messages constructed in the TCPM and places them
+  on the CC lines.
+
+.. _tcpc-api:
+
+TCPC API
+========
+
+The TCPC device driver functions as the liaison between the TCPC device and the
+application software; this is accomplished by the Zephyr's API provided by the
+device driver that's used to  communicate with and control the TCPC device.
+
+Configuration Options
+*********************
+
+Related configuration options:
+
+* :kconfig:option:`CONFIG_USBC_TCPC_DRIVER`
+
+API Reference
+*************
+
+.. doxygengroup:: usb_type_c
+.. doxygengroup:: usb_type_c_port_controller_api
+.. doxygengroup:: usb_power_delivery
+
+.. _tcpc-specification:
+   https://www.usb.org/document-library/usb-type-cr-port-controller-interface-specification
+
+.. _usb-type-c-specification:
+   https://www.usb.org/document-library/usb-type-cr-cable-and-connector-specification-revision-21
+
+.. _usb-pd-specification:
+   https://www.usb.org/document-library/usb-power-delivery