Documentation: add ESP32 and DevKitC docs

Documentation/platforms/xtensa/esp32/boards/esp32-devkitc/index.rst

@@ -0,0 +1,52 @@
+=============
+ESP32 DevKitC
+=============
+
+The `ESP32 DevKitC <https://docs.espressif.com/projects/esp-idf/en/latest/esp32/hw-reference/modules-and-boards.html#esp32-devkitc-v4>`_ is a development board for the ESP32 SoC from Espressif, based on a ESP-WROOM-32 module. You can find the original V2 version and the newer V4 variant. They are
+pin compatible.
+
+.. list-table::
+   :align: center
+
+   * - .. figure:: esp32-core-board-v2.jpg
+          :align: center
+
+          ESP32 DevKitC/Core V2
+
+     - .. figure:: esp32-devkitc-v4-front.jpg
+          :align: center
+
+          ESP32 DevKitC V4
+
+Features
+========
+
+  - ESP32 WROOM Module
+  - USB-to-UART bridge via micro USB port
+  - Power LED
+  - EN and BOOT buttons (BOOT accessible to user)
+  - SPI FLASH (size varies according to model
+
+Pin Mapping
+===========
+
+.. todo:: To be updated
+
+===== ========== ==========
+Pin   Signal     Notes
+===== ========== ==========
+?     ?          ?
+===== ========== ==========
+
+Configurations
+==============
+
+nsh
+---
+
+Basic NuttShell configuration (console enabled in UART0, exposed via USB connection, at 115200 bps).
+
+wapi
+----
+
+Enables WiFi support

Documentation/platforms/xtensa/esp32/index.rst

@@ -2,13 +2,77 @@
 Espressif ESP32
 ===============
 
+ESP32 series of SoCs from Espressif are single and dual-core chips based on
+Xtensa architecture, with support for Bluetooth and WiFi. 
+
 Toolchain
 =========
 
-OpenOCD
--------
+You can use the prebuilt `compiler <https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/tools/idf-tools.html#xtensa-esp32-elf>`__ for Xtensa architecture and `OpenOCD <https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/tools/idf-tools.html#openocd-esp32>`__ for ESP32 by Espressif. For flashing firmware, you will need to install ``esptool.py`` by running::
+
+    pip install esptool
+
+
+Flashing
+========
+
+Firmware for ESP32 is flashed via the USB/UART interface using the ``esptool.py`` tool. To flash your NuttX firmware simply run::
+
+    make download ESPTOOL_PORT=<port>
+
+where ``<port>`` is typically ``/dev/ttyUSB0`` or similar. You can change the baudrate by passing ``ESPTOOL_BAUD``.
+
+Bootloader and partitions
+-------------------------
+
+ESP32 requires a bootloader to be flashed as well as a set of FLASH partitions. This is only needed the first time
+(or any time you which to modify either of these). An easy way is to use prebuilt binaries for NuttX from `here <https://github.com/espressif/esp-nuttx-bootloader>`_. In there you will find instructions to rebuild these if necessary. 
+Once you downloaded both binaries, you can flash them by adding an ``ESPTOOL_BINDIR`` parameter, pointing to the directiry where these binaries were downloaded::
+
+    make download ESPTOOL_PORT=<port> ESPTOOL_BINDIR=<dir>
+
+.. note:: It is recommended that if this is the first time you are using the board with NuttX that you perform a complete
+   SPI FLASH erase::
+       
+       esptool.py erase_flash
 
 Peripheral Support
 ==================
 
+.. todo:: To be updated
 
+========== ======= =====
+Peripheral Support NOTES
+========== ======= =====
+?          ?       ?
+========== ======= =====
+
+WiFi
+====
+
+A standard network interface will be configured and can be initialized such as::
+
+    ifup wlan0
+    wapi psk wlan0 mypasswd 1
+    wapi essid wlan0 myssid 1
+    renew wlan0
+
+In this case a connection to AP with SSID ``myssid`` is done, using ``mypasswd`` as
+password. IP address is obtained via DHCP using ``renew`` command. You can check
+the result by running ``ifconfig`` afterwards.
+
+.. tip:: Boards usually expose a ``wapi`` defconfig which enables WiFi
+
+Bluetooth
+=========
+
+Bluetooth is not currently supported.
+
+Supported Boards
+================
+
+.. toctree::
+   :glob:
+   :maxdepth: 1
+
+   boards/*/*

NOTICE

@@ -65,3 +65,5 @@ Documentation
 - nRF52832-MDK board pinout image is obtained from MakerDiary GitHub repository,
   under the terms of the MIT license, Copyright (c) 2019 makerdiary.com
 - Sparkfun nRF52832 breakout board image is licensed under CC-BY 2.0 terms
+- Espressif ESP32 DevKitC images are licensed under the terms of Apache 2.0,
+  Copyright (C) 2015-2019 Espressif Systems