Make a start on generic peripheral and bus drivers to provide
meta-functionality regardless of platform.
On the one hand this simply provides...
- bitbang i2c on top of esp-idf gpio apis
- ssd1306 oled chip driver as found on Heltec WB32
- modifications to the minimal example test for esp32 to use that
... on the other hand, those capabilities are provided by creating:
- an abstract i2c class object
- an abstract gpio class object
- i2c class implementation using the abstract gpio for bitbang
- an abstract display class object
- an abstract display state (brightness, animated change,
on/off/init tracking, autodim after inactive, auto-off /
blanking after inactive)
... with the intention, eg, you only have to add a platform
implementation for the gpio to be able to use the i2c-based
display drivers and state handling, and i2c bitbang, without
any other modifications.
Esp-idf has an improved but still kind of abused cmake-
based build system now.
If we see ESP_PLATFORM coming as a cmake var, we can know we
are being built from inside the esp-idf config system.
Leave the existing esp32 arrangements alone but triggered off
ESP_PLATFORM, adapt to use the cross toolchain file and
various quirks automatically.
In this way you can build lws a part of your project in a
much cleaner way.
Prepare a minimal esp32 test app for use in Sai
Adapt .sai.json to build for esp32
