SPI: pin configuration is not flexible enough

[bugadani]

Currently, we take Output pins for both MOSI and MISO. This creates some problems with devices like M5CoreS3 SE which uses a full-duplex SPI for the SD card, and a 3-wire simplex SPI setup for the display, reusing the MISO pin as the DC output.

Currently we can't work with this device safely.

cc #2494

[thepeak99]

Hi!

I'm having the same issue with the "Cheap Yellow Display" (https://github.com/witnessmenow/ESP32-Cheap-Yellow-Display), in that board the GPIO39 (an input-only pin in the ESP32) is the MISO for the touch screen, since the .with_miso() function requires a PeripheralOutput... it doesn't work. .with_mosi() also requires a PeripheralOutput but that makes sense of course.

I made a local fork of esp_hal and changed it so that it'll take a PeripheralInput and it works.

Interestingly this is only in the master.rs file... in slave.rs it uses a PeripheralOutput for MISO and a PeripheralInput for MOSI (the input/outpit directions are reversed, which makes sense since it is from the slave's perspective).