SDIO 1-bit (and other interfaces) support for ESP-Hosted

[cruzjuniel]

Related area

WiFi/BT via ESP-Hosted

Hardware specification

Any ESP32-P4 board with no on-board ESP-Hosted co-processor, or only connected via 1-bit SDIO

Is your feature request related to a problem?

We'd like to use 1-bit SDIO for ESP-Hosted allowing us to free up some GPIO. This also allows space constrained PCBs to have optional ESP-Hosted coprocessor attachment in exchange for reduced speed, these are cases where using DNM components is also not an option.

Describe the solution you'd like

When using WiFi.setPins(), using d1 to d3 should be allowed to be -1 when not in use and automatically set it to use 1-bit SDIO for ESP-Hosted.

Currently, it doesn't seem to be allowed:

arduino-esp32/cores/esp32/esp32-hal-hosted.c

Lines 136 to 140 in fc8ce8f

	bool hostedSetPins(int8_t clk, int8_t cmd, int8_t d0, int8_t d1, int8_t d2, int8_t d3, int8_t rst) {
	if (clk < 0 || cmd < 0 || d0 < 0 || d1 < 0 || d2 < 0 || d3 < 0 || rst < 0) {
	log_e("All SDIO pins must be defined");
	return false;
	}

Different modes like SPI should be handled as well.

Describe alternatives you've considered

No response

Additional context

No response

I have checked existing list of Feature requests and the Contribution Guide

• I confirm I have checked existing list of Feature requests and Contribution Guide.

[me-no-dev]

we will consult with the hosted team if this is possible and if it makes sense for Arduino

[WanaGo]

I agree, as SDIO 4-bit is only really suitable if you have a PCB with both the ESP32-P4 and ESP32-C6 (etc) on the same board, given the trace and distance requirements. If you have a board with just the ESP32-P4, then SDIO 4-bit isnt really viable, so SDIO 1-bit or SPI are the only other alternatives (or UART if speed is not an issue), and currently they are not supported.

Please add the ability for users to select what interface type they are using, rather than being restricted to SDIO 4-bit only