detect if SPI bus has been initialized (IDFGH-7142)

[morganrallen]

This is a followup on #8642
If a method was provided to detect if the bus was already initialized a decision could be made on calling spi_bus_free before reinitializing. In my situation I have a driver that supports multiple devices that all might not be initialized at the same time. I need a way to see if the bus need initializing (for the first device) or not (for the rest of them).

Describe the solution you'd like
Some function call like bool spi_bus_initialized(spi_host_device_t host_id, spi_bus_config_t *bus_config) or spi_bus_is_initialized for better clarity.

[KaeLL]

I think that's a trivial change, and there may even be an argument for creating an esp_err_t define specifically for denoting that something's already been initialized.
Question, though: are you trying to have each peripheral's driver do all SPI initialization completely independent from one another?

[rtborg]

I'd also appreciate such functionality - for the reason above, each peripheral driver does SPI initialization independent from the others.

[abobija]

Bump 👀

[MassimilianoMontagni]

+1

[morganrallen]

As a workaround I've settled on this method....

  if(spi_bus_get_attr(spi_host) == NULL) {
    err = spi_bus_initialize(spi_host, &buscfg, 2);
  }

It seems to work consistently, but would still be very helpful to have a method that we know will continue to work in the future.

[MassimilianoMontagni]

I'm using idf v 4.4.2 and I don't find any spi_bus_get_attr do I have to import some header or it is no longer available?

[morganrallen]

Also using ~4.4.2, you'll need to include driver/spi_common_internal.h

[MassimilianoMontagni]

Thanks a lot @morganrallen but I still have the issue reported here

[abobija]

Is this resolved? Is there a way to check if SPI is initialized or not?