I am developing for the RPI Pico and noticed that the definition of the SPI0 & SPI1 variables are pointers to the SPI struct. This differ to the SPI0 definition for generic boards, which is simply a struct. As a result the following code compiles with target=pico but does not compile if target is generic/wasm.

func main() {
	machine.SPI1.Configure(machine.SPIConfig{
		SDO: machine.GP15, // default SDO pin - TX
		SCK: machine.GP14, // default sck pin
		SDI: machine.GP28, // default sdi pin
		Frequency: 10000000,
	})
	driver = max72xx.NewDevice(*machine.SPI1, machine.GP13) // Selector
       // compiler error if target is generic

This is because the declaration of SPI0 is different depending which tag you use:
machine/machine_rp2040_spi.go

// SPI on the RP2040
var (
	SPI0  = &_SPI0
	_SPI0 = SPI{
		Bus: rp.SPI0,
	}
	SPI1  = &_SPI1
	_SPI1 = SPI{
		Bus: rp.SPI1,
	}
)

machine/machine_generic_peripherals.go

var (
	UART0 = hardwareUART0
	UART1 = hardwareUART1
	SPI0  = SPI{0}
	SPI1  = SPI{1}
	I2C0  = &I2C{0}
)

It would be more consistent for rp2040 SPI to also be a struct, not a pointer. unless you know a particular reason why this is like that.
Happy to submit a change request if the change makes sense.