rp2: allow SPI transmit-only without SDI (#5437)

* rp2: allow SPI transmit-only without SDI

* ci: rerun

---------

Co-authored-by: rdon <you@example.com>

Author: rdon-key

src/machine/machine_rp2_2040.go

@@ -130,11 +130,11 @@ func (spi *SPI) validPins(config SPIConfig) error {
 	var okSDI, okSDO, okSCK bool
 	switch spi.Bus {
 	case rp.SPI0:
-		okSDI = config.SDI == 0 || config.SDI == 4 || config.SDI == 16 || config.SDI == 20
+		okSDI = config.SDI == NoPin || config.SDI == 0 || config.SDI == 4 || config.SDI == 16 || config.SDI == 20
 		okSDO = config.SDO == 3 || config.SDO == 7 || config.SDO == 19 || config.SDO == 23
 		okSCK = config.SCK == 2 || config.SCK == 6 || config.SCK == 18 || config.SCK == 22
 	case rp.SPI1:
-		okSDI = config.SDI == 8 || config.SDI == 12 || config.SDI == 24 || config.SDI == 28
+		okSDI = config.SDI == NoPin || config.SDI == 8 || config.SDI == 12 || config.SDI == 24 || config.SDI == 28
 		okSDO = config.SDO == 11 || config.SDO == 15 || config.SDO == 27
 		okSCK = config.SCK == 10 || config.SCK == 14 || config.SCK == 26
 	}

src/machine/machine_rp2_2350a.go

@@ -21,11 +21,11 @@ func (spi *SPI) validPins(config SPIConfig) error {
 	var okSDI, okSDO, okSCK bool
 	switch spi.Bus {
 	case rp.SPI0:
-		okSDI = config.SDI == 0 || config.SDI == 4 || config.SDI == 16 || config.SDI == 20
+		okSDI = config.SDI == NoPin || config.SDI == 0 || config.SDI == 4 || config.SDI == 16 || config.SDI == 20
 		okSDO = config.SDO == 3 || config.SDO == 7 || config.SDO == 19 || config.SDO == 23
 		okSCK = config.SCK == 2 || config.SCK == 6 || config.SCK == 18 || config.SCK == 22
 	case rp.SPI1:
-		okSDI = config.SDI == 8 || config.SDI == 12 || config.SDI == 24 || config.SDI == 28
+		okSDI = config.SDI == NoPin || config.SDI == 8 || config.SDI == 12 || config.SDI == 24 || config.SDI == 28
 		okSDO = config.SDO == 11 || config.SDO == 15 || config.SDO == 27
 		okSCK = config.SCK == 10 || config.SCK == 14 || config.SCK == 26
 	}

src/machine/machine_rp2_2350b.go

@@ -55,11 +55,11 @@ func (spi *SPI) validPins(config SPIConfig) error {
 	var okSDI, okSDO, okSCK bool
 	switch spi.Bus {
 	case rp.SPI0:
-		okSDI = config.SDI == 0 || config.SDI == 4 || config.SDI == 16 || config.SDI == 20 || config.SDI == 32 || config.SDI == 36
+		okSDI = config.SDI == NoPin || config.SDI == 0 || config.SDI == 4 || config.SDI == 16 || config.SDI == 20 || config.SDI == 32 || config.SDI == 36
 		okSDO = config.SDO == 3 || config.SDO == 7 || config.SDO == 19 || config.SDO == 23 || config.SDO == 35 || config.SDO == 39
 		okSCK = config.SCK == 2 || config.SCK == 6 || config.SCK == 18 || config.SCK == 22 || config.SCK == 34 || config.SCK == 38
 	case rp.SPI1:
-		okSDI = config.SDI == 8 || config.SDI == 12 || config.SDI == 24 || config.SDI == 28 || config.SDI == 40 || config.SDI == 44
+		okSDI = config.SDI == NoPin || config.SDI == 8 || config.SDI == 12 || config.SDI == 24 || config.SDI == 28 || config.SDI == 40 || config.SDI == 44
 		okSDO = config.SDO == 11 || config.SDO == 15 || config.SDO == 27 || config.SDO == 31 || config.SDO == 43 || config.SDO == 47
 		okSCK = config.SCK == 10 || config.SCK == 14 || config.SCK == 26 || config.SCK == 30 || config.SCK == 42 || config.SCK == 46
 	}

src/machine/machine_rp2_spi.go

@@ -174,7 +174,9 @@ func (spi *SPI) Configure(config SPIConfig) error {
 	// SPI pin configuration
 	config.SCK.setFunc(fnSPI)
 	config.SDO.setFunc(fnSPI)
-	config.SDI.setFunc(fnSPI)
+	if config.SDI != NoPin {
+		config.SDI.setFunc(fnSPI)
+	}
 
 	return spi.initSPI(config)
 }