drivers/flash: restore previous calls directly to machine package until we implement SetClockSpeed()

Signed-off-by: deadprogram <ron@hybridgroup.com>

flash/flash.go

@@ -135,12 +135,12 @@ func (dev *Device) Configure(config *DeviceConfig) (err error) {
 	// Speed up to max device frequency
 	// I propose a check here for max frequency, but not put that functionality directly into the driver.
 	// Either that or we have to change the signature of the SPI interface in the machine package itself.
-	// if dev.attrs.MaxClockSpeedMHz > 0 {
-	// 	err := dev.trans.setClockSpeed(uint32(dev.attrs.MaxClockSpeedMHz) * 1e6)
-	// 	if err != nil {
-	// 		return err
-	// 	}
-	// }
+	if dev.attrs.MaxClockSpeedMHz > 0 {
+		err := dev.trans.setClockSpeed(uint32(dev.attrs.MaxClockSpeedMHz) * 1e6)
+		if err != nil {
+			return err
+		}
+	}
 
 	// Enable Quad Mode if available
 	if dev.trans.supportQuadMode() && dev.attrs.QuadEnableBitMask > 0 {

flash/transport_spi.go

@@ -2,13 +2,12 @@ package flash
 
 import (
 	"machine"
-
-	"tinygo.org/x/drivers"
 )
 
 type transport interface {
 	configure(config *DeviceConfig)
 	supportQuadMode() bool
+	setClockSpeed(hz uint32) (err error)
 	runCommand(cmd byte) (err error)
 	readCommand(cmd byte, rsp []byte) (err error)
 	writeCommand(cmd byte, data []byte) (err error)
@@ -19,7 +18,7 @@ type transport interface {
 
 // NewSPI returns a pointer to a flash device that uses a SPI peripheral to
 // communicate with a serial memory chip.
-func NewSPI(spi drivers.SPI, sdo, sdi, sck, cs machine.Pin) *Device {
+func NewSPI(spi *machine.SPI, sdo, sdi, sck, cs machine.Pin) *Device {
 	return &Device{
 		trans: &spiTransport{
 			spi: spi,
@@ -32,7 +31,7 @@ func NewSPI(spi drivers.SPI, sdo, sdi, sck, cs machine.Pin) *Device {
 }
 
 type spiTransport struct {
-	spi drivers.SPI
+	spi *machine.SPI
 	sdo machine.Pin
 	sdi machine.Pin
 	sck machine.Pin
@@ -40,11 +39,31 @@ type spiTransport struct {
 }
 
 func (tr *spiTransport) configure(config *DeviceConfig) {
+	// Configure spi bus
+	tr.setClockSpeed(5000000)
+
 	// Configure chip select pin
 	tr.ss.Configure(machine.PinConfig{Mode: machine.PinOutput})
 	tr.ss.High()
 }
 
+func (tr *spiTransport) setClockSpeed(hz uint32) error {
+	// TODO: un-hardcode this max speed; it is probably a sensible
+	//       default maximum for atsamd and nrf at least
+	if hz > 24*1e6 {
+		hz = 24 * 1e6
+	}
+	tr.spi.Configure(machine.SPIConfig{
+		Frequency: hz,
+		SDI:       tr.sdi,
+		SDO:       tr.sdo,
+		SCK:       tr.sck,
+		LSBFirst:  false,
+		Mode:      0,
+	})
+	return nil
+}
+
 func (tr *spiTransport) supportQuadMode() bool {
 	return false
 }