spi: added spi feature for all bbb and rpi

descriptor.go

@@ -14,6 +14,7 @@ type Descriptor struct {
 	GPIODriver func() GPIODriver
 	I2CDriver  func() I2CDriver
 	LEDDriver  func() LEDDriver
+	SPIDriver  func() SPIDriver
 }
 
 // The Describer type is a Descriptor provider.

host/bbb/bbb.go

@@ -94,6 +94,8 @@ var ledMap = embd.LEDMap{
 	"beaglebone:green:usr3": []string{"3", "USR3", "usr3"},
 }
 
+var spiDeviceMinor = byte(1)
+
 func ensureFeatureEnabled(id string) error {
 	pattern := "/sys/devices/bone_capemgr.*/slots"
 	file, err := embd.FindFirstMatchingFile(pattern)
@@ -165,6 +167,9 @@ func init() {
 			LEDDriver: func() embd.LEDDriver {
 				return embd.NewLEDDriver(ledMap, generic.NewLED)
 			},
+			SPIDriver: func() embd.SPIDriver {
+				return embd.NewSPIDriver(spiDeviceMinor, generic.NewSPIBus)
+			},
 		}
 	})
 }

host/generic/spibus.go

@@ -0,0 +1,233 @@
+package generic
+
+import (
+	"fmt"
+	"os"
+	"sync"
+	"syscall"
+	"unsafe"
+
+	"github.com/golang/glog"
+	"github.com/kidoman/embd"
+)
+
+const (
+	SPI_IOC_WR_MODE          = 0x40016B01
+	SPI_IOC_WR_BITS_PER_WORD = 0x40016B03
+	SPI_IOC_WR_MAX_SPEED_HZ  = 0x40046B04
+
+	SPI_IOC_RD_MODE          = 0x80016B01
+	SPI_IOC_RD_BITS_PER_WORD = 0x80016B03
+	SPI_IOC_RD_MAX_SPEED_HZ  = 0x80046B04
+
+	SPI_IOC_MESSAGE_0   = 1073769216 //0x40006B00
+	SPI_IOC_INCREMENTER = 2097152    //0x200000
+
+	DEFAULT_DELAYMS   = uint16(0)
+	DEFAULT_SPI_BPW   = uint8(8)
+	DEFAULT_SPI_SPEED = uint32(1000000)
+)
+
+type spiIocTransfer struct {
+	tx_buf uint64
+	rx_buf uint64
+
+	length        uint32
+	speed_hz      uint32
+	delay_usecs   uint16
+	bits_per_word uint8
+}
+
+type spiBus struct {
+	file *os.File
+
+	spiDevMinor byte
+
+	channel byte
+	mode    byte
+	speed   int
+	bpw     int
+	delayms int
+
+	mu sync.Mutex
+
+	spiTransferData spiIocTransfer
+	initialized     bool
+}
+
+func spi_ioc_message_n(n uint32) uint32 {
+	return (SPI_IOC_MESSAGE_0 + (n * SPI_IOC_INCREMENTER))
+}
+
+func NewSPIBus(spiDevMinor, mode, channel byte, speed, bpw, delay int) embd.SPIBus {
+	return &spiBus{
+		spiDevMinor: spiDevMinor,
+		mode:        mode,
+		channel:     channel,
+		speed:       speed,
+		bpw:         bpw,
+		delayms:     delay,
+	}
+}
+
+func (b *spiBus) init() error {
+	if b.initialized {
+		return nil
+	}
+
+	var err error
+	if b.file, err = os.OpenFile(fmt.Sprintf("/dev/spidev%v.%v", b.spiDevMinor, b.channel), os.O_RDWR, os.ModeExclusive); err != nil {
+		return err
+	}
+
+	err = b.setMode()
+	if err != nil {
+		return err
+	}
+
+	b.spiTransferData = spiIocTransfer{}
+
+	err = b.setSpeed()
+	if err != nil {
+		return err
+	}
+
+	err = b.setBpw()
+	if err != nil {
+		return err
+	}
+
+	b.setDelay()
+
+	glog.V(2).Infof("spi: bus %v initialized", b.channel)
+
+	b.initialized = true
+	return nil
+
+}
+
+func (b *spiBus) setMode() error {
+	var mode = uint8(b.mode)
+	var err error
+	glog.V(3).Infof("spi: setting spi mode to %v", mode)
+
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), SPI_IOC_WR_MODE, uintptr(unsafe.Pointer(&mode)))
+	if errno != 0 {
+		err = syscall.Errno(errno)
+		glog.V(3).Infof("spi: failed to set mode due to %v", err.Error())
+		return err
+	}
+	glog.V(3).Infof("spi: mode set to %v", mode)
+	return nil
+}
+
+func (b *spiBus) setSpeed() error {
+	var speed uint32
+	if b.speed > 0 {
+		speed = uint32(b.speed)
+	} else {
+		speed = DEFAULT_SPI_SPEED
+	}
+
+	glog.V(3).Infof("spi: setting spi speed_max to %v", speed)
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), SPI_IOC_WR_MAX_SPEED_HZ, uintptr(unsafe.Pointer(&speed)))
+	if errno != 0 {
+		err := syscall.Errno(errno)
+		glog.V(3).Infof("spi: failed to set speed_max due to %v", err.Error())
+		return err
+	}
+	glog.V(3).Infof("spi: speed_max set to %v", speed)
+	b.spiTransferData.speed_hz = speed
+
+	return nil
+}
+
+func (b *spiBus) setBpw() error {
+	var bpw uint8
+
+	if b.bpw > 0 {
+		bpw = uint8(b.bpw)
+	} else {
+		bpw = DEFAULT_SPI_BPW
+	}
+
+	glog.V(3).Infof("spi: setting spi bpw to %v", bpw)
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), SPI_IOC_WR_BITS_PER_WORD, uintptr(unsafe.Pointer(&bpw)))
+	if errno != 0 {
+		err := syscall.Errno(errno)
+		glog.V(3).Infof("spi: failed to set bpw due to %v", err.Error())
+		return err
+	}
+	glog.V(3).Infof("spi: bpw set to %v", bpw)
+	b.spiTransferData.bits_per_word = uint8(bpw)
+	return nil
+}
+
+func (b *spiBus) setDelay() {
+	var delay uint16
+
+	if b.delayms > 0 {
+		delay = uint16(b.delayms)
+	} else {
+		delay = DEFAULT_DELAYMS
+	}
+	glog.V(3).Infof("spi: delay_ms set to %v", delay)
+	b.spiTransferData.delay_usecs = delay
+}
+
+func (b *spiBus) TransferAndRecieveData(dataBuffer []uint8) error {
+	len := len(dataBuffer)
+	dataCarrier := b.spiTransferData
+
+	dataCarrier.length = uint32(len)
+	dataCarrier.tx_buf = uint64(uintptr(unsafe.Pointer(&dataBuffer[0])))
+	dataCarrier.rx_buf = uint64(uintptr(unsafe.Pointer(&dataBuffer[0])))
+
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), uintptr(spi_ioc_message_n(1)), uintptr(unsafe.Pointer(&dataCarrier)))
+	if errno != 0 {
+		err := syscall.Errno(errno)
+		glog.V(3).Infof("spi: failed to read due to %v", err.Error())
+		return err
+	}
+	return nil
+}
+
+func (b *spiBus) ReceiveData(len int) ([]uint8, error) {
+	data := make([]uint8, len)
+	var err error
+	err = b.TransferAndRecieveData(data)
+	if err != nil {
+		return nil, err
+	}
+	return data, nil
+}
+
+func (b *spiBus) TransferAndReceiveByte(data byte) (byte, error) {
+	d := make([]uint8, 1)
+	d[0] = uint8(data)
+	err := b.TransferAndRecieveData(d)
+	if err != nil {
+		return 0, err
+	}
+	return d[0], nil
+}
+
+func (b *spiBus) ReceiveByte() (byte, error) {
+	d := make([]uint8, 1)
+	err := b.TransferAndRecieveData(d)
+	if err != nil {
+		return 0, err
+	}
+	return byte(d[0]), nil
+}
+
+func (b *spiBus) Close() error {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if !b.initialized {
+		return nil
+	}
+
+	return b.file.Close()
+}

host/rpi/rpi.go

@@ -13,6 +13,8 @@ import (
 	"github.com/kidoman/embd/host/generic"
 )
 
+var spiDeviceMinor = byte(0)
+
 var rev1Pins = embd.PinMap{
 	&embd.PinDesc{ID: "P1_3", Aliases: []string{"0", "GPIO_0", "SDA", "I2C0_SDA"}, Caps: embd.CapDigital | embd.CapI2C, DigitalLogical: 0},
 	&embd.PinDesc{ID: "P1_5", Aliases: []string{"1", "GPIO_1", "SCL", "I2C0_SCL"}, Caps: embd.CapDigital | embd.CapI2C, DigitalLogical: 1},
@@ -74,6 +76,9 @@ func init() {
 			LEDDriver: func() embd.LEDDriver {
 				return embd.NewLEDDriver(ledMap, generic.NewLED)
 			},
+			SPIDriver: func() embd.SPIDriver {
+				return embd.NewSPIDriver(spiDeviceMinor, generic.NewSPIBus)
+			},
 		}
 	})
 }

samples/spisample.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/kidoman/embd"
+
+	_ "github.com/kidoman/embd/host/all"
+)
+
+func main() {
+	var err error
+	err = embd.InitSPI()
+	if err != nil {
+		panic(err)
+	}
+	defer embd.CloseSPI()
+
+	spiBus := embd.NewSPIBus(embd.SPI_MODE_0, 0, 1000000, 8, 0)
+	defer spiBus.Close()
+
+	dataBuf := make([]uint8, 3)
+	dataBuf[0] = uint8(1)
+	dataBuf[1] = uint8(2)
+	dataBuf[2] = uint8(3)
+
+	err = spiBus.TransferAndRecieveData(dataBuf)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("Recived data is: %v", dataBuf)
+
+	dataReceived, err := spiBus.ReceiveData(3)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("Recived data is: %v", dataReceived)
+
+	dataByte := byte(1)
+	receivedByte, err := spiBus.TransferAndReceiveByte(dataByte)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Println("Recived byte is: %v", receivedByte)
+
+	receivedByte, err = spiBus.ReceiveByte()
+	if err != nil {
+		panic(err)
+	}
+	fmt.Println("Recived byte is: %v", receivedByte)
+}

spi.go

@@ -0,0 +1,64 @@
+package embd
+
+const (
+	spi_cpha = 0x01
+	spi_cpol = 0x02
+
+	SPI_MODE_0 = (0 | 0)
+	SPI_MODE_1 = (0 | spi_cpha)
+	SPI_MODE_2 = (spi_cpol | 0)
+	SPI_MODE_3 = (spi_cpol | spi_cpha)
+)
+
+type SPIBus interface {
+	TransferAndRecieveData(dataBuffer []uint8) error
+
+	ReceiveData(len int) ([]uint8, error)
+
+	TransferAndReceiveByte(data byte) (byte, error)
+
+	ReceiveByte() (byte, error)
+
+	Close() error
+}
+
+type SPIDriver interface {
+	Bus(byte, byte, int, int, int) SPIBus
+
+	Close() error
+}
+
+var spiDriverInitialized bool
+var spiDriverInstance SPIDriver
+
+func InitSPI() error {
+	if spiDriverInitialized {
+		return nil
+	}
+
+	desc, err := DescribeHost()
+	if err != nil {
+		return err
+	}
+
+	if desc.SPIDriver == nil {
+		return ErrFeatureNotSupported
+	}
+
+	spiDriverInstance = desc.SPIDriver()
+	spiDriverInitialized = true
+
+	return nil
+}
+
+func CloseSPI() error {
+	return spiDriverInstance.Close()
+}
+
+func NewSPIBus(mode, channel byte, speed, bpw, delay int) SPIBus {
+	if err := InitSPI(); err != nil {
+		panic(err)
+	}
+
+	return spiDriverInstance.Bus(mode, channel, speed, bpw, delay)
+}

spidriver.go

@@ -0,0 +1,38 @@
+package embd
+
+import "sync"
+
+type spiBusFactory func(byte, byte, byte, int, int, int) SPIBus
+
+type spiDriver struct {
+	spiDevMinor byte
+
+	busMap     map[byte]SPIBus
+	busMapLock sync.Mutex
+
+	spf spiBusFactory
+}
+
+func NewSPIDriver(spiDevMinor byte, sbf spiBusFactory) SPIDriver {
+	return &spiDriver{
+		spiDevMinor: spiDevMinor,
+		spf:         sbf,
+	}
+}
+
+func (s *spiDriver) Bus(mode, channel byte, speed, bpw, delay int) SPIBus {
+	s.busMapLock.Lock()
+	defer s.busMapLock.Unlock()
+
+	b := s.spf(s.spiDevMinor, mode, channel, speed, bpw, delay)
+	s.busMap[channel] = b
+	return b
+}
+
+func (s *spiDriver) Close() error {
+	for _, b := range s.busMap {
+		b.Close()
+	}
+
+	return nil
+}