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mirror of https://github.com/kidoman/embd synced 2024-12-22 04:40:04 +01:00

Merge pull request #6 from kunalpowar/spi

This commit is contained in:
Karan Misra 2014-05-22 03:27:31 +05:30
commit c28f7a2de9
11 changed files with 589 additions and 0 deletions

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@ -0,0 +1,45 @@
package mcp3008
import (
"github.com/golang/glog"
"github.com/kidoman/embd"
)
// MCP3008 represents a mcp3008 8bit DAC.
type MCP3008 struct {
Mode byte
Bus embd.SPIBus
}
const (
// SingleMode represents the single-ended mode for the mcp3008.
SingleMode = 1
// DifferenceMode represents the diffenrential mode for the mcp3008.
DifferenceMode = 0
)
// New creates a representation of the mcp3008 convertor
func New(mode byte, bus embd.SPIBus) *MCP3008 {
return &MCP3008{mode, bus}
}
const (
startBit = 1
)
// AnalogValueAt returns the analog value at the given channel of the convertor.
func (m *MCP3008) AnalogValueAt(chanNum int) (int, error) {
var data [3]uint8
data[0] = startBit
data[1] = uint8(m.Mode)<<7 | uint8(chanNum)<<4
data[2] = 0
glog.V(2).Infof("mcp3008: sendingdata buffer %v", data)
if err := m.Bus.TransferAndRecieveData(data[:]); err != nil {
return 0, err
}
return int(uint16(data[1]&0x03)<<8 | uint16(data[2])), nil
}

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@ -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.

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@ -15,6 +15,7 @@ import (
"os"
"strings"
"github.com/golang/glog"
"github.com/kidoman/embd"
"github.com/kidoman/embd/host/generic"
)
@ -94,7 +95,10 @@ var ledMap = embd.LEDMap{
"beaglebone:green:usr3": []string{"3", "USR3", "usr3"},
}
var spiDeviceMinor byte = 1
func ensureFeatureEnabled(id string) error {
glog.V(3).Infof("bbb: enabling feature %v", id)
pattern := "/sys/devices/bone_capemgr.*/slots"
file, err := embd.FindFirstMatchingFile(pattern)
if err != nil {
@ -106,6 +110,7 @@ func ensureFeatureEnabled(id string) error {
}
str := string(bytes)
if strings.Contains(str, id) {
glog.V(3).Infof("bbb: feature %v already enabled", id)
return nil
}
slots, err := os.OpenFile(file, os.O_WRONLY, os.ModeExclusive)
@ -113,6 +118,7 @@ func ensureFeatureEnabled(id string) error {
return err
}
defer slots.Close()
glog.V(3).Infof("bbb: writing %v to slots file", id)
_, err = slots.WriteString(id)
return err
}
@ -153,6 +159,13 @@ func ensureFeatureDisabled(id string) error {
return fmt.Errorf("embd: could not disable feature %q", id)
}
func spiInitializer() error {
if err := ensureFeatureEnabled("BB-SPIDEV0"); err != nil {
return err
}
return nil
}
func init() {
embd.Register(embd.HostBBB, func(rev int) *embd.Descriptor {
return &embd.Descriptor{
@ -165,6 +178,9 @@ func init() {
LEDDriver: func() embd.LEDDriver {
return embd.NewLEDDriver(ledMap, generic.NewLED)
},
SPIDriver: func() embd.SPIDriver {
return embd.NewSPIDriver(spiDeviceMinor, generic.NewSPIBus, spiInitializer)
},
}
})
}

245
host/generic/spibus.go Normal file
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@ -0,0 +1,245 @@
package generic
import (
"fmt"
"os"
"sync"
"syscall"
"unsafe"
"github.com/golang/glog"
"github.com/kidoman/embd"
)
const (
spiIOCWrMode = 0x40016B01
spiIOCWrBitsPerWord = 0x40016B03
spiIOCWrMaxSpeedHz = 0x40046B04
spiIOCRdMode = 0x80016B01
spiIOCRdBitsPerWord = 0x80016B03
spiIOCRdMaxSpeedHz = 0x80046B04
spiIOCMessage0 = 1073769216 //0x40006B00
spiIOCIncrementor = 2097152 //0x200000
defaultDelayms = 0
defaultSPIBPW = 8
defaultSPISpeed = 1000000
)
type spiIOCTransfer struct {
txBuf uint64
rxBuf uint64
length uint32
speedHz uint32
delayus uint16
bitsPerWord 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
initializer func() error
}
func spiIOCMessageN(n uint32) uint32 {
return (spiIOCMessage0 + (n * spiIOCIncrementor))
}
func NewSPIBus(spiDevMinor, mode, channel byte, speed, bpw, delay int, i func() error) embd.SPIBus {
return &spiBus{
spiDevMinor: spiDevMinor,
mode: mode,
channel: channel,
speed: speed,
bpw: bpw,
delayms: delay,
initializer: i,
}
}
func (b *spiBus) init() error {
if b.initialized {
return nil
}
if b.initializer != nil {
if err := b.initializer(); err != nil {
return err
}
}
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
}
glog.V(3).Infof("spi: sucessfully opened file /dev/spidev%v.%v", b.spiDevMinor, b.channel)
if err = b.setMode(); err != nil {
return err
}
b.spiTransferData = spiIOCTransfer{}
if err = b.setSpeed(); err != nil {
return err
}
if err = b.setBPW(); err != nil {
return err
}
b.setDelay()
glog.V(2).Infof("spi: bus %v initialized", b.channel)
glog.V(3).Infof("spi: bus %v initialized with spiIOCTransfer as %v", b.channel, b.spiTransferData)
b.initialized = true
return nil
}
func (b *spiBus) setMode() error {
var mode = uint8(b.mode)
glog.V(3).Infof("spi: setting spi mode to %v", mode)
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), spiIOCWrMode, 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 = defaultSPISpeed
if b.speed > 0 {
speed = uint32(b.speed)
}
glog.V(3).Infof("spi: setting spi speedMax to %v", speed)
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), spiIOCWrMaxSpeedHz, uintptr(unsafe.Pointer(&speed)))
if errno != 0 {
err := syscall.Errno(errno)
glog.V(3).Infof("spi: failed to set speedMax due to %v", err.Error())
return err
}
glog.V(3).Infof("spi: speedMax set to %v", speed)
b.spiTransferData.speedHz = speed
return nil
}
func (b *spiBus) setBPW() error {
var bpw uint8 = defaultSPIBPW
if b.bpw > 0 {
bpw = uint8(b.bpw)
}
glog.V(3).Infof("spi: setting spi bpw to %v", bpw)
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), spiIOCWrBitsPerWord, 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.bitsPerWord = uint8(bpw)
return nil
}
func (b *spiBus) setDelay() {
var delay uint16 = defaultDelayms
if b.delayms > 0 {
delay = uint16(b.delayms)
}
glog.V(3).Infof("spi: delayms set to %v", delay)
b.spiTransferData.delayus = delay
}
func (b *spiBus) TransferAndRecieveData(dataBuffer []uint8) error {
if err := b.init(); err != nil {
return err
}
len := len(dataBuffer)
dataCarrier := b.spiTransferData
dataCarrier.length = uint32(len)
dataCarrier.txBuf = uint64(uintptr(unsafe.Pointer(&dataBuffer[0])))
dataCarrier.rxBuf = uint64(uintptr(unsafe.Pointer(&dataBuffer[0])))
glog.V(3).Infof("spi: sending dataBuffer %v with carrier %v", dataBuffer, dataCarrier)
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), uintptr(spiIOCMessageN(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
}
glog.V(3).Infof("spi: read into dataBuffer %v", dataBuffer)
return nil
}
func (b *spiBus) ReceiveData(len int) ([]uint8, error) {
if err := b.init(); err != nil {
return nil, err
}
data := make([]uint8, len)
if err := b.TransferAndRecieveData(data); err != nil {
return nil, err
}
return data, nil
}
func (b *spiBus) TransferAndReceiveByte(data byte) (byte, error) {
if err := b.init(); err != nil {
return 0, err
}
d := [1]uint8{uint8(data)}
if err := b.TransferAndRecieveData(d[:]); err != nil {
return 0, err
}
return d[0], nil
}
func (b *spiBus) ReceiveByte() (byte, error) {
if err := b.init(); err != nil {
return 0, err
}
var d [1]uint8
if err := b.TransferAndRecieveData(d[:]); 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()
}

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@ -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, nil)
},
}
})
}

3
samples/.gitignore vendored
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@ -23,3 +23,6 @@ tmp006
universalblinker
us020
watersensor
spi
mcp3008
spimcp3008

45
samples/mcp3008.go Normal file
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@ -0,0 +1,45 @@
// +build ignore
// this sample uses the mcp3008 package to interface with the 8-bit ADC and works without code change on bbb and rpi
package main
import (
"flag"
"fmt"
"time"
"github.com/kidoman/embd"
"github.com/kidoman/embd/convertors/mcp3008"
_ "github.com/kidoman/embd/host/all"
)
const (
channel = 0
speed = 1000000
bpw = 8
delay = 0
)
func main() {
flag.Parse()
fmt.Println("this is a sample code for mcp3008 10bit 8 channel ADC")
if err := embd.InitSPI(); err != nil {
panic(err)
}
defer embd.CloseSPI()
spiBus := embd.NewSPIBus(embd.SPIMode0, channel, speed, bpw, delay)
defer spiBus.Close()
adc := mcp3008.New(mcp3008.SingleMode, spiBus)
for i := 0; i < 20; i++ {
time.Sleep(1 * time.Second)
val, err := adc.AnalogValueAt(0)
if err != nil {
panic(err)
}
fmt.Printf("analog value is: %v\n", val)
}
}

48
samples/spi.go Normal file
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@ -0,0 +1,48 @@
// +build ignore
package main
import (
"fmt"
"github.com/kidoman/embd"
_ "github.com/kidoman/embd/host/all"
)
func main() {
if err := embd.InitSPI(); err != nil {
panic(err)
}
defer embd.CloseSPI()
spiBus := embd.NewSPIBus(embd.SPIMode0, 0, 1000000, 8, 0)
defer spiBus.Close()
dataBuf := [3]uint8{1, 2, 3}
if err := spiBus.TransferAndRecieveData(dataBuf[:]); err != nil {
panic(err)
}
fmt.Println("received data is: %v", dataBuf)
dataReceived, err := spiBus.ReceiveData(3)
if err != nil {
panic(err)
}
fmt.Println("received data is: %v", dataReceived)
dataByte := byte(1)
receivedByte, err := spiBus.TransferAndReceiveByte(dataByte)
if err != nil {
panic(err)
}
fmt.Println("received byte is: %v", receivedByte)
receivedByte, err = spiBus.ReceiveByte()
if err != nil {
panic(err)
}
fmt.Println("received byte is: %v", receivedByte)
}

50
samples/spimcp3008.go Normal file
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@ -0,0 +1,50 @@
// +build ignore
package main
import (
"flag"
"fmt"
"time"
"github.com/kidoman/embd"
_ "github.com/kidoman/embd/host/all"
)
const (
channel = 0
speed = 1000000
bpw = 8
delay = 0
)
func main() {
flag.Parse()
if err := embd.InitSPI(); err != nil {
panic(err)
}
defer embd.CloseSPI()
bus := embd.NewSPIBus(embd.SPIMode0, channel, speed, bpw, delay)
defer bus.Close()
for i := 0; i < 30; i++ {
time.Sleep(1 * time.Second)
val, err := getSensorValue(bus)
if err != nil {
panic(err)
}
fmt.Printf("value is: %v\n", val)
}
}
func getSensorValue(bus embd.SPIBus) (uint16, error) {
data := [3]uint8{1, 128, 0}
var err error
err = bus.TransferAndRecieveData(data[:])
if err != nil {
return uint16(0), err
}
return uint16(data[1]&0x03)<<8 | uint16(data[2]), nil
}

86
spi.go Normal file
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@ -0,0 +1,86 @@
// SPI support.
package embd
const (
spiCpha = 0x01
spiCpol = 0x02
// SPIMode0 represents the mode0 operation (CPOL=0 CPHA=0) of spi.
SPIMode0 = (0 | 0)
// SPIMode1 represents the mode0 operation (CPOL=0 CPHA=1) of spi.
SPIMode1 = (0 | spiCpha)
// SPIMode2 represents the mode0 operation (CPOL=1 CPHA=0) of spi.
SPIMode2 = (spiCpol | 0)
// SPIMode3 represents the mode0 operation (CPOL=1 CPHA=1) of spi.
SPIMode3 = (spiCpol | spiCpha)
)
// SPI interface allows interaction with the SPI bus.
type SPIBus interface {
// TransferAndRecieveData transmits data in a buffer(slice) and receives into it.
TransferAndRecieveData(dataBuffer []uint8) error
// ReceiveData receives data of length len into a slice.
ReceiveData(len int) ([]uint8, error)
// TransferAndReceiveByte transmits a byte data and receives a byte.
TransferAndReceiveByte(data byte) (byte, error)
// ReceiveByte receives a byte data.
ReceiveByte() (byte, error)
// Close releases the resources associated with the bus.
Close() error
}
// SPIDriver interface interacts with the host descriptors to allow us
// control of SPI communication.
type SPIDriver interface {
// Bus returns a SPIBus interface which allows us to use spi functionalities
Bus(byte, byte, int, int, int) SPIBus
// Close cleans up all the initialized SPIbus
Close() error
}
var spiDriverInitialized bool
var spiDriverInstance SPIDriver
// InitSPI initializes the SPI driver.
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
}
// CloseSPI releases resources associated with the SPI driver.
func CloseSPI() error {
return spiDriverInstance.Close()
}
// NewSPIBus returns a SPIBus.
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)
}

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spidriver.go Normal file
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@ -0,0 +1,45 @@
package embd
import "sync"
type spiBusFactory func(byte, byte, byte, int, int, int, func() error) SPIBus
type spiDriver struct {
spiDevMinor byte
initializer func() error
busMap map[byte]SPIBus
busMapLock sync.Mutex
sbf spiBusFactory
}
// NewSPIDriver returns a SPIDriver interface which allows control
// over the SPI bus.
func NewSPIDriver(spiDevMinor byte, sbf spiBusFactory, i func() error) SPIDriver {
return &spiDriver{
spiDevMinor: spiDevMinor,
sbf: sbf,
initializer: i,
}
}
// Bus returns a SPIBus interface which allows us to use spi functionalities
func (s *spiDriver) Bus(mode, channel byte, speed, bpw, delay int) SPIBus {
s.busMapLock.Lock()
defer s.busMapLock.Unlock()
b := s.sbf(s.spiDevMinor, mode, channel, speed, bpw, delay, s.initializer)
s.busMap = make(map[byte]SPIBus)
s.busMap[channel] = b
return b
}
// Close cleans up all the initialized SPIbus
func (s *spiDriver) Close() error {
for _, b := range s.busMap {
b.Close()
}
return nil
}