go-embedded/embd
go-embedded/embd
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spi: added godoc

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This commit is contained in:
kunalpowar 2014-05-08 23:46:09 +05:30
parent dbc97bd15c
commit c42a345a60
1 changed files with 20 additions and 0 deletions
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20
spi.go
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@ -1,27 +1,44 @@
// SPI support.
package embd package embd
const ( const (
spiCpha = 0x01 spiCpha = 0x01
spiCpol = 0x02 spiCpol = 0x02
// SpiMode0 represents the mode0 operation (CPOL=0 CPHA=0) of spi.
SpiMode0 = (0 | 0) SpiMode0 = (0 | 0)
// SpiMode0 represents the mode0 operation (CPOL=0 CPHA=1) of spi.
SpiMode1 = (0 | spiCpha) SpiMode1 = (0 | spiCpha)
// SpiMode0 represents the mode0 operation (CPOL=1 CPHA=0) of spi.
SpiMode2 = (spiCpol | 0) SpiMode2 = (spiCpol | 0)
// SpiMode0 represents the mode0 operation (CPOL=1 CPHA=1) of spi.
SpiMode3 = (spiCpol | spiCpha) SpiMode3 = (spiCpol | spiCpha)
) )
// SPI interface allows interaction with the SPI bus.
type SPIBus interface { type SPIBus interface {
// TransferAndRecieveData transmits data in a buffer(slice) and receives into it.
TransferAndRecieveData(dataBuffer []uint8) error TransferAndRecieveData(dataBuffer []uint8) error
// ReceiveData receives data of length len into a slice.
ReceiveData(len int) ([]uint8, error) ReceiveData(len int) ([]uint8, error)
// TransferAndReceiveByte transmits a byte data and receives a byte.
TransferAndReceiveByte(data byte) (byte, error) TransferAndReceiveByte(data byte) (byte, error)
// ReceiveByte receives a byte data.
ReceiveByte() (byte, error) ReceiveByte() (byte, error)
// Close releases the resources associated with the bus.
Close() error Close() error
} }
// SPIDriver interface interacts with the host descriptors to allow us
// control of SPI communication.
type SPIDriver interface { type SPIDriver interface {
Bus(byte, byte, int, int, int) SPIBus Bus(byte, byte, int, int, int) SPIBus
@ -31,6 +48,7 @@ type SPIDriver interface {
var spiDriverInitialized bool var spiDriverInitialized bool
var spiDriverInstance SPIDriver var spiDriverInstance SPIDriver
// InitSPI initializes the SPI driver.
func InitSPI() error { func InitSPI() error {
if spiDriverInitialized { if spiDriverInitialized {
return nil return nil
@ -51,10 +69,12 @@ func InitSPI() error {
return nil return nil
} }
// CloseSPI releases resources associated with the SPI driver.
func CloseSPI() error { func CloseSPI() error {
return spiDriverInstance.Close() return spiDriverInstance.Close()
} }
// NewSPIBus returns a SPIBus.
func NewSPIBus(mode, channel byte, speed, bpw, delay int) SPIBus { func NewSPIBus(mode, channel byte, speed, bpw, delay int) SPIBus {
if err := InitSPI(); err != nil { if err := InitSPI(); err != nil {
panic(err) panic(err)