embd/i2c.go

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// I2C support.
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package embd
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// I2CBus interface is used to interact with the I2C bus.
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type I2CBus interface {
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// ReadByte reads a byte from the given address.
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ReadByte(addr byte) (value byte, err error)
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// ReadBytes reads a slice of bytes from the given address.
ReadBytes(addr byte, num int) (value []byte, err error)
// WriteByte writes a byte to the given address.
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WriteByte(addr, value byte) error
// WriteBytes writes a slice bytes to the given address.
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WriteBytes(addr byte, value []byte) error
// ReadFromReg reads n (len(value)) bytes from the given address and register.
ReadFromReg(addr, reg byte, value []byte) error
// ReadByteFromReg reads a byte from the given address and register.
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ReadByteFromReg(addr, reg byte) (value byte, err error)
// ReadU16FromReg reads a unsigned 16 bit integer from the given address and register.
ReadWordFromReg(addr, reg byte) (value uint16, err error)
// WriteToReg writes len(value) bytes to the given address and register.
WriteToReg(addr, reg byte, value []byte) error
// WriteByteToReg writes a byte to the given address and register.
WriteByteToReg(addr, reg, value byte) error
// WriteU16ToReg
WriteWordToReg(addr, reg byte, value uint16) error
// Close releases the resources associated with the bus.
Close() error
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}
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// I2CDriver interface interacts with the host descriptors to allow us
// control of I2C communication.
type I2CDriver interface {
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Bus(l byte) I2CBus
// Close releases the resources associated with the driver.
Close() error
}
var i2cDriverInitialized bool
var i2cDriverInstance I2CDriver
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// InitI2C initializes the I2C driver.
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func InitI2C() error {
if i2cDriverInitialized {
return nil
}
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desc, err := DescribeHost()
if err != nil {
return err
}
if desc.I2CDriver == nil {
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return ErrFeatureNotSupported
}
i2cDriverInstance = desc.I2CDriver()
i2cDriverInitialized = true
return nil
}
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// CloseI2C releases resources associated with the I2C driver.
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func CloseI2C() error {
return i2cDriverInstance.Close()
}
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// NewI2CBus returns a I2CBus.
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func NewI2CBus(l byte) I2CBus {
if err := InitI2C(); err != nil {
panic(err)
}
return i2cDriverInstance.Bus(l)
}