i2c

README

Package i2c provides an interface to Linux I2C devices.

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© 2015-2018 Platina Systems, Inc. All rights reserved. Use of this source code is governed by this BSD-style LICENSE.

Documentation

Overview

Package i2c provides an interface to Linux I2C devices.

Index

• Constants
• func Do(index, slave int, f func(bus *Bus) error) (err error)
• type Bus
  • func New(index, address int) (*Bus, error)
  • func (b *Bus) Close() (err error)
  • func (b *Bus) Do(rw RW, command uint8, size SMBusSize, data *SMBusData) (err error)
  • func (b *Bus) ForceSlaveAddress(n int) error
  • func (b *Bus) GetFeatures() (mask FeatureFlag, err error)
  • func (b *Bus) Open(index int) (err error)
  • func (b *Bus) Read(cmd uint8, size SMBusSize, data *SMBusData) (err error)
  • func (bus *Bus) ReadBlock(offset, n int, delay time.Duration) ([]byte, error)
  • func (b *Bus) ReadWrite(rw RW, command uint8, size SMBusSize, data *SMBusData) (err error)
  • func (b *Bus) Send(messages []Message) (err error)
  • func (b *Bus) Set10BitAddressing() error
  • func (b *Bus) Set7BitAddressing() error
  • func (b *Bus) SetRetries(n int) error
  • func (b *Bus) SetSlaveAddress(n int) error
  • func (b *Bus) SetTimeout(n int) error
  • func (b *Bus) Write(cmd uint8, size SMBusSize, data *SMBusData) (err error)
• type FeatureFlag
  • func (x FeatureFlag) String() string
• type IoctlOp
• type Message
• type MessageFlags
• type RW
• type SMBusData
• type SMBusSize

Constants

const BlockMax = SMBusMax + 2

const License = `` /* 15871-byte string literal not displayed */

const SMBusMax = 32

const SendMaxMsgs = 42

const Version = "v1.1.0"

Version format :: v<MAJOR>.<MINOR>.<PATCH>[-rc<CANDIDATE>]

Functions

func Do

func Do(index, slave int, f func(bus *Bus) error) (err error)

Do calls function f with given bus and slave device selected.

Types

type Bus

type Bus struct {
	// contains filtered or unexported fields
}

func New

func New(index, address int) (*Bus, error)

func (*Bus) Close

func (b *Bus) Close() (err error)

func (*Bus) Do

func (b *Bus) Do(rw RW, command uint8, size SMBusSize, data *SMBusData) (err error)

func (*Bus) ForceSlaveAddress

func (b *Bus) ForceSlaveAddress(n int) error

func (*Bus) GetFeatures

func (b *Bus) GetFeatures() (mask FeatureFlag, err error)

func (*Bus) Open

func (b *Bus) Open(index int) (err error)

func (*Bus) Read

func (b *Bus) Read(cmd uint8, size SMBusSize, data *SMBusData) (err error)

func (*Bus) ReadBlock

func (bus *Bus) ReadBlock(offset, n int, delay time.Duration) ([]byte, error)

func (*Bus) ReadWrite

func (b *Bus) ReadWrite(rw RW, command uint8, size SMBusSize, data *SMBusData) (err error)

func (*Bus) Send

func (b *Bus) Send(messages []Message) (err error)

func (*Bus) Set10BitAddressing

func (b *Bus) Set10BitAddressing() error

func (*Bus) Set7BitAddressing

func (b *Bus) Set7BitAddressing() error

func (*Bus) SetRetries

func (b *Bus) SetRetries(n int) error

func (*Bus) SetSlaveAddress

func (b *Bus) SetSlaveAddress(n int) error

func (*Bus) SetTimeout

func (b *Bus) SetTimeout(n int) error

func (*Bus) Write

func (b *Bus) Write(cmd uint8, size SMBusSize, data *SMBusData) (err error)

type FeatureFlag

type FeatureFlag uint32

Functionality (features)

const (
	I2C                    FeatureFlag = 0x00000001
	TenBit_Address         FeatureFlag = 0x00000002
	Protocol_Mangling      FeatureFlag = 0x00000004 /* I2C_M_IGNORE_NAK etc. */
	SMBUS_PEC              FeatureFlag = 0x00000008
	No_Start               FeatureFlag = 0x00000010 /* I2C_M_NOSTART */
	Slave                  FeatureFlag = 0x00000020
	SMBUS_Block_Proc_Call  FeatureFlag = 0x00008000 /* SMBus 2.0 */
	SMBUS_Quick            FeatureFlag = 0x00010000
	SMBUS_Read_Byte        FeatureFlag = 0x00020000
	SMBUS_Write_Byte       FeatureFlag = 0x00040000
	SMBUS_Read_Byte_Data   FeatureFlag = 0x00080000
	SMBUS_Write_Byte_Data  FeatureFlag = 0x00100000
	SMBUS_Read_Word_Data   FeatureFlag = 0x00200000
	SMBUS_Write_Word_Data  FeatureFlag = 0x00400000
	SMBUS_Proc_Call        FeatureFlag = 0x00800000
	SMBUS_Read_Block_Data  FeatureFlag = 0x01000000
	SMBUS_Write_Block_Data FeatureFlag = 0x02000000
	SMBUS_Read_I2C_Block   FeatureFlag = 0x04000000 /* I2C-like block xfer with 1-byte register address. */
	SMBUS_Write_I2C_Block  FeatureFlag = 0x08000000
)

func (FeatureFlag) String

func (x FeatureFlag) String() string

type IoctlOp

type IoctlOp uintptr

/dev/i2c-X ioctl commands. The ioctl's parameter is always an unsigned long, except for:

• I2C_FUNCS, takes pointer to an unsigned long
• I2C_RDWR, takes pointer to struct i2c_rdwr_ioctl_data
• I2C_SMBUS, takes pointer to struct i2c_smbus_ioctl_data

const (
	I2C_RETRIES     IoctlOp = 0x0701 /* number of times a device address should be polled when not acknowledging */
	I2C_TIMEOUT     IoctlOp = 0x0702 /* Set timeout in units of 10 ms */
	I2C_SLAVE       IoctlOp = 0x0703 /* Use this slave address */
	I2C_SLAVE_FORCE IoctlOp = 0x0706 /* Use this slave address, even if it is already in use by a driver. */
	I2C_TENBIT      IoctlOp = 0x0704 /* 0 for 7 bit addrs, != 0 for 10 bit */
	I2C_FUNCS       IoctlOp = 0x0705 /* Get the adapter functionality mask */
	I2C_RDWR        IoctlOp = 0x0707 /* Combined R/W transfer (one STOP only) */
	I2C_PEC         IoctlOp = 0x0708 /* != 0 to use PEC with SMBus */
	I2C_SMBUS       IoctlOp = 0x0720 /* SMBus transfer */
)

type Message

type Message struct {
	Address uint16
	Flags   MessageFlags
	Data    []byte
}

type MessageFlags

type MessageFlags uint16

const (
	ReadData     MessageFlags = 0x0001 /* read data, from slave to master; else write */
	TenBit       MessageFlags = 0x0010 /* this is a ten bit chip address */
	Stop         MessageFlags = 0x8000 /* if feature Protocol_Mangling */
	NoStart      MessageFlags = 0x4000 /* if feature No_Start */
	Rev_Dir_Addr MessageFlags = 0x2000 /* if feature Protocol_Mangling */
	Ignore_NAK   MessageFlags = 0x1000 /* if feature Protocol_Mangling */
	No_Read_ACK  MessageFlags = 0x0800 /* if feature Protocol_Mangling */
	Recv_Len     MessageFlags = 0x0400 /* length will be first received byte */
)

type RW

type RW int

const (
	Write RW = iota
	Read
)

type SMBusData

type SMBusData [BlockMax]byte

Byte_Data

type SMBusSize

type SMBusSize uint32

SMBus transaction types (size parameter in the above functions)

Note: these no longer correspond to the (arbitrary) PIIX4 internal codes!

const (
	// This sends a single bit to the device, at the place of the Rd/Wr bit.
	Quick SMBusSize = 0

	// This reads a single byte from a device, without specifying a device register.
	Byte SMBusSize = 1

	// This reads a single byte from a device, from a designated register.
	// The register is specified through the Comm byte.
	ByteData SMBusSize = 2

	// As above but 2 bytes of data.
	WordData SMBusSize = 3

	// This command selects a device register (through the Comm byte), sends
	// 16 bits of data to it, and reads 16 bits of data in return.
	ProcCall SMBusSize = 4

	// This command reads/writes a block of up to 32 bytes from a device, from a
	// designated register that is specified through the Comm byte. The amount
	// of data is specified by first byte of data.
	BlockData SMBusSize = 5

	I2CBlockBroken SMBusSize = 6

	// This command selects a device register (through the Comm byte), sends
	// 1 to 31 bytes of data to it, and reads 1 to 31 bytes of data in return.
	// SMBus 2.0
	BlockProcCall SMBusSize = 7

	I2CBlockData SMBusSize = 8
)