Documentation/driver-api/i2c.rst

4 I\ :sup:`2`\ C (or without fancy typography, "I2C") is an acronym for
5 the "Inter-IC" bus, a simple bus protocol which is widely used where low
7 some vendors use another name (such as "Two-Wire Interface", TWI) for
8 the same bus. I2C only needs two signals (SCL for clock, SDA for data),
10 I2C devices use seven bit addresses, and bus speeds of up to 400 kHz;
12 I2C is a multi-master bus; open drain signaling is used to arbitrate
16 The Linux I2C programming interfaces support the master side of bus
18 structured around two kinds of driver, and two kinds of device. An I2C
22 I2C bus segment it manages. On each I2C bus segment will be I2C devices
26 are functions to perform various I2C protocol operations; at this writing
29 The System Management Bus (SMBus) is a sibling protocol. Most SMBus
30 systems are also I2C conformant. The electrical constraints are tighter
32 Controllers that support I2C can also support most SMBus operations, but
33 SMBus controllers don't support all the protocol options that an I2C
35 operations, either using I2C primitives or by issuing SMBus commands to
36 i2c_adapter devices which don't support those I2C operations.
38 .. kernel-doc:: include/linux/i2c.h
41 .. kernel-doc:: drivers/i2c/i2c-boardinfo.c
44 .. kernel-doc:: drivers/i2c/i2c-core-base.c
47 .. kernel-doc:: drivers/i2c/i2c-core-smbus.c