Documentation/i2c/smbus-protocol.rst

2 The SMBus Protocol
5 The following is a summary of the SMBus protocol. It applies to
10 Some adapters understand only the SMBus (System Management Bus) protocol,
12 only the same subset, which makes it possible to put them on an SMBus.
14 If you write a driver for some I2C device, please try to use the SMBus
17 SMBus adapters and I2C adapters (the SMBus command set is automatically
19 handled at all on most pure SMBus adapters).
21 Below is a list of SMBus protocol operations, and the functions executing
22 them.  Note that the names used in the SMBus protocol specifications usually
24 single data byte, the functions using SMBus protocol operation names execute
57 SMBus Quick Command
67 SMBus Receive Byte
75 the previous SMBus command::
82 SMBus Send Byte
97 SMBus Read Byte
110 SMBus Read Word
125 around (not SMBus compliant, but very popular.)
128 SMBus Write Byte
144 SMBus Write Word
159 around (not SMBus compliant, but very popular.)
162 SMBus Process Call
174 SMBus Block Read
191 SMBus Block Write
207 SMBus Block Write - Block Read Process Call
210 SMBus Block Write - Block Read Process Call was introduced in
222 SMBus Host Notify
225 This command is sent from a SMBus device acting as a master to the
226 SMBus host acting as a slave.
236 * I2C bus drivers which support SMBus Host Notify should report
238 * I2C bus drivers trigger SMBus Host Notify by a call to
240 * I2C drivers for devices which can trigger SMBus Host Notify will have
267 SMBus Alert
270 SMBus Alert was introduced in Revision 1.0 of the specification.
272 The SMBus alert protocol allows several SMBus slave devices to share a
273 single interrupt pin on the SMBus master, while still allowing the master
278 * I2C bus drivers which support SMBus alert should call
279   i2c_new_smbus_alert_device() to install SMBus alert support.
280 * I2C drivers for devices which can trigger SMBus alerts should implement
287 The following I2C block transactions are similar to the SMBus Block Read
289 supported by the SMBus layer and are described here for completeness, but
290 they are *NOT* defined by the SMBus specification.
293 but the SMBus layer places a limit of 32 bytes.