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diff --git a/Documentation/i2c/summary b/Documentation/i2c/summary deleted file mode 100644 index 13ab076dcd9..00000000000 --- a/Documentation/i2c/summary +++ /dev/null @@ -1,47 +0,0 @@ -I2C and SMBus -============= - -I2C (pronounce: I squared C) is a protocol developed by Philips. It is a -slow two-wire protocol (variable speed, up to 400 kHz), with a high speed -extension (3.4 MHz). It provides an inexpensive bus for connecting many -types of devices with infrequent or low bandwidth communications needs. -I2C is widely used with embedded systems. Some systems use variants that -don't meet branding requirements, and so are not advertised as being I2C. - -SMBus (System Management Bus) is based on the I2C protocol, and is mostly -a subset of I2C protocols and signaling. Many I2C devices will work on an -SMBus, but some SMBus protocols add semantics beyond what is required to -achieve I2C branding. Modern PC mainboards rely on SMBus. The most common -devices connected through SMBus are RAM modules configured using I2C EEPROMs, -and hardware monitoring chips. - -Because the SMBus is mostly a subset of the generalized I2C bus, we can -use its protocols on many I2C systems. However, there are systems that don't -meet both SMBus and I2C electrical constraints; and others which can't -implement all the common SMBus protocol semantics or messages. - - -Terminology -=========== - -When we talk about I2C, we use the following terms: - Bus -> Algorithm - Adapter - Device -> Driver - Client - -An Algorithm driver contains general code that can be used for a whole class -of I2C adapters. Each specific adapter driver either depends on one algorithm -driver, or includes its own implementation. - -A Driver driver (yes, this sounds ridiculous, sorry) contains the general -code to access some type of device. Each detected device gets its own -data in the Client structure. Usually, Driver and Client are more closely -integrated than Algorithm and Adapter. - -For a given configuration, you will need a driver for your I2C bus, and -drivers for your I2C devices (usually one driver for each device). - -At this time, Linux only operates I2C (or SMBus) in master mode; you can't -use these APIs to make a Linux system behave as a slave/device, either to -speak a custom protocol or to emulate some other device. |