ia64/linux-2.6.18-xen.hg

view Documentation/i2c/summary @ 854:950b9eb27661

usbback: fix urb interval value for interrupt urbs.

Signed-off-by: Noboru Iwamatsu <n_iwamatsu@jp.fujitsu.com>
author Keir Fraser <keir.fraser@citrix.com>
date Mon Apr 06 13:51:20 2009 +0100 (2009-04-06)
parents 831230e53067
children
line source
1 This is an explanation of what i2c is, and what is supported in this package.
3 I2C and SMBus
4 =============
6 I2C (pronounce: I squared C) is a protocol developed by Philips. It is a
7 slow two-wire protocol (10-400 kHz), but it suffices for many types of
8 devices.
10 SMBus (System Management Bus) is a subset of the I2C protocol. Many
11 modern mainboards have a System Management Bus. There are a lot of
12 devices which can be connected to a SMBus; the most notable are modern
13 memory chips with EEPROM memories and chips for hardware monitoring.
15 Because the SMBus is just a special case of the generalized I2C bus, we
16 can simulate the SMBus protocol on plain I2C busses. The reverse is
17 regretfully impossible.
20 Terminology
21 ===========
23 When we talk about I2C, we use the following terms:
24 Bus -> Algorithm
25 Adapter
26 Device -> Driver
27 Client
29 An Algorithm driver contains general code that can be used for a whole class
30 of I2C adapters. Each specific adapter driver depends on one algorithm
31 driver.
32 A Driver driver (yes, this sounds ridiculous, sorry) contains the general
33 code to access some type of device. Each detected device gets its own
34 data in the Client structure. Usually, Driver and Client are more closely
35 integrated than Algorithm and Adapter.
37 For a given configuration, you will need a driver for your I2C bus (usually
38 a separate Adapter and Algorithm driver), and drivers for your I2C devices
39 (usually one driver for each device). There are no I2C device drivers
40 in this package. See the lm_sensors project http://www.lm-sensors.nu
41 for device drivers.
44 Included Bus Drivers
45 ====================
46 Note that only stable drivers are patched into the kernel by 'mkpatch'.
49 Base modules
50 ------------
52 i2c-core: The basic I2C code, including the /proc/bus/i2c* interface
53 i2c-dev: The /dev/i2c-* interface
54 i2c-proc: The /proc/sys/dev/sensors interface for device (client) drivers
56 Algorithm drivers
57 -----------------
59 i2c-algo-8xx: An algorithm for CPM's I2C device in Motorola 8xx processors (NOT BUILT BY DEFAULT)
60 i2c-algo-bit: A bit-banging algorithm
61 i2c-algo-pcf: A PCF 8584 style algorithm
62 i2c-algo-ibm_ocp: An algorithm for the I2C device in IBM 4xx processors (NOT BUILT BY DEFAULT)
64 Adapter drivers
65 ---------------
67 i2c-elektor: Elektor ISA card (uses i2c-algo-pcf)
68 i2c-elv: ELV parallel port adapter (uses i2c-algo-bit)
69 i2c-pcf-epp: PCF8584 on a EPP parallel port (uses i2c-algo-pcf) (NOT mkpatched)
70 i2c-philips-par: Philips style parallel port adapter (uses i2c-algo-bit)
71 i2c-adap-ibm_ocp: IBM 4xx processor I2C device (uses i2c-algo-ibm_ocp) (NOT BUILT BY DEFAULT)
72 i2c-pport: Primitive parallel port adapter (uses i2c-algo-bit)
73 i2c-rpx: RPX board Motorola 8xx I2C device (uses i2c-algo-8xx) (NOT BUILT BY DEFAULT)
74 i2c-velleman: Velleman K8000 parallel port adapter (uses i2c-algo-bit)