Merge branch 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6

---------------------------

What:	i2c_adapter.dev

	i2c_adapter.list

What:	i2c_adapter.list

When:	July 2007

Why:	Superfluous, given i2c_adapter.class_dev:

	  * The "dev" was a stand-in for the physical device node that legacy

	    drivers would not have; but now it's almost always present.  Any

	    remaining legacy drivers must upgrade (they now trigger warnings).

	  * The "list" duplicates class device children.

	The delay in removing this is so upgraded lm_sensors and libsensors

	can get deployed.  (Removal causes minor changes in the sysfs layout,

	notably the location of the adapter type name and parenting the i2c

	client hardware directly from their controller.)

Why:	Superfluous, this list duplicates the one maintained by the driver

	core.

Who:	Jean Delvare <khali@linux-fr.org>,

	David Brownell <dbrownell@users.sourceforge.net>

---------------------------

What:	i2c-ixp2000, i2c-ixp4xx and scx200_i2c drivers

When:	September 2007

Why:	Obsolete. The new i2c-gpio driver replaces all hardware-specific

	I2C-over-GPIO drivers.

Who:	Jean Delvare <khali@linux-fr.org>

---------------------------

  * nForce4 MCP-04             10de:0034

  * nForce4 MCP51              10de:0264

  * nForce4 MCP55              10de:0368

  * nForce4 MCP61              10de:03EB

  * nForce4 MCP65              10de:0446

Datasheet: not publicly available, but seems to be similar to the

           AMD-8111 SMBus 2.0 adapter.

Revision 6, 2005-11-20

Revision 7, 2007-04-19

Jean Delvare <khali@linux-fr.org>

Greg KH <greg@kroah.com>

Technical changes:

* [Driver type] Any driver that was relying on i2c-isa has to be

  converted to a proper isa, platform or pci driver. This is not

  covered by this guide.

* [Includes] Get rid of "version.h" and <linux/i2c-proc.h>.

  Includes typically look like that:

  #include <linux/module.h>

  #include <linux/slab.h>

  #include <linux/jiffies.h>

  #include <linux/i2c.h>

  #include <linux/i2c-isa.h>	/* for ISA drivers */

  #include <linux/hwmon.h>	/* for hardware monitoring drivers */

  #include <linux/hwmon-sysfs.h>

  #include <linux/hwmon-vid.h>	/* if you need VRM support */

  #include <linux/err.h>	/* for class registration */

  #include <asm/io.h>		/* if you have I/O operations */

  Please respect this inclusion order. Some extra headers may be

  required for a given driver (e.g. "lm75.h").

  sensors mailing list <lm-sensors@lm-sensors.org> by providing a

  patch to the Documentation/hwmon/sysfs-interface file.

* [Attach] For I2C drivers, the attach function should make sure

  that the adapter's class has I2C_CLASS_HWMON (or whatever class is

  suitable for your driver), using the following construct:

* [Attach] The attach function should make sure that the adapter's

  class has I2C_CLASS_HWMON (or whatever class is suitable for your

  driver), using the following construct:

  if (!(adapter->class & I2C_CLASS_HWMON))

          return 0;

  ISA-only drivers of course don't need this.

  Call i2c_probe() instead of i2c_detect().

* [Detect] As mentioned earlier, the flags parameter is gone.

  The type_name and client_name strings are replaced by a single

  name string, which will be filled with a lowercase, short string.

  In i2c-only drivers, drop the i2c_is_isa_adapter check, it's

  useless. Same for isa-only drivers, as the test would always be

  true. Only hybrid drivers (which are quite rare) still need it.

  The labels used for error paths are reduced to the number needed.

  It is advised that the labels are given descriptive names such as

  exit and exit_free. Don't forget to properly set err before

=============

I2C (pronounce: I squared C) is a protocol developed by Philips. It is a 

slow two-wire protocol (10-400 kHz), but it suffices for many types of 

devices.

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 a subset of the I2C protocol. Many

modern mainboards have a System Management Bus. There are a lot of 

devices which can be connected to a SMBus; the most notable are modern 

memory chips with EEPROM memories and chips for hardware monitoring.

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 just a special case of the generalized I2C bus, we

can simulate the SMBus protocol on plain I2C busses. The reverse is

regretfully impossible.

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

An Algorithm driver contains general code that can be used for a whole class

of I2C adapters. Each specific adapter driver depends on one algorithm

driver.

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

in this package. See the lm_sensors project http://www.lm-sensors.nu

for device drivers.

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.

Included Bus Drivers

====================