The standard rtc-m41t80.c driver cannot be used with the SWARM as it is,
because the board does not provide setup information for the I2C core.  
As a result the bus and the address to probe for the M41T80 chip is not
known.

 Here is a set of changes that fix the problem:

1. swarm-i2c.c -- SWARM I2C board setup, currently for the M41T80 chip on 
   the bus #1 only (there is a MAX6654 temperature sensor on the bus #0 
   which may be added in the future if we have a driver for that chip).

2. The i2c-sibyte.c BCM1250A SMBus controller driver now registers its 
   buses as numbered so that board setup is correctly applied.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Move the check of pre-transaction and post-transaction conditions to
separate functions, and adjust them a bit. Having dedicated functions
for that ensures that errors are handled in a consistent way.

Bit HOST_BUSY of the status register is read-only, so writing to it is
certainly not going to clear it. If this bit is set then we simply
don't want to start the transaction, as it means that somebody else
(ACPI, SMM?) is already using the controller.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

"temp" isn't a terribly well chosen name for a local variable.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Bit BUS_ERR of the status register means that the ICH host controller
lost the arbitration. Report this event as such.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Dumping the register values before and after every transaction was
useful during driver development but now it's only spamming the log.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Struct members udelay and timeout aren't used anywhere, so drop them.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Eric Brower <ebrower@gmail.com>

Improve lost-arbitration handling of PCF8584.  This is necessary for
support of a currently out-of-kernel driver for Sun Microsystems E250
environmental management; perhaps others.
Signed-off-by: Eric Brower <ebrower@gmail.com>
Acked-by: Dan Smolik <marvin@mydatex.cz>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

The legacy pcf8574 and pcf8575 drivers should be avoided
on systems using the new gpiolib code, and generally deprecated
in the same way the legacy pca9539 driver is deprecated.

Also, correct the pca9539 deprecation to match the current name
of the preferred driver:  pca953x, supporting several more chips.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Initialize the pxa i2c bus during subsystem initialization to make it
available during driver initialization (e.g. display powerup for pxafb).
Signed-off-by: Uli Luckas <u.luckas@road.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Enable the IBM I2C driver for all PPC4xx variants by adding
"ibm,iic" to the compatible list. This way all currently available
arch/powerpc 4xx ports can make use of this driver without any changes.
Additionally all "other" compatible entries are removed since they are
not needed anymore.

Currently all 4xx PPC's have the same compatible I2C macro. If at some
time an incompatibility is detected we can take care of this with an
additional property.
Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

The deprecated OCP style driver part is used by the "old" arch/ppc
platform. This platform is scheduled for removal in June/July this year.
This patch now removes the OCP driver part from the IBM I2C driver.
Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

i2c_driver.id_table is mandatory now, so we can simplify
i2c_device_probe() a bit.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

When I2C block reads are not supported by the underlying adapter, use
SMBus read word transactions instead of consecutive byte reads.
Reasons for this change are:

* The consecutive byte read approach is not safe on multi-master buses.

* While consecutive byte reads have less overhead if you only count the
  bytes on the bus, it takes more than twice as many transactions as
  with SMBus read word transactions, and each transaction has a cost:
  taking and releasing the adapter mutex, and for polling drivers,
  waiting for the transaction to complete.

This change yields a significant performance boost at HZ=250 with
EEPROMs on an Intel 82801 bus (basically twice as fast.)

SMBus read word transactions are widely supported so I don't expect
compatibility issues.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

The eeprom driver shouldn't probe i2c buses which don't want to be
probed.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Let general purpose I2C/SMBus bus drivers add SPD to their class. Once
this is done, we will be able to tell the eeprom driver to only probe
for SPD EEPROMs and similar on these buses.

Note that I took a conservative approach here, adding I2C_CLASS_SPD to
many drivers that have no idea whether they can host SPD EEPROMs or not.
This is to make sure that the eeprom driver doesn't stop probing buses
where SPD EEPROMs or equivalent live.

So, bus driver maintainers and users should feel free to remove the SPD
class from drivers those buses never have SPD EEPROMs or they don't
want the eeprom driver to bind to them. Likewise, feel free to add the
SPD class to any bus driver I might have missed.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Let framebuffer drivers set their I2C bus class to DDC. Once this is
done, we will be able to tell the eeprom driver to only probe for
EDID EEPROMs on these buses.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Signed-off-by: Jochen Friedrich <jochen@scram.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Bugfixes to the i2c-cpm driver

- enable correct interrupts (I2CER_TXE instead of I2CER_BUSY)
- replace forgotten iic with i2c
- prefix debug-output on init with 0x and add frequency
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Jochen Friedrich <jochen@scram.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

This driver uses the port of 2.4 code from Vitaly Bordug
<vitb@kernel.crashing.org> and the actual algorithm used by the i2c
driver of the DBox code on cvs.tuxboc.org from Felix Domke
(tmbinc@gmx.net) and Gillem (htoa@gmx.net) converted to an
of_platform_driver. Tested on CPM1 (MPC823 on dbox2 hardware) and
CPM2 (MPC8272).
Signed-off-by: Jochen Friedrich <jochen@scram.de>
Tested-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

This is part of the effort to get rid of the BKL.

[JD: In fact i2c-dev doesn't need more locking than is already done
for the other i2c drivers, so we can simply switch to unlocked_ioctl.]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

New i2c bus driver for the Intel SCH chipsets (AF82US15W, AF82US15L,
AF82UL11L).
Signed-off-by: Alek Du <alek.du@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

i2c_del_driver() can be simplified a bit.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Use list_for_each_entry_safe() in i2c_del_adapter() and i2c_del_driver().
Signed-off-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Fix errorcode to be more descriptive when ioremap fails.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Give a more concrete error code, when the bus is not idle.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Many PC SMBus host controller drivers don't properly handle the case
where they are requested to achieve a transaction they do not support.
Update them so that the consistently print a warning message and
return a single error value in this case.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

The i2c-piix4 driver was used recently as a model to write a new SMBus
host controller driver and this made me realize that the code of this
old driver wasn't exactly good. So, here are many cleanups and minor
fixes to this driver, so that these minor mistakes aren't duplicated
again:

* Delete unused structure.
* Delete needless forward function declaration.
* Properly announce the SMBus host controller as we find it.
* Spell it SMBus not SMB.
* Return -EBUSY instead of -ENODEV when the I/O region is already in
  use.
* Drop useless masks on the 7-bit address and the R/W bit.
* Reject block transaction requests with an invalid block length.
* Check and report block transaction replies with an invalid block
  length.
* Delete a useless comment.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Tighten error paths used by various i2c adapters (mostly x86) so
they return real fault/errno codes instead of a "-1" (which is
most often interpreted as "-EPERM").  Build tested, with eyeball
review.

One minor initial goal is to have adapters consistently return
the code "-ENXIO" when addressing a device doesn't get an ACK
response, at least in the probe paths where they are already
good at stifling related logspam.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Defend the i2c refcount calls against NULL pointers, as is important
(and conventional) for such calls.  Note that none of the current
callers of i2c_use_client() use its return value.

[JD: I hate this but apparently all the other subsystems do it so...]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Provide kerneldoc for most of the I2C and SMBus I/O calls.  Add a
comment summarizing some fault reporting issues which affect the
ability to provide clean fault reports through I2C master transfer
calls.  (Making it hard to precisely specify their return values...)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

That function is actually named i2c_smbus_xfer.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Function i2c_smbus_write_quick has no users left, so we can delete it.

Also update the list of these helper functions which are gone but
could be added back if needed.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

The list of I2C/SMBus bus drivers is growing and it is sometimes
difficult for the users to figure out what drivers they should enable.
By grouping the drivers by type, I hope to make the selection easier.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

More updates to the I2C stack's fault reporting:  make the core stop
returning "-1" (usually "-EPERM") for all faults.  Instead, pass lower
level fault code up the stack, or return some appropriate errno.

This patch happens to touch almost exclusively SMBus calls.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

i2c-core doesn't use seq files, so doesn't need to include
<linux/seq_file.h>.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Create Documentation/i2c/fault-codes to help standardize
fault/error code usage in the I2C stack.  It turns out that
returning -1 (-EPERM) for everything was not at all helpful.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Since only a few Blackfins lack TWI, just list them in a depends
statement.
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

This patch contains the scheduled removal of i2c-i810, i2c-prosavage
and i2c-savage4.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Just like the Tyan S4882, the S4985 uses a multiplexer to give access
to all 16 memory module SPD EEPROMs. This specific i2c-nforce2-s4985
driver adds support for this. It is heavily based on the older
i2c-amd756-s4882 driver.

As more mainboards will use multiplexer chips, we will have to find a
way to support them without having to write a new specfic driver for
each. The recent changes to the i2c subsystem should help us, and the
new gpio subsystem might help, too.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

If an interrupt happens before an I2c master read/write,
complete is called on uninitialized structure.
Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>