Add a mechanism to let new-style i2c drivers optionally autodetect
devices they would support on selected buses and ask i2c-core to
instantiate them. This is a replacement for legacy i2c drivers, much
cleaner.

Where drivers had to implement both a legacy i2c_driver and a
new-style i2c_driver so far, this mechanism makes it possible to get
rid of the legacy i2c_driver and implement both enumerated and
detected device support with just one (new-style) i2c_driver.

Here is a quick conversion guide for these drivers, step by step:

* Delete the legacy driver definition, registration and removal.
  Delete the attach_adapter and detach_client methods of the legacy
  driver.

* Change the prototype of the legacy detect function from
    static int foo_detect(struct i2c_adapter *adapter, int address, int kind);
  to
    static int foo_detect(struct i2c_client *client, int kind,
    			  struct i2c_board_info *info);

* Set the new-style driver detect callback to this new function, and
  set its address_data to &addr_data (addr_data is generally provided
  by I2C_CLIENT_INSMOD.)

* Add the appropriate class to the new-style driver. This is
  typically the class the legacy attach_adapter method was checking
  for. Class checking is now mandatory (done by i2c-core.) See
  <linux/i2c.h> for the list of available classes.

* Remove the i2c_client allocation and freeing from the detect
  function. A pre-allocated client is now handed to you by i2c-core,
  and is freed automatically.

* Make the detect function fill the type field of the i2c_board_info
  structure it was passed as a parameter, and return 0, on success. If
  the detection fails, return -ENODEV.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

We call adapter->client_register for both legacy and new-style i2c
devices, however we only call adapter->client_unregister for legacy
drivers. This doesn't make much sense. Usually, drivers will undo
in client_unregister what they did in client_register, so we should
call neither or both for every given i2c device.

In order to ease the transition from legacy to new-style devices, it
seems preferable to actually call both.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: David Brownell <david-b@pacbell.net>

Clean up old i2c chip drivers:
* Name the i2c_client "client" instead of "new_client".
* Drop useless initializations to 0.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

This patch completes the conversion of the IBM IIC driver to an
of-platform driver.

It removes the index from the IBM IIC driver and makes it an unnumbered
driver. It then calls of_register_i2c_devices to properly register all
the child nodes in the DTS.
Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Add a new-style driver for most I2C EEPROMs, giving sysfs read/write
access to their data. Tested with various chips and clock rates.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Export the root of the i2c bus so that PowerPC device tree code can
iterate over devices on the i2c bus.
Signed-off-by: Jon Smirl <jonsmirl@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Fix driver power management:
- suspend the PSC while driver is idle.
- move PSC init/deinit to separate functions, as PSC must be
  initialized/shutdown on resume/suspend.
Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Implementing detach_client is optional, so there is no point in
an empty implementation.

Likewise, i2c driver IDs are optional, and we don't need one.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Signed-off-by: Jean Delvare <khali@linux-fr.org>

Check for ACPI resource conflicts in i2c bus drivers. I've included
all recent SMBus master drivers for PC hardware.

I've voluntarily left out:
* Drivers that don't run on PCs: they can't conflict with ACPI.
* Bit-banged bus device drivers: it's very unlikely that ACPI would
  deal with such buses.
Signed-off-by: Jean Delvare <jdelvare@suse.de>

Basic PM support: reinit the core on resume, disable it on suspend.
Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

 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>