Increase the portability of the at24 driver by letting it read from
EEPROM chips connected to cheap SMBus controllers that support neither
raw I2C messages nor even I2C block reads. All SMBus controllers
should support either word reads or byte reads, so read support
becomes universal, much like with the legacy "eeprom" driver.

Obviously, this only works with EEPROM chips up to AT24C16, that use
8-bit offset addressing. 16-bit offset addressing is almost impossible
to support on SMBus controllers.

I did not add universal support for writes, as I had no immediate need
for this, but it could be added later if needed (with the same
performance issue as byte and word reads have, of course.)
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Reviewed-by: NWolfram Sang <w.sang@pengutronix.de>
Cc: Konstantin Lazarev <klazarev@sbcglobal.net>

Commit 6992f533 introduced this requirement.
Reported-by: NAlbrecht Dress <albrecht.dress@arcor.de>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Writes may take some time on EEPROMs, so for consecutive writes, we already
have a loop waiting for the EEPROM to become ready. Use such a loop for reads,
too, in case somebody wants to immediately read after a write. Detailed bug
report and test case can be found here:

http://article.gmane.org/gmane.linux.drivers.i2c/4660Reported-by: NAleksandar Ivanov <ivanov.aleks@gmail.com>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Tested-by: NAleksandar Ivanov <ivanov.aleks@gmail.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

| drivers/misc/eeprom/at24.c:508: warning: assignment from incompatible pointer type
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In the case of at24, the platform code registers a 'setup' callback with
the at24_platform_data.  When the at24 driver detects an EEPROM, it fills
out the read and write functions of the memory_accessor and calls the
setup callback passing the memory_accessor struct.  The platform code can
then use the read/write functions in the memory_accessor struct for
reading and writing the EEPROM.
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As drivers/i2c/chips is going to go away, move the driver to
drivers/misc/eeprom. Other eeprom drivers may be moved here later, too.
Update Kconfig text to specify this driver as I2C.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Tejun's commit 7b595756 made sysfs
attribute->owner unnecessary.  But the field was left in the structure to
ease the merge.  It's been over a year since that change and it is now
time to start killing attribute->owner along with its users - one arch at
a time!

This patch is attempt #1 to get rid of attribute->owner only for
CONFIG_X86_64 or CONFIG_X86_32 .  We will deal with other arches later on
as and when possible - avr32 will be the next since that is something I
can test.  Compile (make allyesconfig / make allmodconfig / custom config)
and boot tested.

akpm: the idea is that we put the declaration of sttribute.owner inside
`#ifndef CONFIG_X86'.  But that proved to be too ambitious for now because
new usages kept on turning up in subsystem trees.

[akpm: remove the ifdef for now]
Signed-off-by: NParag Warudkar <parag.lkml@gmail.com>
Cc: Greg KH <greg@kroah.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix various printk format strings where %zd was passed a size_t;
those should be %zu instead.  (Courtesy of a version of GCC which
warns when these details are wrong.)
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NJean 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: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NJean Delvare <khali@linux-fr.org>