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: Jean Delvare <khali@linux-fr.org>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Konstantin Lazarev <klazarev@sbcglobal.net>
This allows bin_attr->read,write,mmap callbacks to check file specific data
(such as inode owner) as part of any privilege validation.
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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: Kevin Hilman <khilman@deeprootsystems.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus 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: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
