memory_accessor: implement the new memory_accessor interface for I2C EEPROM

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>
diff --git a/include/linux/i2c/at24.h b/include/linux/i2c/at24.h
index f6edd52..8ace930 100644
--- a/include/linux/i2c/at24.h
+++ b/include/linux/i2c/at24.h
@@ -2,6 +2,7 @@
 #define _LINUX_AT24_H
 
 #include <linux/types.h>
+#include <linux/memory.h>
 
 /*
  * As seen through Linux I2C, differences between the most common types of I2C
@@ -23,6 +24,9 @@
 #define AT24_FLAG_READONLY	0x40	/* sysfs-entry will be read-only */
 #define AT24_FLAG_IRUGO		0x20	/* sysfs-entry will be world-readable */
 #define AT24_FLAG_TAKE8ADDR	0x10	/* take always 8 addresses (24c00) */
+
+	void		(*setup)(struct memory_accessor *, void *context);
+	void		*context;
 };
 
 #endif /* _LINUX_AT24_H */