i2c: New-style EEPROM driver using device IDs

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>

drivers/i2c/chips/Kconfig

@@ -14,6 +14,32 @@ config DS1682
 	  This driver can also be built as a module.  If so, the module
 	  will be called ds1682.
 
+config AT24
+	tristate "EEPROMs from most vendors"
+	depends on SYSFS && EXPERIMENTAL
+	help
+	  Enable this driver to get read/write support to most I2C EEPROMs,
+	  after you configure the driver to know about each EEPROM on
+	  your target board.  Use these generic chip names, instead of
+	  vendor-specific ones like at24c64 or 24lc02:
+
+	     24c00, 24c01, 24c02, spd (readonly 24c02), 24c04, 24c08,
+	     24c16, 24c32, 24c64, 24c128, 24c256, 24c512, 24c1024
+
+	  Unless you like data loss puzzles, always be sure that any chip
+	  you configure as a 24c32 (32 kbit) or larger is NOT really a
+	  24c16 (16 kbit) or smaller, and vice versa. Marking the chip
+	  as read-only won't help recover from this. Also, if your chip
+	  has any software write-protect mechanism you may want to review the
+	  code to make sure this driver won't turn it on by accident.
+
+	  If you use this with an SMBus adapter instead of an I2C adapter,
+	  full functionality is not available.  Only smaller devices are
+	  supported (24c16 and below, max 4 kByte).
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called at24.
+
 config SENSORS_EEPROM
 	tristate "EEPROM reader"
 	depends on EXPERIMENTAL

drivers/i2c/chips/Makefile

@@ -10,6 +10,7 @@
 #
 
 obj-$(CONFIG_DS1682)		+= ds1682.o
+obj-$(CONFIG_AT24)		+= at24.o
 obj-$(CONFIG_SENSORS_EEPROM)	+= eeprom.o
 obj-$(CONFIG_SENSORS_MAX6875)	+= max6875.o
 obj-$(CONFIG_SENSORS_PCA9539)	+= pca9539.o