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>

include/linux/i2c/at24.h

@@ -0,0 +1,28 @@
+#ifndef _LINUX_AT24_H
+#define _LINUX_AT24_H
+
+#include <linux/types.h>
+
+/*
+ * As seen through Linux I2C, differences between the most common types of I2C
+ * memory include:
+ * - How much memory is available (usually specified in bit)?
+ * - What write page size does it support?
+ * - Special flags (16 bit addresses, read_only, world readable...)?
+ *
+ * If you set up a custom eeprom type, please double-check the parameters.
+ * Especially page_size needs extra care, as you risk data loss if your value
+ * is bigger than what the chip actually supports!
+ */
+
+struct at24_platform_data {
+	u32		byte_len;		/* size (sum of all addr) */
+	u16		page_size;		/* for writes */
+	u8		flags;
+#define AT24_FLAG_ADDR16	0x80	/* address pointer is 16 bit */
+#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) */
+};
+
+#endif /* _LINUX_AT24_H */