+ * read() - Read multiple 8-bit registers
+ *
+ * @dev: Device to read from
+ * @reg: First register to read
+ * @buf: Output buffer
+ * @len: Number of registers to read
+ * @return 0 if OK, -ve on error
+ */
+ int (*read)(struct udevice *dev, unsigned int reg,
+ u8 *buf, unsigned int len);
+
+ /**
+ * write() - Write multiple 8-bit registers
+ *
+ * @dev: Device to write to
+ * @reg: First register to write
+ * @buf: Input buffer
+ * @len: Number of registers to write
+ * @return 0 if OK, -ve on error
+ */
+ int (*write)(struct udevice *dev, unsigned int reg,
+ const u8 *buf, unsigned int len);
+
+ /**