unsigned int index, u16 data, u16 mask);
 
 void oxygen_write_spi(struct oxygen *chip, u8 control, unsigned int data);
+void oxygen_write_i2c(struct oxygen *chip, u8 device, u8 map, u8 data);
 
 static inline void oxygen_set_bits8(struct oxygen *chip,
                                    unsigned int reg, u8 value)
 
                --count;
        }
 
-       spin_lock_irq(&chip->reg_lock);
        oxygen_write8(chip, OXYGEN_SPI_DATA1, data);
        oxygen_write8(chip, OXYGEN_SPI_DATA2, data >> 8);
        if (control & OXYGEN_SPI_DATA_LENGTH_3)
                oxygen_write8(chip, OXYGEN_SPI_DATA3, data >> 16);
        oxygen_write8(chip, OXYGEN_SPI_CONTROL, control);
-       spin_unlock_irq(&chip->reg_lock);
 }
 EXPORT_SYMBOL(oxygen_write_spi);
+
+void oxygen_write_i2c(struct oxygen *chip, u8 device, u8 map, u8 data)
+{
+       unsigned long timeout;
+
+       /* should not need more than about 300 us */
+       timeout = jiffies + msecs_to_jiffies(1);
+       do {
+               if (!(oxygen_read16(chip, OXYGEN_2WIRE_BUS_STATUS)
+                     & OXYGEN_2WIRE_BUSY))
+                       break;
+               udelay(1);
+               cond_resched();
+       } while (time_after_eq(timeout, jiffies));
+
+       oxygen_write8(chip, OXYGEN_2WIRE_MAP, map);
+       oxygen_write8(chip, OXYGEN_2WIRE_DATA, data);
+       oxygen_write8(chip, OXYGEN_2WIRE_CONTROL,
+                     device | OXYGEN_2WIRE_DIR_WRITE);
+}
+EXPORT_SYMBOL(oxygen_write_i2c);