sound: oxygen: automatically restore overwritten EEPROM

If the EEPROM was partially overwritten (which seems to happen before the OS is
booted), restore its entire contents by deducing it from the remaining
information.

This does not have any effect on the Linux driver, which works even with
incomplete information in the EEPROM, but it makes other drivers work again.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/oxygen/oxygen_io.c

@@ -269,3 +269,19 @@ u16 oxygen_read_eeprom(struct oxygen *chip, unsigned int index)
 	}
 	return oxygen_read16(chip, OXYGEN_EEPROM_DATA);
 }
+
+void oxygen_write_eeprom(struct oxygen *chip, unsigned int index, u16 value)
+{
+	unsigned int timeout;
+
+	oxygen_write16(chip, OXYGEN_EEPROM_DATA, value);
+	oxygen_write8(chip, OXYGEN_EEPROM_CONTROL,
+		      index | OXYGEN_EEPROM_DIR_WRITE);
+	for (timeout = 0; timeout < 10; ++timeout) {
+		msleep(1);
+		if (!(oxygen_read8(chip, OXYGEN_EEPROM_STATUS)
+		      & OXYGEN_EEPROM_BUSY))
+			return;
+	}
+	snd_printk(KERN_ERR "EEPROM write timeout\n");
+}