PMBUS_ON_OFF_CONFIG
rc = i2c_smbus_read_byte_data(psu->client, PMBUS_ON_OFF_CONFIG);
rc = i2c_smbus_write_byte_data(psu->client, PMBUS_ON_OFF_CONFIG, data);
ret = i2c_smbus_read_byte_data(psu->client, PMBUS_ON_OFF_CONFIG);
ret = i2c_smbus_read_byte_data(client, PMBUS_ON_OFF_CONFIG);
PMBUS_ON_OFF_CONFIG);
return pmbus_update_byte_data(client, page, PMBUS_ON_OFF_CONFIG,