the SGTL can switch Line-In to HP-OUT using "codec bypass". We want to use this mode.
Our Problem: The SGTL does not switch the line-in DC-bias voltage on, if this mode is selected, which sounds horrible. If we read from the line-in using the ADC prior to switching to this mode, the DC-bias is on. So there is a workaround, but it isnt pretty.
This looks like an error of some sorts in the linux driver.
According to the datasheet, there is no setting switch a DC-Bias to the line-in. On the other hand, the driver seems to toggle some "reserved" bits.
How can we switch the DC-Bias on, without using the ADC first?