The datasheet and the errata say the SGTL5000 should be connected to an external VDDD supply.
The linux driver (both mainline and the one in the QorIQ-SDK 1.7) try to use it. But with codec revision >= 0x11 it falls back to internal LDO.
It seems that the sgtl5000 driver did this from the first version integrated into linux mainline. But I could not find any documentation why this should be done (starting from this specific revision).
This topic seems to be referred by others too: e.g. Re: SGTL5000 hangs I2C bus after reset
So my questions:
- For which reason the internal LDO instead of external VDDD should be used on revisions >=0x11?
- What is the correct codec configuration regarding VDDD?
- Are there any driver patches available? Especially regarding QorIQ-SDK. Maybe I can also backport them from mainline.