Hi Maciej,
On Fri, May 8, 2015 at 8:14 PM, Maciej S. Szmigiero mail@maciej.szmigiero.name wrote:
I currently have audio running on this board at kernel based on vanilla 3.19 and porting required changes part-by-part to linux-next.
Changes required on vanilla 3.19 to have it working are:
AC'97 audio support needs to be added to fsl-asoc-card,
AC'97 CODEC platform device needs to be instantiated in fsl_ssi,
IPG clock needs to be enabled in fsl_ssi AC'97 mode,
so AC'97 regs can be accessed,
- Few small fixes for AC'97 mode in fsl_ssi (missing switch label
for format, missing fsl_ssi_dai_probe entry in fsl_ssi_ac97_dai, etc.).
There also is a problem with this CODEC that it seems to pull samples for S/PDIF output from time to time even if S/PDIF output is disabled.
By default this requests samples in AC'97 slots 10/11 via SLOTREQ, which in turn causes SSI to enable these slots in SACCST register and start sending half of the sound samples there.
The end result is that audio suddenly starts to play two times too fast.
Currently, I have a workaround of setting S/PDIF slot assignment in CODEC to first front pair so at least it doesn't affect playback rate.
If you like to have these changes or DT file diff then naturally I can share them, just they aren't production-quality as of now.
Good job!
Please keep me on Cc when you submit further ac97 patches / udoo dts, so that I can help testing them.
Thanks,
Fabio Estevam