i have a wm8988 connected to imx6qp, kernel 4.1.15.
Linux has the wm8988 driver, but machine driver was missing and i am setting up a simple one, based on
similar ASoC machine drivers.
I am actually trying to set imx6qp as i2s master, and codec device as slave.
Card is detected properly and registered, if i try some alsa "speaker-test", i am observing (by scope)
- i2c transfers works fine, tested writing and reading from codec rtegisters
- i2s BCLK, LRframe clock and samples, all driven from cpu
- i see also sysclk, that is sent from CPU CKO output as 24000000,
- i see no output at all from any of the 4 codec analogues outputs. Tried do change mixer settings, aplay, paplay, always
nothing in the outputs.
So my questions actually are:
1) what should be the reasons in selecting the codec mode as i2s master or slave ?
2) Is it ok to be interfaced to the codec with imx6qp as the i2s master ?
3) do you have any knowledge of a similar imx machine driver for a similar codec/scenario ?