The current internal API for TDM is very poor, I don't think we want to expose that 1 to 1 to the devicetree. Since this means we'd have to support that forever. The first thing is that the semantics of snd_soc_dai_set_tdm_slot() are very unclear. E.g. some drivers use a zero bit for a active slot, some drivers use a 1 bit for a active
Yes, and if we do end up using masks we need to nail down what's going on in the DT.
Yes, certainly.
slot. The second thing is that we are not able to specify which channel should be mapped to which slot. You can merely specify from/to which slots the CODEC should read/write and then it is up to the driver to guess which channel should go to which slot. In my opinion a binding that allows to specify a explicit mapping of which channel goes to which slot would be much better.
It'd certainly be good to be able to do that, though having a default would make life easier.
@Lars, @Mark,
Yes, then will that means that we can just end up parsing masks from DT and the masks will be generated by the driver specified dai->driver->ops->of_xlate_tdm_slot_mask(slots, &tx_mask, &rx_mask) callback or one default snd_soc_of_xlate_tdm_slot_mask(slots, &tx_mask, &rx_mask), and the 'slots' is the number of the slot parsed from the DT node ?
Or other better ways ?
Thanks,
-- Best Regards, Xiubo
Also those are four different settings. In my opinion they should not be expressed in one property, but rather in four. E.g. specifying a tx_mask for a rx only device does not make much sense.
That makes sense.