On Mon, Apr 3, 2017 at 4:34 PM, Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > On Mon, Apr 03, 2017 at 04:16:23PM +0300, Daniel Baluta wrote: >> On Thu, Jan 15, 2015 at 3:34 PM, Zidan Wang <b50113@xxxxxxxxxxxxx> wrote: >> > On Wed, Jan 14, 2015 at 07:27:03PM +0000, Mark Brown wrote: >> >> On Wed, Jan 07, 2015 at 03:31:45PM +0800, Zidan Wang wrote: >> > I found it can't generate bclk for S20_3LE data format. >> > >> > For 2 channel S20_3LE data format: >> > >> > bclk = fs * 20 * 2 >> > Sysclk = BCLKDIV * bclk = BCLKDIV * fs * 40 >> > Sysclk = DACDIV * fs * 256 >> > >> > BCLKDIV/DACDIV = 256/40 = 32/5 >> > >> > But BCLKDIV/DACDIV can't be 32/5. So I want to support tdm slot. >> > >> > bclk = fs * slot_width * slots * channal. >> > >> > Do you think it make sense, or any other ideas? >> >> Reviving this question after two years :). >> >> After "ASoC: codec: wm8960: Relax bit clock computation" patch >> >> https://patchwork.kernel.org/patch/9636769/ >> >> we can now support S20_3LE for round rates like 8000, 16000, >> 32000 and 48000. >> >> But not for 11025, 22050, 441000. Do you think it's worth exploring >> "tdm slot" idea? I don't know exactly what it implies. >> >> Another idea, is to completely remove support for S20_3LE since it >> is not trivial to derive bitclk from sysclk. >> >> What do you guys think? > > Does this problem still remain after the relaxed clock > computation? The maths you quote depends on the derived BCLK > being exactly the correct speed for the audio, that is no longer > the case anymore. > > I would have thought the patch would cover both situations, as in > if we can produce a suitable LRCLK, then we just pick a BCLK we That! The problem for remaining rates is that we cannot derive the LRCLK <snip> + for (j = 0; j < ARRAY_SIZE(dac_divs); ++j) { + if (sysclk != dac_divs[j] * lrclk) + continue; </snip> > can produce that is higher than we need. I don't see why that > depends on things being a 48k based rate there. Am I missing > something? _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
