On Thu, Mar 16, 2017 at 05:41:21PM +0100, olivier moysan wrote: > Hello, > > I face two issues using wm8994 codec driver. > Below is a description of the use cases rising the problem. > I added the patches which allow to fix these issues. > These minimalist patches can be seen as a starting point for a discussion on the best > way to handle the use cases exposed. > > > - ASoC: wm8994: default master clock selection > > Use case: > CPU DAI and codec are managed through simple card. > Wolson codec wm8994 is set as slave of CPU DAI and CPU DAI feeds codec with master clock. > Master clock is derived from mclk-fs property and provided to CPU DAI and codec > through snd_soc_dai_set_sysclk API. > > Analysis: > The simple card assumes id 0 for master clock. > However wm8994 codec exposes master clock ids from 1 to 4. (MCLK1, MCLK2 ..) > > The proposal in this patch is to define a default selection regarding master clock > when id 0 is provided. > > > - ASoC: wm8994: delay aifxclk activation > > Use case: > Wolson codec wm8994 is set as slave of CPU DAI and CPU DAI feeds codec with master clock. > CPU DAI generates master clock when enabled in trigger callback. > So master clock is available only at runtime. > Master clock is not available when configuring codec through alsa controls. > > Analysis: > When we configure aifx clock while master clock is not active, related registers are not updated in wm8894 codec. > A way to go around this problem, is to delay aifxclk activation until SND_SOC_DAPM_POST_PMU DAPM stage. > The purpose of patch here is to illustrate this workaround. > > What I cannot clearly figure out, is how this may impact other uses of wm8894 codec. > I try to know if it's worth investigating further in this direction or if it will not be applicable. > If not applicable, what maybe the other options ? > > regards > olivier Would be good to CC patches@xxxxxxxxxxxxxxxxxxxxxxxxxxx on the next version of these patches as well, higher chance someone here will notice and have a look over them. Thanks, Charles _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
