On Fri, Nov 27, 2015 at 12:26:27PM +0000, Mark Brown wrote: > On Thu, Nov 26, 2015 at 02:03:20PM +0000, Charles Keepax wrote: > > When switching between two clock sources using the FLL freerun to smooth > > the transition we should wait 32uS after putting the FLL into freerun > > before we proceed. In practice we appear to be getting enough delay from > > the surrounding code, but better to make it explicit. > > You'll almost certainly get 32us from just setting up the I/O and > also... > > > +++ b/sound/soc/codecs/arizona.c > > @@ -2215,6 +2215,7 @@ static int arizona_enable_fll(struct arizona_fll *fll) > > regmap_update_bits_async(fll->arizona->regmap, fll->base + 1, > > ARIZONA_FLL1_FREERUN, > > ARIZONA_FLL1_FREERUN); > > + udelay(32); > > ...this won't do what you say it will - the I/O is asynchronous so what > this will do is add a delay immediately after scheduling the I/O while > the I/O is at best in progress and most likely before it is ever begun. > You'd need to make the I/O synchronous to actually introduce the delay. Oops.. missed that, apologies I will respin. Thanks, Charles _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
