On Thu, Sep 17, 2009 at 10:11 PM, Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > On Thu, Sep 17, 2009 at 09:26:28PM +0900, jassi brar wrote: > >> > > + /* Currently, WM8580 driver doesn't support PLL-out rates >> > > + * other than those mentioned in Table-52 Page-58 of WM8580A > >> That very manual. And i don't say the WM8580 doesn't support, I said >> the WM8580 driver doesn't support: which can be verified looking at the >> CODEC driver. > > Your comment says that only the output frequencies in table 52 are > supported. Could you please provide more specific references to where > this is done in the driver? I think you're confusing the fact that the > example table lists most of the common audio frequencies with what the > driver supports here. Let me be precise. With this machine driver and the WM8580 CODEC driver from origin/for-2.6.32 if we do any of the following:- snd_soc_dai_set_pll(codec_dai, WM8580_PLLA, 12000000, 8000*256); snd_soc_dai_set_pll(codec_dai, WM8580_PLLA, 12000000, 11025*256); snd_soc_dai_set_pll(codec_dai, WM8580_PLLA, 12000000, 64000*256); we get the error: "wm8580: Unable to scale output frequency" >> Theoretically all output clocks are possible but usually the PLL coefficients >> have limits on their value and thus final output. WM8580 driver too seems >> to enforce that. >> Though, you wud know better of WM8580. > > So what you're actually saying is that 256fs doesn't give us the option > of an an in-range Fvco for the FLL at those frequencies (which is the > check I think you're talking about here)? That's a limitation of the > chip. > Certainly, the comment is not accurate - the contents of table 52 aren't > relevant here, the driver is calculating what it can do dynamically so > the restrictions are a combination of the limits on Fvco and the pre and > post scaling dividers available. Of course, there just might be a set of values for PLL coeffs that output 256fs for 8000, 11025 and 64000. If that set is within acceptable range of of the chip then it's just a matter of driver upgrade otherwise its a limitation of the chip. You wud know which case is it. I apologize if my inappropriate selection of expression bothered you. In future, please feel free to suggest modification of any comment in the code. Regards. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
