On Mon, Jun 29, 2015 at 10:44:12AM +0100, Charles Keepax wrote: > On Fri, Jun 26, 2015 at 07:09:22PM +0800, Zidan Wang wrote: > > When using snd_soc_dai_set_pll to set pll in machine driver, we > > should set pll in and pll out freq and ensure 5 < PLLN < 13, > > otherwise set pll will be failed. In order to support more > > formats and sample rates for a certain MCLK, if snd_soc_dai_set_pll > > failed, it will calculate a available pll out freq and set the pll > > again. > > > > Signed-off-by: Zidan Wang <zidan.w...@freescale.com> > > --- > > I think this need a little more explaination on how this is > expected to work. From looking at the code what it looks like > what happens is you can set a PLL frequency through set_pll but > then if that frequency doesn't support the sample rate requested > through hw_params it will be changed. This makes me a little > nervous, as something explicitly requested is being overwritten > automatically. > >From RM, we should ensure 5 < PLLN < 13. When i using snd_soc_dai_set_pll to set pll frequency, it's hard for me to get a common pll out frequency. Sometimes, when codec MCLK or sample rate changed, the pll out frequency also should be changed, otherwise set_pll function will be failed.
I made it to auto select pll frequency when snd_soc_dai_set_pll failed, so that it can support more sample rate, and don't need to set different pll out frequency for different sample rate and different MCLK. > Would it perhaps be better to allow the auto selection of the > PLL frequency only when things haven't been manually set, or > provide some setting that indicates auto mode? > > Thanks, > Charles -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
