[alsa-devel] [PATCH V2] ASoC: tlv320aic3x: Fix codec pll configure bug

[Hebbar, Gururaja]

On Tue, Jun 26, 2012 at 14:31:42, Prchal Jiří wrote:
> Hi Gururaja,
> shouldn't be better to use:
> 
> snd_soc_update_bits(codec, AIC3X_PLL_PROGA_REG, PLLP_MASK, pll_p);
> 
> instead of "read mask write" ?

Sure will resend the patch. Thanks for the review

> Even at this place you don't need to keep rest of register (PLL_Q and PLL_enable), so yust writing is OK.
> 
> snd_soc_write(codec, AIC3X_PLL_PROGA_REG, pll_p << PLLP_SHIFT);
> 

> Dne 26.6.2012 08:03, Hebbar, Gururaja napsal(a):
> > In sound/soc/codecs/tlv320aic3x.c
> >
> >          data = snd_soc_read(codec, AIC3X_PLL_PROGA_REG);
> >          snd_soc_write(codec, AIC3X_PLL_PROGA_REG,
> >                        data | (pll_p<<  PLLP_SHIFT));
> >
> > In the above code, pll-p value is OR'ed with previous value without
> > clearing it. Bug is not seen if pll-p value doesn't change across
> > Sampling frequency.
> >
> > However on some platforms (like AM335x EVM-SK), pll-p may have different
> > values across different sampling frequencies. In such case, above code
> > configures the pll with a wrong value.
> > Because of this bug, when a audio stream is played with pll value
> > different from previous stream, audio is heard as differently.
> >
> > Signed-off-by: Hebbar, Gururaja<gururaja.hebbar at ti.com>
> > ---
> > chnages in V2:
> > 	modify subject to indicate ASOC and codec as tlv320aic3x
> >
> >   sound/soc/codecs/tlv320aic3x.c |    2 +-
> >   sound/soc/codecs/tlv320aic3x.h |    1 +
> >   2 files changed, 2 insertions(+), 1 deletions(-)
> >
> > diff --git a/sound/soc/codecs/tlv320aic3x.c b/sound/soc/codecs/tlv320aic3x.c
> > index d0dbac1..8c1977b 100644
> > --- a/sound/soc/codecs/tlv320aic3x.c
> > +++ b/sound/soc/codecs/tlv320aic3x.c
> > @@ -963,7 +963,7 @@ static int aic3x_hw_params(struct snd_pcm_substream *substream,
> >   	}
> >
> >   found:
> > -	data = snd_soc_read(codec, AIC3X_PLL_PROGA_REG);
> > +	data = snd_soc_read(codec, AIC3X_PLL_PROGA_REG)&  ~PLLP_MASK;
> >   	snd_soc_write(codec, AIC3X_PLL_PROGA_REG,
> >   		      data | (pll_p<<  PLLP_SHIFT));
> >   	snd_soc_write(codec, AIC3X_OVRF_STATUS_AND_PLLR_REG,
> > diff --git a/sound/soc/codecs/tlv320aic3x.h b/sound/soc/codecs/tlv320aic3x.h
> > index 06a1978..16d9999 100644
> > --- a/sound/soc/codecs/tlv320aic3x.h
> > +++ b/sound/soc/codecs/tlv320aic3x.h
> > @@ -166,6 +166,7 @@
> >
> >   /* PLL registers bitfields */
> >   #define PLLP_SHIFT		0
> > +#define PLLP_MASK		7
> >   #define PLLQ_SHIFT		3
> >   #define PLLR_SHIFT		0
> >   #define PLLJ_SHIFT		2
> 
> 


Regards, 
Gururaja