Re: [PATCH 1/2] ASoC: Fix mpc5200-psc-ac97 to ensure the data ready bit is cleared

[Jon Smirl <jonsmirl@gmail.com>]

On Thu, Jul 2, 2009 at 1:57 PM, Grant Likely<grant.likely@secretlab.ca> wro=
te:
> From: Grant Likely <grant.likely@secretlab.ca>
>
> When doing register reads, it is possible for there to be a stale
> data ready bit set which will cause subsequent reads to return
> prematurely with incorrect data. =A0This patch fixes the issues by
> ensuring stale data is cleared before starting another transaction.
>
> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Acked-by: Jon Smirl <jonsmirl@gmail.com>

> ---
>
> =A0sound/soc/fsl/mpc5200_psc_ac97.c | =A0 =A04 ++++
> =A01 files changed, 4 insertions(+), 0 deletions(-)
>
>
> diff --git a/sound/soc/fsl/mpc5200_psc_ac97.c b/sound/soc/fsl/mpc5200_psc=
_ac97.c
> index 794a247..9b8503f 100644
> --- a/sound/soc/fsl/mpc5200_psc_ac97.c
> +++ b/sound/soc/fsl/mpc5200_psc_ac97.c
> @@ -41,6 +41,10 @@ static unsigned short psc_ac97_read(struct snd_ac97 *a=
c97, unsigned short reg)
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0pr_err("timeout on ac97 bus (rdy)\n");
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0return -ENODEV;
> =A0 =A0 =A0 =A0}
> +
> + =A0 =A0 =A0 /* Force clear the data valid bit */
> + =A0 =A0 =A0 in_be32(&psc_dma->psc_regs->ac97_data);
> +
> =A0 =A0 =A0 =A0/* Send the read */
> =A0 =A0 =A0 =A0out_be32(&psc_dma->psc_regs->ac97_cmd, (1<<31) | ((reg & 0=
x7f) << 24));
>
>
>



--=20
Jon Smirl
jonsmirl@gmail.com