2020-09-03 03:16:56

by Shengjiu Wang

Subject: [PATCH] ASoC: fsl_sai: Set SAI Channel Mode to Output Mode

Transmit data pins will output zero when slots are masked or channels
are disabled. In CHMOD TDM mode, transmit data pins are tri-stated when
slots are masked or channels are disabled. When data pins are tri-stated,
there is noise on some channels when FS clock value is high and data is
read while fsclk is transitioning from high to low.

Signed-off-by: Cosmin-Gabriel Samoila <[email protected]>
Signed-off-by: Shengjiu Wang <[email protected]>
---
sound/soc/fsl/fsl_sai.c | 12 ++++++++++--
sound/soc/fsl/fsl_sai.h | 2 ++
2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index 62c5fdb678fc..33b194a5c1dc 100644
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -486,6 +486,12 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,

val_cr4 |= FSL_SAI_CR4_FRSZ(slots);

+ /* Output Mode - data pins transmit 0 when slots are masked
+ * or channels are disabled
+ */
+ if (tx)
+ val_cr4 |= FSL_SAI_CR4_CHMOD;
+
/*
* For SAI master mode, when Tx(Rx) sync with Rx(Tx) clock, Rx(Tx) will
* generate bclk and frame clock for Tx(Rx), we should set RCR4(TCR4),
@@ -494,7 +500,8 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,

if (!sai->is_slave_mode && fsl_sai_dir_is_synced(sai, adir)) {
regmap_update_bits(sai->regmap, FSL_SAI_xCR4(!tx, ofs),
- FSL_SAI_CR4_SYWD_MASK | FSL_SAI_CR4_FRSZ_MASK,
+ FSL_SAI_CR4_SYWD_MASK | FSL_SAI_CR4_FRSZ_MASK |
+ FSL_SAI_CR4_CHMOD_MASK,
val_cr4);
regmap_update_bits(sai->regmap, FSL_SAI_xCR5(!tx, ofs),
FSL_SAI_CR5_WNW_MASK | FSL_SAI_CR5_W0W_MASK |
@@ -502,7 +509,8 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
}

regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx, ofs),
- FSL_SAI_CR4_SYWD_MASK | FSL_SAI_CR4_FRSZ_MASK,
+ FSL_SAI_CR4_SYWD_MASK | FSL_SAI_CR4_FRSZ_MASK |
+ FSL_SAI_CR4_CHMOD_MASK,
val_cr4);
regmap_update_bits(sai->regmap, FSL_SAI_xCR5(tx, ofs),
FSL_SAI_CR5_WNW_MASK | FSL_SAI_CR5_W0W_MASK |
diff --git a/sound/soc/fsl/fsl_sai.h b/sound/soc/fsl/fsl_sai.h
index 6aba7d28f5f3..19cd4e1bbff9 100644
--- a/sound/soc/fsl/fsl_sai.h
+++ b/sound/soc/fsl/fsl_sai.h
@@ -119,6 +119,8 @@
#define FSL_SAI_CR4_FRSZ_MASK (0x1f << 16)
#define FSL_SAI_CR4_SYWD(x) (((x) - 1) << 8)
#define FSL_SAI_CR4_SYWD_MASK (0x1f << 8)
+#define FSL_SAI_CR4_CHMOD BIT(5)
+#define FSL_SAI_CR4_CHMOD_MASK BIT(5)
#define FSL_SAI_CR4_MF BIT(4)
#define FSL_SAI_CR4_FSE BIT(3)
#define FSL_SAI_CR4_FSP BIT(1)
--
2.27.0

2020-09-03 03:42:08

by Nicolin Chen

Subject: Re: [PATCH] ASoC: fsl_sai: Set SAI Channel Mode to Output Mode

On Thu, Sep 03, 2020 at 11:09:15AM +0800, Shengjiu Wang wrote:
> Transmit data pins will output zero when slots are masked or channels
> are disabled. In CHMOD TDM mode, transmit data pins are tri-stated when
> slots are masked or channels are disabled. When data pins are tri-stated,
> there is noise on some channels when FS clock value is high and data is
> read while fsclk is transitioning from high to low.
>
> Signed-off-by: Cosmin-Gabriel Samoila <[email protected]>
> Signed-off-by: Shengjiu Wang <[email protected]>

Acked-by: Nicolin Chen <[email protected]>

Though one nit inline:

> ---
> sound/soc/fsl/fsl_sai.c | 12 ++++++++++--
> sound/soc/fsl/fsl_sai.h | 2 ++
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
> index 62c5fdb678fc..33b194a5c1dc 100644
> --- a/sound/soc/fsl/fsl_sai.c
> +++ b/sound/soc/fsl/fsl_sai.c
> @@ -486,6 +486,12 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
>
> val_cr4 |= FSL_SAI_CR4_FRSZ(slots);
>
> + /* Output Mode - data pins transmit 0 when slots are masked
> + * or channels are disabled
> + */

Coding style for multi-line comments. Yet, probably can simplify?

/* Set to output mode to avoid tri-stated data pins */

2020-09-03 05:40:09

by Shengjiu Wang

Subject: Re: [PATCH] ASoC: fsl_sai: Set SAI Channel Mode to Output Mode

On Thu, Sep 3, 2020 at 11:42 AM Nicolin Chen <[email protected]> wrote:
>
> On Thu, Sep 03, 2020 at 11:09:15AM +0800, Shengjiu Wang wrote:
> > Transmit data pins will output zero when slots are masked or channels
> > are disabled. In CHMOD TDM mode, transmit data pins are tri-stated when
> > slots are masked or channels are disabled. When data pins are tri-stated,
> > there is noise on some channels when FS clock value is high and data is
> > read while fsclk is transitioning from high to low.
> >
> > Signed-off-by: Cosmin-Gabriel Samoila <[email protected]>
> > Signed-off-by: Shengjiu Wang <[email protected]>
>
> Acked-by: Nicolin Chen <[email protected]>
>
> Though one nit inline:
>
> > ---
> > sound/soc/fsl/fsl_sai.c | 12 ++++++++++--
> > sound/soc/fsl/fsl_sai.h | 2 ++
> > 2 files changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
> > index 62c5fdb678fc..33b194a5c1dc 100644
> > --- a/sound/soc/fsl/fsl_sai.c
> > +++ b/sound/soc/fsl/fsl_sai.c
> > @@ -486,6 +486,12 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
> >
> > val_cr4 |= FSL_SAI_CR4_FRSZ(slots);
> >
> > + /* Output Mode - data pins transmit 0 when slots are masked
> > + * or channels are disabled
> > + */
>
> Coding style for multi-line comments. Yet, probably can simplify?
>
> /* Set to output mode to avoid tri-stated data pins */
Ok, will update in v2.

best regards
wang shengjiu