[PATCH v3] ASoC: fsl_ssi: Fix bclk calculation for mono channel

[PATCH v3] ASoC: fsl_ssi: Fix bclk calculation for mono channel

[Shengjiu Wang]

For mono channel, SSI will switch to Normal mode.

In Normal mode and Network mode, the Word Length Control bits
control the word length divider in clock generator, which is
different with I2S Master mode (the word length is fixed to
32bit), it should be the value of params_width(hw_params).

The condition "slots == 2" is not good for I2S Master mode,
because for Network mode and Normal mode, the slots can also
be 2. Then we need to use (ssi->i2s_net & SSI_SCR_I2S_MODE_MASK)
to check if it is I2S Master mode.

So we refine the formula for mono channel, otherwise there
will be sound issue for S24_LE.

Fixes: b0a7043d5c2c ("ASoC: fsl_ssi: Caculate bit clock rate using slot number and width")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
---
changes in v3
- update according to Nicolin's comments

changes in v2
- refine patch for Network mode and Normal mode.

 sound/soc/fsl/fsl_ssi.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index bad89b0d129e..1a2fa7f18142 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -678,8 +678,9 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream,
 	struct regmap *regs = ssi->regs;
 	u32 pm = 999, div2, psr, stccr, mask, afreq, factor, i;
 	unsigned long clkrate, baudrate, tmprate;
-	unsigned int slots = params_channels(hw_params);
-	unsigned int slot_width = 32;
+	unsigned int channels = params_channels(hw_params);
+	unsigned int slot_width = params_width(hw_params);
+	unsigned int slots = 2;
 	u64 sub, savesub = 100000;
 	unsigned int freq;
 	bool baudclk_is_used;
@@ -688,10 +689,14 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream,
 	/* Override slots and slot_width if being specifically set... */
 	if (ssi->slots)
 		slots = ssi->slots;
-	/* ...but keep 32 bits if slots is 2 -- I2S Master mode */
-	if (ssi->slot_width && slots != 2)
+	if (ssi->slot_width)
 		slot_width = ssi->slot_width;
 
+	/* ...but force 32 bits for stereo audio using I2S Master Mode */
+	if (channels == 2 &&
+	    (ssi->i2s_net & SSI_SCR_I2S_MODE_MASK) == SSI_SCR_I2S_MODE_MASTER)
+		slot_width = 32;
+
 	/* Generate bit clock based on the slot number and slot width */
 	freq = slots * slot_width * params_rate(hw_params);
 
-- 
2.21.0

Re: [PATCH v3] ASoC: fsl_ssi: Fix bclk calculation for mono channel

[Nicolin Chen]

On Tue, Jun 16, 2020 at 10:53:48AM +0800, Shengjiu Wang wrote:
> For mono channel, SSI will switch to Normal mode.
> 
> In Normal mode and Network mode, the Word Length Control bits
> control the word length divider in clock generator, which is
> different with I2S Master mode (the word length is fixed to
> 32bit), it should be the value of params_width(hw_params).
> 
> The condition "slots == 2" is not good for I2S Master mode,
> because for Network mode and Normal mode, the slots can also
> be 2. Then we need to use (ssi->i2s_net & SSI_SCR_I2S_MODE_MASK)
> to check if it is I2S Master mode.
> 
> So we refine the formula for mono channel, otherwise there
> will be sound issue for S24_LE.
> 
> Fixes: b0a7043d5c2c ("ASoC: fsl_ssi: Caculate bit clock rate using slot number and width")
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>

Reviewed-by: Nicolin Chen <nicoleotsuka@gmail.com>

Re: [PATCH v3] ASoC: fsl_ssi: Fix bclk calculation for mono channel

[Mark Brown]

On Tue, 16 Jun 2020 10:53:48 +0800, Shengjiu Wang wrote:
> For mono channel, SSI will switch to Normal mode.
> 
> In Normal mode and Network mode, the Word Length Control bits
> control the word length divider in clock generator, which is
> different with I2S Master mode (the word length is fixed to
> 32bit), it should be the value of params_width(hw_params).
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: fsl_ssi: Fix bclk calculation for mono channel
      commit: ed1220df6e666500ebf58c4f2fccc681941646fb

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark