[PATCH v3] ASoC: fsl_asrc: Add an option to select internal ratio mode

[PATCH v3] ASoC: fsl_asrc: Add an option to select internal ratio mode

[Shengjiu Wang]

The ASRC not only supports ideal ratio mode, but also supports
internal ratio mode.

For internal rato mode, the rate of clock source should be divided
with no remainder by sample rate, otherwise there is sound
distortion.

Add function fsl_asrc_select_clk() to find proper clock source for
internal ratio mode, if the clock source is available then internal
ratio mode will be selected.

With change, the ideal ratio mode is not the only option for user.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
---
changes in v3
- convert fsl_asrc_select_clk to void type

changes in v2
- update according to Nicolin's comments

 sound/soc/fsl/fsl_asrc.c | 46 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c
index 95f6a9617b0b..462ce9f9ab48 100644
--- a/sound/soc/fsl/fsl_asrc.c
+++ b/sound/soc/fsl/fsl_asrc.c
@@ -582,11 +582,51 @@ static int fsl_asrc_dai_startup(struct snd_pcm_substream *substream,
 			SNDRV_PCM_HW_PARAM_RATE, &fsl_asrc_rate_constraints);
 }
 
+/* Select proper clock source for internal ratio mode */
+static void fsl_asrc_select_clk(struct fsl_asrc_priv *asrc_priv,
+				struct fsl_asrc_pair *pair,
+				int in_rate,
+				int out_rate)
+{
+	struct fsl_asrc_pair_priv *pair_priv = pair->private;
+	struct asrc_config *config = pair_priv->config;
+	int rate[2], select_clk[2]; /* Array size 2 means IN and OUT */
+	int clk_rate, clk_index;
+	int i = 0, j = 0;
+
+	rate[IN] = in_rate;
+	rate[OUT] = out_rate;
+
+	/* Select proper clock source for internal ratio mode */
+	for (j = 0; j < 2; j++) {
+		for (i = 0; i < ASRC_CLK_MAP_LEN; i++) {
+			clk_index = asrc_priv->clk_map[j][i];
+			clk_rate = clk_get_rate(asrc_priv->asrck_clk[clk_index]);
+			/* Only match a perfect clock source with no remainder */
+			if (clk_rate != 0 && (clk_rate / rate[j]) <= 1024 &&
+			    (clk_rate % rate[j]) == 0)
+				break;
+		}
+
+		select_clk[j] = i;
+	}
+
+	/* Switch to ideal ratio mode if there is no proper clock source */
+	if (select_clk[IN] == ASRC_CLK_MAP_LEN || select_clk[OUT] == ASRC_CLK_MAP_LEN) {
+		select_clk[IN] = INCLK_NONE;
+		select_clk[OUT] = OUTCLK_ASRCK1_CLK;
+	}
+
+	config->inclk = select_clk[IN];
+	config->outclk = select_clk[OUT];
+}
+
 static int fsl_asrc_dai_hw_params(struct snd_pcm_substream *substream,
 				  struct snd_pcm_hw_params *params,
 				  struct snd_soc_dai *dai)
 {
 	struct fsl_asrc *asrc = snd_soc_dai_get_drvdata(dai);
+	struct fsl_asrc_priv *asrc_priv = asrc->private;
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct fsl_asrc_pair *pair = runtime->private_data;
 	struct fsl_asrc_pair_priv *pair_priv = pair->private;
@@ -605,8 +645,6 @@ static int fsl_asrc_dai_hw_params(struct snd_pcm_substream *substream,
 
 	config.pair = pair->index;
 	config.channel_num = channels;
-	config.inclk = INCLK_NONE;
-	config.outclk = OUTCLK_ASRCK1_CLK;
 
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 		config.input_format   = params_format(params);
@@ -620,6 +658,10 @@ static int fsl_asrc_dai_hw_params(struct snd_pcm_substream *substream,
 		config.output_sample_rate = rate;
 	}
 
+	fsl_asrc_select_clk(asrc_priv, pair,
+			    config.input_sample_rate,
+			    config.output_sample_rate);
+
 	ret = fsl_asrc_config_pair(pair, false);
 	if (ret) {
 		dev_err(dai->dev, "fail to config asrc pair\n");
-- 
2.21.0

Re: [PATCH v3] ASoC: fsl_asrc: Add an option to select internal ratio mode

[Fabio Estevam]

On Tue, Jun 30, 2020 at 11:07 AM Shengjiu Wang <shengjiu.wang@nxp.com> wrote:
>
> The ASRC not only supports ideal ratio mode, but also supports
> internal ratio mode.
>
> For internal rato mode, the rate of clock source should be divided
> with no remainder by sample rate, otherwise there is sound
> distortion.
>
> Add function fsl_asrc_select_clk() to find proper clock source for
> internal ratio mode, if the clock source is available then internal
> ratio mode will be selected.
>
> With change, the ideal ratio mode is not the only option for user.
>
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>

Reviewed-by: Fabio Estevam <festevam@gmail.com>

Re: [PATCH v3] ASoC: fsl_asrc: Add an option to select internal ratio mode

[Nicolin Chen]

On Tue, Jun 30, 2020 at 09:56:07PM +0800, Shengjiu Wang wrote:
> The ASRC not only supports ideal ratio mode, but also supports
> internal ratio mode.
> 
> For internal rato mode, the rate of clock source should be divided
> with no remainder by sample rate, otherwise there is sound
> distortion.
> 
> Add function fsl_asrc_select_clk() to find proper clock source for
> internal ratio mode, if the clock source is available then internal
> ratio mode will be selected.
> 
> With change, the ideal ratio mode is not the only option for user.
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>

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

Re: [PATCH v3] ASoC: fsl_asrc: Add an option to select internal ratio mode

[Mark Brown]

On Tue, 30 Jun 2020 21:56:07 +0800, Shengjiu Wang wrote:
> The ASRC not only supports ideal ratio mode, but also supports
> internal ratio mode.
> 
> For internal rato mode, the rate of clock source should be divided
> with no remainder by sample rate, otherwise there is sound
> distortion.
> 
> [...]

Applied to

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

Thanks!

[1/1] ASoC: fsl_asrc: Add an option to select internal ratio mode
      commit: d0250cf4f2abfbea64ed247230f08f5ae23979f0

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