[PATCH 5/5] ASoC: fsl-asoc-card: reduce WM8904 PLL ratio to meet frequency limit

[Shengjiu Wang]

WM8904 has a 27 MHz PLL frequency limit. The current S24_LE PLL ratio
of 384 exceeds this at high sample rates (96 kHz × 384 = 36.864 MHz).

Reduce the ratio to 192 for WM8904, keeping PLL within limits at all
supported rates (96 kHz × 192 = 18.432 MHz).

Add codec-specific pll_ratio_s24 field, default 384, override to 192
for WM8904.

Signed-off-by: Shengjiu Wang <shengjiu.wang at nxp.com>
---
 sound/soc/fsl/fsl-asoc-card.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/sound/soc/fsl/fsl-asoc-card.c b/sound/soc/fsl/fsl-asoc-card.c
index 36c789f15582..e72ce2fa9e9e 100644
--- a/sound/soc/fsl/fsl-asoc-card.c
+++ b/sound/soc/fsl/fsl-asoc-card.c
@@ -60,6 +60,9 @@ static const u32 cs42888_channels[] = {
  * @mclk_id: MCLK (or main clock) id for set_sysclk()
  * @fll_id: FLL (or secordary clock) id for set_sysclk()
  * @pll_id: PLL id for set_pll()
+ * @pll_ratio_s24: PLL output ratio for S24_LE format (PLL_freq = sample_rate × ratio)
+ *                 Default is 384, but some codecs (e.g., WM8904) require lower values
+ *                 to stay within PLL frequency limits
  */
 struct codec_priv {
 	struct clk *mclk;
@@ -68,6 +71,7 @@ struct codec_priv {
 	u32 mclk_id;
 	int fll_id;
 	int pll_id;
+	int pll_ratio_s24;
 };
 
 /**
@@ -242,7 +246,7 @@ static int fsl_asoc_card_hw_params(struct snd_pcm_substream *substream,
 
 		if (codec_priv->pll_id >= 0 && codec_priv->fll_id >= 0) {
 			if (priv->sample_format == SNDRV_PCM_FORMAT_S24_LE)
-				pll_out = priv->sample_rate * 384;
+				pll_out = priv->sample_rate * codec_priv->pll_ratio_s24;
 			else
 				pll_out = priv->sample_rate * 256;
 
@@ -806,6 +810,7 @@ static int fsl_asoc_card_probe(struct platform_device *pdev)
 	for (codec_idx = 0; codec_idx < 2; codec_idx++) {
 		priv->codec_priv[codec_idx].fll_id = -1;
 		priv->codec_priv[codec_idx].pll_id = -1;
+		priv->codec_priv[codec_idx].pll_ratio_s24 = 384;
 	}
 
 	/* Diversify the card configurations */
@@ -912,6 +917,7 @@ static int fsl_asoc_card_probe(struct platform_device *pdev)
 		priv->codec_priv[0].mclk_id = WM8904_FLL_MCLK;
 		priv->codec_priv[0].fll_id = WM8904_CLK_FLL;
 		priv->codec_priv[0].pll_id = WM8904_FLL_MCLK;
+		priv->codec_priv[0].pll_ratio_s24 = 192;
 		priv->dai_fmt |= SND_SOC_DAIFMT_CBP_CFP;
 	} else if (of_device_is_compatible(np, "fsl,imx-audio-spdif")) {
 		ret = fsl_asoc_card_spdif_init(codec_np, cpu_np, codec_dai_name, priv);
-- 
2.34.1