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ASoC: fsl-asoc-card: reduce WM8904 PLL ratio to meet frequency limit

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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@nxp.com>
Link: https://patch.msgid.link/20260429100028.2739711-6-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Shengjiu Wang 2026-04-29 18:00:27 +08:00 committed by Mark Brown
parent fa7d8ea56c
commit 99b5316f08
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 7 additions and 1 deletions
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8
sound/soc/fsl/fsl-asoc-card.c
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@ -75,6 +75,9 @@ static const struct snd_pcm_hw_constraint_list cs42888_channel_constraints = {
* @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;
@ -83,6 +86,7 @@ struct codec_priv {
u32 mclk_id;
int fll_id;
int pll_id;
int pll_ratio_s24;
};
/**
@ -255,7 +259,7 @@ 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;
@ -815,6 +819,7 @@ 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 */
@ -935,6 +940,7 @@ 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);