ASoC: imx-rpmsg: Add DSD format support with dynamic DAI format switching

Add hw_params callback to dynamically switch DAI format between I2S
and PDM based on audio stream format. When DSD formats are detected,
the DAI format is switched to PDM mode.

Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
Link: https://patch.msgid.link/20260326055614.3614104-1-chancel.liu@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/fsl/imx-rpmsg.c b/sound/soc/fsl/imx-rpmsg.c
index 76a8e68c1b620c69b7b49a700b7ccbaec21f8525..40e0043cfe15eeb387f26f4fac36bde0c1b79a42 100644 (file)
--- a/sound/soc/fsl/imx-rpmsg.c
+++ b/sound/soc/fsl/imx-rpmsg.c
@@ -30,6 +30,53 @@ static const struct snd_soc_dapm_widget imx_rpmsg_dapm_widgets[] = {
        SND_SOC_DAPM_MIC("Main MIC", NULL),
 };
 
+static int imx_rpmsg_hw_params(struct snd_pcm_substream *substream,
+                              struct snd_pcm_hw_params *params)
+{
+       struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
+       struct snd_soc_dai *codec_dai = snd_soc_rtd_to_codec(rtd, 0);
+       struct snd_soc_dai *cpu_dai = snd_soc_rtd_to_cpu(rtd, 0);
+       snd_pcm_format_t format = params_format(params);
+       struct device *dev = rtd->card->dev;
+       unsigned int fmt = rtd->dai_link->dai_fmt;
+       bool format_is_dsd = false;
+       int ret;
+
+       switch (format) {
+       case SNDRV_PCM_FORMAT_DSD_U8:
+       case SNDRV_PCM_FORMAT_DSD_U16_LE:
+       case SNDRV_PCM_FORMAT_DSD_U16_BE:
+       case SNDRV_PCM_FORMAT_DSD_U32_LE:
+       case SNDRV_PCM_FORMAT_DSD_U32_BE:
+               format_is_dsd = true;
+               break;
+       default:
+               format_is_dsd = false;
+               break;
+       }
+
+       if (format_is_dsd)
+               fmt = (rtd->dai_link->dai_fmt & ~SND_SOC_DAIFMT_FORMAT_MASK) |
+                      SND_SOC_DAIFMT_PDM;
+
+       ret = snd_soc_dai_set_fmt(cpu_dai, fmt);
+       if (ret && ret != -ENOTSUPP) {
+               dev_err(dev, "failed to set cpu dai fmt: %d\n", ret);
+               return ret;
+       }
+       ret = snd_soc_dai_set_fmt(codec_dai, fmt);
+       if (ret && ret != -ENOTSUPP) {
+               dev_err(dev, "failed to set codec dai fmt: %d\n", ret);
+               return ret;
+       }
+
+       return 0;
+}
+
+static const struct snd_soc_ops imx_rpmsg_ops = {
+       .hw_params = imx_rpmsg_hw_params,
+};
+
 static int imx_rpmsg_late_probe(struct snd_soc_card *card)
 {
        struct imx_rpmsg *data = snd_soc_card_get_drvdata(card);
@@ -135,6 +182,7 @@ static int imx_rpmsg_probe(struct platform_device *pdev)
        data->dai.dai_fmt = SND_SOC_DAIFMT_I2S |
                            SND_SOC_DAIFMT_NB_NF |
                            SND_SOC_DAIFMT_CBC_CFC;
+       data->dai.ops = &imx_rpmsg_ops;
 
        /*
         * i.MX rpmsg sound cards work on codec slave mode. MCLK will be