On Sun, Feb 07, 2021 at 06:23:50PM +0800, Shengjiu Wang wrote:

+static int fsl_rpmsg_hw_params(struct snd_pcm_substream *substream,
+			       struct snd_pcm_hw_params *params,
+			       struct snd_soc_dai *dai)
+{

...

+	ret = clk_prepare_enable(rpmsg->mclk);
+	if (ret)
+		dev_err(dai->dev, "failed to enable mclk: %d\n", ret);
+
+	return ret;
+}
+
+static int fsl_rpmsg_hw_free(struct snd_pcm_substream *substream,
+			     struct snd_soc_dai *dai)
+{
+	struct fsl_rpmsg *rpmsg = snd_soc_dai_get_drvdata(dai);
+
+	clk_disable_unprepare(rpmsg->mclk);

hw_params() can be called multiple times and there's no need for it to
be balanced with hw_free(), I'd move this to a different callback (DAPM
should work well).