static int acp5x_8821_startup(struct snd_pcm_substream *substream)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
-       struct snd_soc_pcm_runtime *rtd = substream->private_data;
+       struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
        struct snd_soc_card *card = rtd->card;
        struct acp5x_platform_info *machine = snd_soc_card_get_drvdata(card);
 
 static int acp5x_nau8821_hw_params(struct snd_pcm_substream *substream,
                                   struct snd_pcm_hw_params *params)
 {
-       struct snd_soc_pcm_runtime *rtd = substream->private_data;
+       struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
        struct snd_soc_card *card = rtd->card;
        struct snd_soc_dai *codec_dai =
                        snd_soc_card_get_codec_dai(card,
 static int acp5x_cs35l41_startup(struct snd_pcm_substream *substream)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
-       struct snd_soc_pcm_runtime *rtd = substream->private_data;
+       struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
        struct snd_soc_card *card = rtd->card;
        struct acp5x_platform_info *machine = snd_soc_card_get_drvdata(card);
 
 static int acp5x_cs35l41_hw_params(struct snd_pcm_substream *substream,
                                   struct snd_pcm_hw_params *params)
 {
-       struct snd_soc_pcm_runtime *rtd = substream->private_data;
+       struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
        struct snd_soc_card *card = rtd->card;
        struct snd_soc_dai *codec_dai;
        int ret, i;