ASoC: SSM2602: assign last substream to the master when shutting down

Fixes crash when shutting down.
Signed-off-by: Cliff Cai <cliff.cai@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/ssm2602.c

@@ -336,11 +336,13 @@ static int ssm2602_startup(struct snd_pcm_substream *substream,
 			master_runtime->sample_bits,
 			master_runtime->rate);
 
+		if (master_runtime->rate != 0)
 			snd_pcm_hw_constraint_minmax(substream->runtime,
 						     SNDRV_PCM_HW_PARAM_RATE,
 						     master_runtime->rate,
 						     master_runtime->rate);
 
+		if (master_runtime->sample_bits != 0)
 			snd_pcm_hw_constraint_minmax(substream->runtime,
 						     SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
 						     master_runtime->sample_bits,
@@ -372,6 +374,11 @@ static void ssm2602_shutdown(struct snd_pcm_substream *substream,
 	struct snd_soc_device *socdev = rtd->socdev;
 	struct snd_soc_codec *codec = socdev->card->codec;
 	struct ssm2602_priv *ssm2602 = codec->private_data;
+
+	if (ssm2602->master_substream == substream)
+		ssm2602->master_substream = ssm2602->slave_substream;
+
+	ssm2602->slave_substream = NULL;
 	/* deactivate */
 	if (!codec->active)
 		ssm2602_write(codec, SSM2602_ACTIVE, 0);