ASoC: Intel: Skylake: Constrain the audio devices

In ref configuration for Skylake, we support only 16bit, 48KHz,
stereo audio, so specify these as constrains for the devices
Signed-off-by: Jeeja KP <jeeja.kp@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/boards/skl_rt286.c

@@ -104,6 +104,53 @@ static int skylake_rt286_codec_init(struct snd_soc_pcm_runtime *rtd)
 	return 0;
 }
 
+static unsigned int rates[] = {
+	48000,
+};
+
+static struct snd_pcm_hw_constraint_list constraints_rates = {
+	.count = ARRAY_SIZE(rates),
+	.list  = rates,
+	.mask = 0,
+};
+
+static unsigned int channels[] = {
+	2,
+};
+
+static struct snd_pcm_hw_constraint_list constraints_channels = {
+	.count = ARRAY_SIZE(channels),
+	.list = channels,
+	.mask = 0,
+};
+
+static int skl_fe_startup(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	/*
+	 * on this platform for PCM device we support,
+	 *	48Khz
+	 *	stereo
+	 *	16 bit audio
+	 */
+
+	runtime->hw.channels_max = 2;
+	snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
+					   &constraints_channels);
+
+	runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
+	snd_pcm_hw_constraint_msbits(runtime, 0, 16, 16);
+
+	snd_pcm_hw_constraint_list(runtime, 0,
+				SNDRV_PCM_HW_PARAM_RATE, &constraints_rates);
+
+	return 0;
+}
+
+static const struct snd_soc_ops skylake_rt286_fe_ops = {
+	.startup = skl_fe_startup,
+};
 
 static int skylake_ssp0_fixup(struct snd_soc_pcm_runtime *rtd,
 			struct snd_pcm_hw_params *params)
@@ -160,6 +207,7 @@ static struct snd_soc_dai_link skylake_rt286_dais[] = {
 			SND_SOC_DPCM_TRIGGER_POST
 		},
 		.dpcm_playback = 1,
+		.ops = &skylake_rt286_fe_ops,
 	},
 	{
 		.name = "Skl Audio Capture Port",
@@ -175,6 +223,7 @@ static struct snd_soc_dai_link skylake_rt286_dais[] = {
 			SND_SOC_DPCM_TRIGGER_POST
 		},
 		.dpcm_capture = 1,
+		.ops = &skylake_rt286_fe_ops,
 	},
 	{
 		.name = "Skl Audio Reference cap",