sound: fsl_hdmi: Add rules to adjust constraints dynamically.

This patch will modify the sample rate and channel count constraints
depending on each other. This handles sinks, that report different
supported sample rates for stereo and multi-channel.

Signed-off-by: Rudi <r.ihle@s-t.de>

sound/soc/fsl/fsl_hdmi.c

@@ -335,6 +335,83 @@ static void fsl_hdmi_get_playback_channels(void)
 		pr_debug("%s: constraint = %d channels\n", __func__, playback_channels[i]);
 }
 
+static int fsl_hw_rule_channels_by_rate(struct snd_pcm_hw_params *params,
+                                        struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval	*r = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
+	struct snd_interval	*c = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
+	int    			i;
+	u8     			m;
+	struct snd_interval	n;
+
+	if (snd_interval_single(r)) {
+		m = 0;
+		for (i = 0; i < HDMI_MAX_RATES; i++) {
+			if (snd_interval_min(r) == cea_audio_rates[i]) {
+				m = 1 << i;
+				break;
+			}
+		}
+
+		if (m) {
+			snd_interval_any(&n);
+			n.min = n.max = 2;
+
+			for (i = 1; i < ARRAY_SIZE(edid_cfg.sample_rates); i++) {
+				if (!(edid_cfg.sample_rates[i] & m))
+					break;
+				n.max += 2;
+			}
+
+			pr_debug("%s: rate = %d, channels = %d..%d\n",
+				 __func__, r->min, n.min, n.max);
+
+			return snd_interval_refine(c, &n);
+		}
+	}
+
+	return 0;
+}
+
+static int fsl_hw_rule_rate_by_channels(struct snd_pcm_hw_params *params,
+                                        struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval	*r = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
+	struct snd_interval	*c = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
+	int    			i, rate;
+	u8     			m;
+	struct snd_interval	n;
+
+	if (snd_interval_single(c)) {
+		i = (snd_interval_min(c) - 1) / 2;
+		m = edid_cfg.sample_rates[i];
+
+		if (m) {
+			snd_interval_any(&n);
+			n.min = 192000;
+			n.max = 32000;
+
+			for (i = 0; i < HDMI_MAX_RATES; i++, m >>= 1) {
+				if (!(m & 1))
+					  continue;
+
+				rate = cea_audio_rates[i];
+				if ( rate < n.min)
+					n.min = rate;
+				if ( rate > n.max)
+					n.max = rate;
+			}
+
+			pr_debug("%s: channels = %d, rates = %d..%d\n",
+				 __func__, c->min, n.min, n.max);
+
+			return snd_interval_refine(r, &n);
+		}
+	}
+
+	return 0;
+}
+
 static int fsl_hdmi_update_constraints(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
@@ -367,6 +444,18 @@ static int fsl_hdmi_update_constraints(struct snd_pcm_substream *substream)
 	if (ret < 0)
 		return ret;
 
+	ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
+			fsl_hw_rule_channels_by_rate, NULL,
+			SNDRV_PCM_HW_PARAM_RATE, -1);
+	if (ret < 0)
+		return ret;
+
+	ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
+			fsl_hw_rule_rate_by_channels, NULL,
+			SNDRV_PCM_HW_PARAM_CHANNELS, -1);
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }