From 2c9ebfadabcf95aec069a27e6469ea8674d254b0 Mon Sep 17 00:00:00 2001
From: Mark Brown <broonie@opensource.wolfsonmicro.com>
Date: Tue, 7 Apr 2009 18:10:13 +0100
Subject: [PATCH] --- yaml --- r: 148176 b: refs/heads/master c:
 06f409d76f1d382167eb1cadde2e23a73272865d h: refs/heads/master v: v3

---
 [refs]                        |  2 +-
 trunk/include/sound/soc-dai.h |  1 +
 trunk/include/sound/soc.h     |  6 ++++++
 trunk/sound/soc/soc-core.c    | 38 +++++++++++++++++++++++++++++++++++
 4 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index f621a1b6bdc6..11053fd2c272 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6553e192d48af88184029066c30c9464516ea0b7
+refs/heads/master: 06f409d76f1d382167eb1cadde2e23a73272865d
diff --git a/trunk/include/sound/soc-dai.h b/trunk/include/sound/soc-dai.h
index 13676472ddfc..22b729fbbf84 100644
--- a/trunk/include/sound/soc-dai.h
+++ b/trunk/include/sound/soc-dai.h
@@ -208,6 +208,7 @@ struct snd_soc_dai {
 	/* DAI capabilities */
 	struct snd_soc_pcm_stream capture;
 	struct snd_soc_pcm_stream playback;
+	unsigned int symmetric_rates:1;
 
 	/* DAI runtime info */
 	struct snd_pcm_runtime *runtime;
diff --git a/trunk/include/sound/soc.h b/trunk/include/sound/soc.h
index a40bc6f316fc..b1f2f8819fea 100644
--- a/trunk/include/sound/soc.h
+++ b/trunk/include/sound/soc.h
@@ -417,6 +417,12 @@ struct snd_soc_dai_link  {
 	/* codec/machine specific init - e.g. add machine controls */
 	int (*init)(struct snd_soc_codec *codec);
 
+	/* Symmetry requirements */
+	unsigned int symmetric_rates:1;
+
+	/* Symmetry data - only valid if symmetry is being enforced */
+	unsigned int rate;
+
 	/* DAI pcm */
 	struct snd_pcm *pcm;
 };
diff --git a/trunk/sound/soc/soc-core.c b/trunk/sound/soc/soc-core.c
index 99712f652d0d..dd28009f8969 100644
--- a/trunk/sound/soc/soc-core.c
+++ b/trunk/sound/soc/soc-core.c
@@ -113,6 +113,35 @@ static int soc_ac97_dev_register(struct snd_soc_codec *codec)
 }
 #endif
 
+static int soc_pcm_apply_symmetry(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_device *socdev = rtd->socdev;
+	struct snd_soc_card *card = socdev->card;
+	struct snd_soc_dai_link *machine = rtd->dai;
+	struct snd_soc_dai *cpu_dai = machine->cpu_dai;
+	struct snd_soc_dai *codec_dai = machine->codec_dai;
+	int ret;
+
+	if (codec_dai->symmetric_rates || cpu_dai->symmetric_rates ||
+	    machine->symmetric_rates) {
+		dev_dbg(card->dev, "Symmetry forces %dHz rate\n", 
+			machine->rate);
+
+		ret = snd_pcm_hw_constraint_minmax(substream->runtime,
+						   SNDRV_PCM_HW_PARAM_RATE,
+						   machine->rate,
+						   machine->rate);
+		if (ret < 0) {
+			dev_err(card->dev,
+				"Unable to apply rate symmetry constraint: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
 /*
  * Called by ALSA when a PCM substream is opened, the runtime->hw record is
  * then initialized and any private data can be allocated. This also calls
@@ -221,6 +250,13 @@ static int soc_pcm_open(struct snd_pcm_substream *substream)
 		goto machine_err;
 	}
 
+	/* Symmetry only applies if we've already got an active stream. */
+	if (cpu_dai->active || codec_dai->active) {
+		ret = soc_pcm_apply_symmetry(substream);
+		if (ret != 0)
+			goto machine_err;
+	}
+
 	pr_debug("asoc: %s <-> %s info:\n", codec_dai->name, cpu_dai->name);
 	pr_debug("asoc: rate mask 0x%x\n", runtime->hw.rates);
 	pr_debug("asoc: min ch %d max ch %d\n", runtime->hw.channels_min,
@@ -521,6 +557,8 @@ static int soc_pcm_hw_params(struct snd_pcm_substream *substream,
 		}
 	}
 
+	machine->rate = params_rate(params);
+
 out:
 	mutex_unlock(&pcm_mutex);
 	return ret;