[alsa-devel] [PATCH] ASoC: Set SNDRV_PCM_INFO_JOINT_DUPLEX for PCMs with symmetry constraints

[Lars-Peter Clausen]

If there are symmetry constraints between the playback and the capture channel
set the SNDRV_PCM_INFO_JOINT_DUPLEX flag to let userspace know about this.

Signed-off-by: Lars-Peter Clausen <lars at metafoo.de>
---
 sound/soc/soc-pcm.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 22af038..eb340a8 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -180,6 +180,21 @@ static int soc_pcm_params_symmetry(struct snd_pcm_substream *substream,
 	return 0;
 }
 
+static bool soc_pcm_has_symmetry(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_dai_driver *cpu_driver = rtd->cpu_dai->driver;
+	struct snd_soc_dai_driver *codec_driver = rtd->codec_dai->driver;
+	struct snd_soc_dai_link *link = rtd->dai_link;
+
+	return cpu_driver->symmetric_rates || codec_driver->symmetric_rates ||
+		link->symmetric_rates || cpu_driver->symmetric_channels ||
+		codec_driver->symmetric_channels || link->symmetric_channels ||
+		cpu_driver->symmetric_samplebits ||
+		codec_driver->symmetric_samplebits ||
+		link->symmetric_samplebits;
+}
+
 /*
  * List of sample sizes that might go over the bus for parameter
  * application.  There ought to be a wildcard sample size for things
@@ -316,6 +331,9 @@ static int soc_pcm_open(struct snd_pcm_substream *substream)
 			&cpu_dai_drv->capture);
 	}
 
+	if (soc_pcm_has_symmetry(substream))
+		runtime->hw.info |= SNDRV_PCM_INFO_JOINT_DUPLEX;
+
 	ret = -EINVAL;
 	if (!runtime->hw.rates) {
 		printk(KERN_ERR "ASoC: %s <-> %s No matching rates\n",
-- 
1.8.0