ASoC: dmaengine: Support custom channel names

Some devices have more than just simple TX and RX DMA channels, for example
modern Samsung I2S IPs support a secondary transmit DMA stream which is
mixed into the primary stream during playback. Allow such devices to
specify the names of the channels to be requested in their dma_data.

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>

2 files changed, 18 insertions, 1 deletions

diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h
index 83b2c3e95a1a..15017311f2e9 100644
--- a/include/sound/dmaengine_pcm.h
+++ b/include/sound/dmaengine_pcm.h
@@ -61,6 +61,7 @@ struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream)
  * @slave_id: Slave requester id for the DMA channel.
  * @filter_data: Custom DMA channel filter data, this will usually be used when
  * requesting the DMA channel.
+ * @chan_name: Custom channel name to use when requesting DMA channel.
  * @fifo_size: FIFO size of the DAI controller in bytes
  */
 struct snd_dmaengine_dai_dma_data {
@@ -69,6 +70,7 @@ struct snd_dmaengine_dai_dma_data {
         u32 maxburst;
         unsigned int slave_id;
         void *filter_data;
+        const char *chan_name;
         unsigned int fifo_size;
 };
 
@@ -98,6 +100,10 @@ void snd_dmaengine_pcm_set_config_from_dai_data(
  * playback.
  */
 #define SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX BIT(3)
+/*
+ * The PCM streams have custom channel names specified.
+ */
+#define SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME BIT(4)
 
 /**
  * struct snd_dmaengine_pcm_config - Configuration data for dmaengine based PCM
diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
index 99f9495c1c40..793cd6c246f6 100644
--- a/sound/soc/soc-generic-dmaengine-pcm.c
+++ b/sound/soc/soc-generic-dmaengine-pcm.c
@@ -183,6 +183,8 @@ static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
 {
         struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
         const struct snd_dmaengine_pcm_config *config = pcm->config;
+        struct device *dev = rtd->platform->dev;
+        struct snd_dmaengine_dai_dma_data *dma_data;
         struct snd_pcm_substream *substream;
         size_t prealloc_buffer_size;
         size_t max_buffer_size;
@@ -203,6 +205,13 @@ static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
                 if (!substream)
                         continue;
 
+                dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
+
+                if (!pcm->chan[i] &&
+                    (pcm->flags & SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME))
+                        pcm->chan[i] = dma_request_slave_channel(dev,
+                                dma_data->chan_name);
+
                 if (!pcm->chan[i] && (pcm->flags & SND_DMAENGINE_PCM_FLAG_COMPAT)) {
                         pcm->chan[i] = dmaengine_pcm_compat_request_channel(rtd,
                                 substream);
@@ -275,7 +284,9 @@ static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
 {
         unsigned int i;
 
-        if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_DT) || !dev->of_node)
+        if ((pcm->flags & (SND_DMAENGINE_PCM_FLAG_NO_DT |
+                           SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME)) ||
+            !dev->of_node)
                 return;
 
         if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) {