[alsa-devel] [PATCH] ASoC: sgtl5000: add multi endpoint support

[Marek Vasut]

Support multiple endpoints on SGTL5000 codec port when used in
of_graph context.

This patch allows to share the codec port between two CPU DAIs.

Example:

Custom STM32MP157C board uses SGTL5000 audio codec. This codec is
connected to two serial audio interfaces, which are configured
either as rx or tx.

>From AsoC point of view the topolgy is the following:
// 2 CPU DAIs (SAI2A/B), 1 Codec (SGTL5000)
Playback: CPU-A-DAI(slave) -> (master)CODEC-DAI/port0
Record:   CPU-B-DAI(slave) <- (master)CODEC-DAI/port0

In the DT two endpoints have to be associated to the codec port:
sgtl5000_port: port {
    sgtl5000_tx_endpoint: endpoint at 0 {
	    remote-endpoint = <&sai2a_endpoint>;
    };
    sgtl5000_rx_endpoint: endpoint at 1 {
	    remote-endpoint = <&sai2b_endpoint>;
    };
};

However, when the audio graph card parses the codec nodes, it expects
to find DAI interface indexes matching the endpoints indexes.

The current patch forces the use of DAI id 0 for both endpoints,
which allows to share the codec DAI between the two CPU DAIs
for playback and capture streams respectively.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Mark Brown <broonie at kernel.org>
---
NOTE: This is the same as commit ad6bb3067c4d
      ("ASoC: cs42l51: add multi endpoint support")
---
 sound/soc/codecs/sgtl5000.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index aa1f9637d8950..93da6b58c97df 100644
--- a/sound/soc/codecs/sgtl5000.c
+++ b/sound/soc/codecs/sgtl5000.c
@@ -1513,6 +1513,13 @@ static int sgtl5000_probe(struct snd_soc_component *component)
 	return ret;
 }
 
+static int sgtl5000_of_xlate_dai_id(struct snd_soc_component *component,
+				    struct device_node *endpoint)
+{
+	/* return dai id 0, whatever the endpoint index */
+	return 0;
+}
+
 static const struct snd_soc_component_driver sgtl5000_driver = {
 	.probe			= sgtl5000_probe,
 	.set_bias_level		= sgtl5000_set_bias_level,
@@ -1522,6 +1529,7 @@ static const struct snd_soc_component_driver sgtl5000_driver = {
 	.num_dapm_widgets	= ARRAY_SIZE(sgtl5000_dapm_widgets),
 	.dapm_routes		= sgtl5000_dapm_routes,
 	.num_dapm_routes	= ARRAY_SIZE(sgtl5000_dapm_routes),
+	.of_xlate_dai_id	= sgtl5000_of_xlate_dai_id,
 	.suspend_bias_off	= 1,
 	.idle_bias_on		= 1,
 	.use_pmdown_time	= 1,
-- 
2.24.1