[PATCH v2 v2 1/2] ASoC: qcom: sdm845: apply the SLIMbus channel map to wcd934x only

[Mohammad Rafi Shaik <mohammad.rafi.shaik@oss.qualcomm.com>]

On sdm845 boards the SLIMbus backends are described in DT with several
codec DAIs on the same DAI link. The SLIM playback link lists the two
WSA881x speakers and the SoundWire master embedded in wcd934x next to
the wcd934x SLIMbus AIF:

	codec {
		sound-dai = <&left_spkr>, <&right_spkr>,
			    <&swm 0>, <&wcd9340 AIF1_PB>;
	};

sdm845_dai_init() walks all codec DAIs of such a link and calls
snd_soc_dai_set_channel_map() on each of them with the hardcoded wcd934x
SLIMbus channel numbers, 128..143 for TX and 144..156 for RX. Those
channel numbers are only meaningful for a codec attached over SLIMbus,
and programming them into the SoundWire master DAI configures bogus port
channel masks on it.

So far this has been harmless only because neither the qcom SoundWire
master nor the WSA881x codecs implement .set_channel_map, so the call
returns -ENOTSUPP and is silently ignored. It starts corrupting the
SoundWire port configuration as soon as the master DAI implements that
op, which the next patch does.

The channel map is not the only wcd934x specific setup in this loop. The
codec MCLK rate (WCD934X_DEFAULT_MCLK_RATE) and the headset jack belong
to wcd934x as well and are broadcast to the SoundWire DAIs for the same
reason, relying on them returning -ENOTSUPP.

Match the wcd934x codec explicitly by its driver name and skip the other
codec DAIs of the link, so that each codec only gets the setup that is
meant for it.

The bus type of the DAI device cannot be used to tell these codecs
apart: wcd934x is a SLIMbus device driven by an MFD driver that creates
the ASoC component and the SoundWire master as platform children of it
(wcd934x_devices[] in drivers/mfd/wcd934x.c), so both DAIs live on the
platform bus with the same SLIMbus parent.

Signed-off-by: Mohammad Rafi Shaik <mohammad.rafi.shaik@oss.qualcomm.com>
---
 sound/soc/qcom/sdm845.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/sound/soc/qcom/sdm845.c b/sound/soc/qcom/sdm845.c
index 85951397cb2b..7137c9c14d8f 100644
--- a/sound/soc/qcom/sdm845.c
+++ b/sound/soc/qcom/sdm845.c
@@ -234,6 +234,19 @@ static void sdm845_jack_free(struct snd_jack *jack)
 	snd_soc_component_set_jack(component, NULL, NULL);
 }
 
+/*
+ * The SLIMbus backends list the wcd934x codec, the SoundWire master
+ * embedded in wcd934x and its SoundWire speaker codecs as codec DAIs of
+ * the same DAI link.  Only the wcd934x DAIs take the SLIMbus channel map
+ * and the codec clock and jack setup below.
+ */
+static bool sdm845_dai_is_wcd934x(struct snd_soc_dai *dai)
+{
+	struct device_driver *drv = dai->dev->driver;
+
+	return drv && !strcmp(drv->name, "wcd934x-codec");
+}
+
 static int sdm845_dai_init(struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_soc_component *component;
@@ -301,6 +314,9 @@ static int sdm845_dai_init(struct snd_soc_pcm_runtime *rtd)
 			return 0;
 
 		for_each_rtd_codec_dais(rtd, i, codec_dai) {
+			if (!sdm845_dai_is_wcd934x(codec_dai))
+				continue;
+
 			rval = snd_soc_dai_set_channel_map(codec_dai,
 							  ARRAY_SIZE(tx_ch),
 							  tx_ch,

-- 
2.34.1