ASoC: rsnd: Support unprefixed DT node names for RZ/G3E

The RZ/G3E device tree binding uses standard unprefixed node names
("ssi", "ssiu", "src", "dvc", "mix", "ctu") instead of the legacy
"rcar_sound," prefixed names used by R-Car bindings.

Convert rsnd_parse_of_node() from a macro into a function that tries
the legacy prefixed name first, then falls back to the unprefixed name
by stripping the "rcar_sound," prefix. This makes the driver work
transparently with both old and new bindings.

While at it, update the related comments in dma.c, ssi.c and ssiu.c
that reference the hardcoded "rcar_sound,ssiu" / "rcar_sound,ssi"
names to note that the driver now accepts both the prefixed and the
unprefixed forms.

Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://patch.msgid.link/20260525110230.4014435-18-john.madieu.xa@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: John Madieu

sound/soc/renesas/rcar/core.c

@@ -1301,6 +1301,40 @@ rsnd_devm_reset_control_get_optional_indexed(struct device *dev,
 	return devm_reset_control_get_optional(dev, name);
 }
 
+/*
+ * Strip the "rcar_sound," prefix from a legacy node name.
+ *
+ * The RZ/G3E binding uses unprefixed sub-node names (e.g. "ssi",
+ * "ssiu") while earlier R-Car bindings use the legacy "rcar_sound,*"
+ * form. This helper returns the unprefixed portion (the part after
+ * the comma) or NULL if there is no prefix.
+ *
+ * Centralising the convention here keeps every call site consistent.
+ */
+static const char *rsnd_node_name_strip_prefix(const char *name)
+{
+	const char *comma = strchr(name, ',');
+
+	return comma ? comma + 1 : NULL;
+}
+
+struct device_node *rsnd_parse_of_node(struct rsnd_priv *priv, const char *name)
+{
+	struct device_node *np = rsnd_priv_to_dev(priv)->of_node;
+	struct device_node *node;
+	const char *unprefixed;
+
+	node = of_get_child_by_name(np, name);
+	if (node)
+		return node;
+
+	unprefixed = rsnd_node_name_strip_prefix(name);
+	if (unprefixed)
+		node = of_get_child_by_name(np, unprefixed);
+
+	return node;
+}
+
 static struct device_node*
 	rsnd_pick_endpoint_node_for_ports(struct device_node *e_ports,
 					  struct device_node *e_port)

sound/soc/renesas/rcar/dma.c

@@ -794,11 +794,11 @@ static void rsnd_dma_of_path(struct rsnd_mod *this,
 	int nr, i, idx;
 
 	/*
-	 * It should use "rcar_sound,ssiu" on DT.
-	 * But, we need to keep compatibility for old version.
+	 * It should use "rcar_sound,ssiu" (R-Car) or "ssiu" (RZ/G3E) on DT.
+	 * We need to keep compatibility for old version.
 	 *
-	 * If it has "rcar_sound.ssiu", it will be used.
-	 * If not, "rcar_sound.ssi" will be used.
+	 * If it has "rcar_sound.ssiu" or "ssiu", it will be used.
+	 * If not, "rcar_sound.ssi" or "ssi" will be used.
 	 * see
 	 *	rsnd_ssiu_dma_req()
 	 *	rsnd_ssi_dma_req()

sound/soc/renesas/rcar/rsnd.h

@@ -501,8 +501,8 @@ rsnd_devm_reset_control_get_optional_indexed(struct device *dev,
 /*
  * DT
  */
-#define rsnd_parse_of_node(priv, node)					\
-	of_get_child_by_name(rsnd_priv_to_dev(priv)->of_node, node)
+struct device_node *rsnd_parse_of_node(struct rsnd_priv *priv, const char *name);
+
 #define RSND_NODE_DAI	"rcar_sound,dai"
 #define RSND_NODE_SSI	"rcar_sound,ssi"
 #define RSND_NODE_SSIU	"rcar_sound,ssiu"

sound/soc/renesas/rcar/ssi.c

@@ -1009,11 +1009,11 @@ static struct dma_chan *rsnd_ssi_dma_req(struct rsnd_dai_stream *io,
 	char *name;
 
 	/*
-	 * It should use "rcar_sound,ssiu" on DT.
-	 * But, we need to keep compatibility for old version.
+	 * It should use "rcar_sound,ssiu" (R-Car) or "ssiu" (RZ/G3E) on DT.
+	 * We need to keep compatibility for old version.
 	 *
-	 * If it has "rcar_sound.ssiu", it will be used.
-	 * If not, "rcar_sound.ssi" will be used.
+	 * If it has "rcar_sound.ssiu" or "ssiu", it will be used.
+	 * If not, "rcar_sound.ssi" or "ssi" will be used.
 	 * see
 	 *	rsnd_ssiu_dma_req()
 	 *	rsnd_dma_of_path()

sound/soc/renesas/rcar/ssiu.c

@@ -400,11 +400,11 @@ static struct dma_chan *rsnd_ssiu_dma_req(struct rsnd_dai_stream *io,
 	char *name;
 
 	/*
-	 * It should use "rcar_sound,ssiu" on DT.
-	 * But, we need to keep compatibility for old version.
+	 * It should use "rcar_sound,ssiu" (R-Car) or "ssiu" (RZ/G3E) on DT.
+	 * We need to keep compatibility for old versions.
 	 *
-	 * If it has "rcar_sound.ssiu", it will be used.
-	 * If not, "rcar_sound.ssi" will be used.
+	 * If it has "rcar_sound.ssiu" or "ssiu", it will be used.
+	 * If not, "rcar_sound.ssi" or "ssi" will be used.
 	 * see
 	 *	rsnd_ssi_dma_req()
 	 *	rsnd_dma_of_path()