ASoC: rsnd: ssiu: Add shared SSI reset controller support

The RZ/G3E SoC exposes a single shared "ssi-all" reset that gates all
SSI/SSIU modules. Acquire it at SSIU probe and pass it through
rsnd_mod_init() so it is wired into the rsnd_mod->rstc plumbing.

devm_reset_control_get_optional_shared() returns NULL when no reset is
described in DT, leaving existing R-Car generations unaffected.

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/20260525110230.4014435-10-john.madieu.xa@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: John Madieu

sound/soc/renesas/rcar/ssiu.c

@@ -510,6 +510,7 @@ int rsnd_ssiu_probe(struct rsnd_priv *priv)
 {
 	struct device *dev = rsnd_priv_to_dev(priv);
 	struct device_node *node __free(device_node) = rsnd_ssiu_of_node(priv);
+	struct reset_control *rstc;
 	struct rsnd_ssiu *ssiu;
 	struct rsnd_mod_ops *ops;
 	const int *list = NULL;
@@ -564,6 +565,12 @@ int rsnd_ssiu_probe(struct rsnd_priv *priv)
 		}
 	}
 
+	/* Acquire shared reset once for all SSIU modules */
+	rstc = devm_reset_control_get_optional_shared(dev, "ssi-all");
+	if (IS_ERR(rstc))
+		return dev_err_probe(dev, PTR_ERR(rstc),
+				     "failed to get ssi-all reset\n");
+
 	for_each_rsnd_ssiu(ssiu, priv, i) {
 		int ret;
 
@@ -586,7 +593,7 @@ int rsnd_ssiu_probe(struct rsnd_priv *priv)
 		}
 
 		ret = rsnd_mod_init(priv, rsnd_mod_get(ssiu),
-				    ops, NULL, NULL, RSND_MOD_SSIU, i);
+				    ops, NULL, rstc, RSND_MOD_SSIU, i);
 		if (ret)
 			return ret;
 	}