[PATCH v4 10/12] ASoC: rsnd: adg: Add per-SSI ADG and SSIF supply clock management

[John Madieu]

RZ/G3E's ADG module requires explicit clock management for SSI audio
interfaces that differs from R-Car Gen2/Gen3/Gen4:

 - Per-SSI ADG clocks (adg.ssi.N) for each SSI module
 - A shared SSIF supply clock for the SSI subsystem

These clocks are acquired using optional APIs, making them transparent
to platforms that do not require them.

Clock prepare/unprepare is handled in rsnd_adg_clk_control(), which
is called from probe, remove, suspend and resume (all sleepable
contexts). The trigger path (atomic context) only calls
clk_enable/clk_disable, which is atomic-safe and requires no
additional splitting.

Signed-off-by: John Madieu <john.madieu.xa@xxxxxxxxxxxxxx>
---

v4:
 - Move clk_prepare/unprepare for per-SSI ADG and SSIF supply clocks
   into rsnd_adg_clk_control() instead of separate prepare/unprepare
   functions, centralizing clock lifecycle management
 - Return proper errors on clk_enable() failure instead of dev_warn()
 - Eliminates hw_params prepare leak concern since prepare now happens
   once at probe/resume

v3: No changes
v2:
 - Split clock handling into prepare/enable phases for atomic context
   safety

 sound/soc/renesas/rcar/adg.c | 91 +++++++++++++++++++++++++++++++++++-
 1 file changed, 89 insertions(+), 2 deletions(-)

diff --git a/sound/soc/renesas/rcar/adg.c b/sound/soc/renesas/rcar/adg.c
index 813ad5eabba6..9cae3bbefa55 100644
--- a/sound/soc/renesas/rcar/adg.c
+++ b/sound/soc/renesas/rcar/adg.c
@@ -19,6 +19,9 @@
 #define CLKOUT3	3
 #define CLKOUTMAX 4
 
+/* Maximum SSI count for per-SSI clocks */
+#define ADG_SSI_MAX	10
+
 #define BRGCKR_31	(1 << 31)
 #define BRRx_MASK(x) (0x3FF & x)
 
@@ -34,6 +37,9 @@ struct rsnd_adg {
 	struct clk *adg;
 	struct clk *clkin[CLKINMAX];
 	struct clk *clkout[CLKOUTMAX];
+	/* RZ/G3E: per-SSI ADG clocks (adg.ssi.0 through adg.ssi.9) */
+	struct clk *clk_adg_ssi[ADG_SSI_MAX];
+	struct clk *clk_ssif_supply;
 	struct clk *null_clk;
 	struct clk_onecell_data onecell;
 	struct rsnd_mod mod;
@@ -343,8 +349,16 @@ int rsnd_adg_clk_query(struct rsnd_priv *priv, unsigned int rate)
 
 int rsnd_adg_ssi_clk_stop(struct rsnd_mod *ssi_mod)
 {
+	struct rsnd_priv *priv = rsnd_mod_to_priv(ssi_mod);
+	struct rsnd_adg *adg = rsnd_priv_to_adg(priv);
+	int id = rsnd_mod_id(ssi_mod);
+
 	rsnd_adg_set_ssi_clk(ssi_mod, 0);
 
+	/* RZ/G3E: only disable here, unprepare is done in hw_free */
+	clk_disable(adg->clk_adg_ssi[id]);
+	clk_disable(adg->clk_ssif_supply);
+
 	return 0;
 }
 
@@ -354,7 +368,8 @@ int rsnd_adg_ssi_clk_try_start(struct rsnd_mod *ssi_mod, unsigned int rate)
 	struct rsnd_adg *adg = rsnd_priv_to_adg(priv);
 	struct device *dev = rsnd_priv_to_dev(priv);
 	struct rsnd_mod *adg_mod = rsnd_mod_get(adg);
-	int data;
+	int id = rsnd_mod_id(ssi_mod);
+	int ret, data;
 	u32 ckr = 0;
 
 	data = rsnd_adg_clk_query(priv, rate);
@@ -376,6 +391,22 @@ int rsnd_adg_ssi_clk_try_start(struct rsnd_mod *ssi_mod, unsigned int rate)
 		(ckr) ?	adg->brg_rate[ADG_HZ_48] :
 			adg->brg_rate[ADG_HZ_441]);
 
+	/*
+	 * RZ/G3E: enable per-SSI and supply clocks
+	 */
+	ret = clk_enable(adg->clk_adg_ssi[id]);
+	if (ret) {
+		dev_err(dev, "Cannot enable adg.ssi.%d ADG clock\n", id);
+		return ret;
+	}
+
+	ret = clk_enable(adg->clk_ssif_supply);
+	if (ret) {
+		dev_err(dev, "Cannot enable SSIF supply clock\n");
+		clk_disable(adg->clk_adg_ssi[id]);
+		return ret;
+	}
+
 	return 0;
 }
 
@@ -424,9 +455,35 @@ int rsnd_adg_clk_control(struct rsnd_priv *priv, int enable)
 	if (ret < 0)
 		rsnd_adg_clk_disable(priv);
 
+	/* RZ/G3E: per-SSI ADG and SSIF supply clocks */
+	if (enable) {
+		for (i = 0; i < ADG_SSI_MAX; i++) {
+			ret = clk_prepare(adg->clk_adg_ssi[i]);
+			if (ret < 0) {
+				while (--i >= 0)
+					clk_unprepare(adg->clk_adg_ssi[i]);
+				rsnd_adg_clk_disable(priv);
+				return ret;
+			}
+		}
+		ret = clk_prepare(adg->clk_ssif_supply);
+		if (ret < 0) {
+			for (i = 0; i < ADG_SSI_MAX; i++)
+				clk_unprepare(adg->clk_adg_ssi[i]);
+			rsnd_adg_clk_disable(priv);
+			return ret;
+		}
+	}
+
 	/* disable adg */
-	if (!enable)
+	if (!enable) {
+		/* RZ/G3E: unprepare per-SSI and supply clocks */
+		clk_unprepare(adg->clk_ssif_supply);
+		for (i = 0; i < ADG_SSI_MAX; i++)
+			clk_unprepare(adg->clk_adg_ssi[i]);
+
 		clk_disable_unprepare(adg->adg);
+	}
 
 	return ret;
 }
@@ -769,6 +826,31 @@ void rsnd_adg_clk_dbg_info(struct rsnd_priv *priv, struct seq_file *m)
 #define rsnd_adg_clk_dbg_info(priv, m)
 #endif
 
+static int rsnd_adg_get_ssi_clks(struct rsnd_priv *priv)
+{
+	struct rsnd_adg *adg = rsnd_priv_to_adg(priv);
+	struct device *dev = rsnd_priv_to_dev(priv);
+	char name[16];
+	int i;
+
+	/* SSIF supply clock */
+	adg->clk_ssif_supply = devm_clk_get_optional(dev, "ssif_supply");
+	if (IS_ERR(adg->clk_ssif_supply))
+		return dev_err_probe(dev, PTR_ERR(adg->clk_ssif_supply),
+				     "failed to get ssif_supply clock\n");
+
+	/* Per-SSI ADG clocks */
+	for (i = 0; i < ADG_SSI_MAX; i++) {
+		snprintf(name, sizeof(name), "adg.ssi.%d", i);
+		adg->clk_adg_ssi[i] = devm_clk_get_optional(dev, name);
+		if (IS_ERR(adg->clk_adg_ssi[i]))
+			return dev_err_probe(dev, PTR_ERR(adg->clk_adg_ssi[i]),
+					     "failed to get %s clock\n", name);
+	}
+
+	return 0;
+}
+
 int rsnd_adg_probe(struct rsnd_priv *priv)
 {
 	struct reset_control *rstc;
@@ -798,6 +880,11 @@ int rsnd_adg_probe(struct rsnd_priv *priv)
 	if (ret)
 		return ret;
 
+	/* RZ/G3E-specific: per-SSI ADG and SSIF supply clocks */
+	ret = rsnd_adg_get_ssi_clks(priv);
+	if (ret)
+		return ret;
+
 	ret = rsnd_adg_clk_enable(priv);
 	if (ret)
 		return ret;
-- 
2.25.1