[PATCH v4 11/12] ASoC: rsnd: src: Add SRC reset and clock support for RZ/G3E

John Madieu
2026-04-09T09:04:59Z

The RZ/G3E SoC requires explicit SCU (Sampling Rate Converter Unit)
reset and clock management unlike previous R-Car generations:

- scu_clk: SCU module clock
- scu_clkx2: SCU double-rate clock
- scu_supply_clk: SCU supply clock

Without these clocks enabled, the SRC module cannot operate on RZ/G3E.
Add support for the shared SCU reset controller used by the SRC modules
on the Renesas RZ/G3E SoC. All SRC instances are gated by the same "scu"
reset line.

Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
---

Changes:

v4:
- Move shared SCU clocks (scu, scu_x2, scu_supply) from rsnd_priv
variables into new struct rsnd_src_ctrl, following the rsnd_dma_ctrl
pattern for shared non-per-instance module resources
- Keep original declaration order for struct device_node *node

v3: No changes
v2: No changes

sound/soc/renesas/rcar/rsnd.h | 1 +
sound/soc/renesas/rcar/src.c | 59 ++++++++++++++++++++++++++++++++++-
2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/sound/soc/renesas/rcar/rsnd.h b/sound/soc/renesas/rcar/rsnd.h
index 5cf35a1f3e45..8f8e86cb6e62 100644
--- a/sound/soc/renesas/rcar/rsnd.h
+++ b/sound/soc/renesas/rcar/rsnd.h
@@ -680,6 +680,7 @@ struct rsnd_priv {
/*
* below value will be filled on rsnd_src_probe()
*/
+ void *src_ctrl;
void *src;
int src_nr;

diff --git a/sound/soc/renesas/rcar/src.c b/sound/soc/renesas/rcar/src.c
index 8b58cc20e7a8..651ed378c4f7 100644
--- a/sound/soc/renesas/rcar/src.c
+++ b/sound/soc/renesas/rcar/src.c
@@ -54,6 +54,14 @@ struct rsnd_src {
((pos) = (struct rsnd_src *)(priv)->src + i); \
i++)

+struct rsnd_src_ctrl {
+ struct clk *scu;
+ struct clk *scu_x2;
+ struct clk *scu_supply;
+};
+
+#define rsnd_priv_to_src_ctrl(priv) \
+ ((struct rsnd_src_ctrl *)(priv)->src_ctrl)

/*
* image of SRC (Sampling Rate Converter)
@@ -516,6 +524,7 @@ static int rsnd_src_init(struct rsnd_mod *mod,
struct rsnd_priv *priv)
{
struct rsnd_src *src = rsnd_mod_to_src(mod);
+ struct device *dev = rsnd_priv_to_dev(priv);
int ret;

/* reset sync convert_rate */
@@ -526,6 +535,12 @@ static int rsnd_src_init(struct rsnd_mod *mod,
if (ret < 0)
return ret;

+ ret = clk_prepare_enable(rsnd_priv_to_src_ctrl(priv)->scu_supply);
+ if (ret) {
+ dev_err(dev, "Cannot enable scu_supply_clk\n");
+ return ret;
+ }
+
rsnd_src_activation(mod);

rsnd_src_init_convert_rate(io, mod);
@@ -549,6 +564,8 @@ static int rsnd_src_quit(struct rsnd_mod *mod,
src->sync.val =
src->current_sync_rate = 0;

+ clk_disable_unprepare(rsnd_priv_to_src_ctrl(priv)->scu_supply);
+
return 0;
}

@@ -713,6 +730,8 @@ int rsnd_src_probe(struct rsnd_priv *priv)
{
struct device_node *node;
struct device *dev = rsnd_priv_to_dev(priv);
+ struct reset_control *rstc;
+ struct rsnd_src_ctrl *src_ctrl;
struct rsnd_src *src;
struct clk *clk;
char name[RSND_SRC_NAME_SIZE];
@@ -728,6 +747,12 @@ int rsnd_src_probe(struct rsnd_priv *priv)
goto rsnd_src_probe_done;
}

+ src_ctrl = devm_kzalloc(dev, sizeof(*src_ctrl), GFP_KERNEL);
+ if (!src_ctrl) {
+ ret = -ENOMEM;
+ goto rsnd_src_probe_done;
+ }
+
src = devm_kcalloc(dev, nr, sizeof(*src), GFP_KERNEL);
if (!src) {
ret = -ENOMEM;
@@ -736,6 +761,28 @@ int rsnd_src_probe(struct rsnd_priv *priv)

priv->src_nr = nr;
priv->src = src;
+ priv->src_ctrl = src_ctrl;
+
+ src_ctrl->scu = devm_clk_get_optional_enabled(dev, "scu");
+ if (IS_ERR(src_ctrl->scu)) {
+ ret = dev_err_probe(dev, PTR_ERR(src_ctrl->scu),
+ "failed to get scu clock\n");
+ goto rsnd_src_probe_done;
+ }
+
+ src_ctrl->scu_x2 = devm_clk_get_optional_enabled(dev, "scu_x2");
+ if (IS_ERR(src_ctrl->scu_x2)) {
+ ret = dev_err_probe(dev, PTR_ERR(src_ctrl->scu_x2),
+ "failed to get scu_x2 clock\n");
+ goto rsnd_src_probe_done;
+ }
+
+ src_ctrl->scu_supply = devm_clk_get_optional(dev, "scu_supply");
+ if (IS_ERR(src_ctrl->scu_supply)) {
+ ret = dev_err_probe(dev, PTR_ERR(src_ctrl->scu_supply),
+ "failed to get scu_supply clock\n");
+ goto rsnd_src_probe_done;
+ }

i = 0;
for_each_child_of_node_scoped(node, np) {
@@ -759,6 +806,16 @@ int rsnd_src_probe(struct rsnd_priv *priv)
goto rsnd_src_probe_done;
}

+ /*
+ * RZ/G3E uses a shared SCU reset controller for all SRC modules.
+ * R-Car platforms typically don't have SRC reset controls.
+ */
+ rstc = devm_reset_control_get_optional_shared(dev, "scu");
+ if (IS_ERR(rstc)) {
+ ret = PTR_ERR(rstc);
+ goto rsnd_src_probe_done;
+ }
+
clk = devm_clk_get(dev, name);
if (IS_ERR(clk)) {
ret = PTR_ERR(clk);
@@ -766,7 +823,7 @@ int rsnd_src_probe(struct rsnd_priv *priv)
}

ret = rsnd_mod_init(priv, rsnd_mod_get(src),
- &rsnd_src_ops, clk, NULL, RSND_MOD_SRC, i);
+ &rsnd_src_ops, clk, rstc, RSND_MOD_SRC, i);
if (ret)
goto rsnd_src_probe_done;

--
2.25.1