[PATCH 1/4] ASoC: renesas: msiof: msiof_update_and_wait() checks whether reg was updated

[Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>]

msiof_update_and_wait() updates reg and waits until the value was updated.
But, if the set value was same as current reg value, no update will be
happen. Check the value, and ignore waiting if no update.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
---
 sound/soc/renesas/rcar/msiof.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/sound/soc/renesas/rcar/msiof.c b/sound/soc/renesas/rcar/msiof.c
index 36d31ab8ac6a..b7633ed3e3f0 100644
--- a/sound/soc/renesas/rcar/msiof.c
+++ b/sound/soc/renesas/rcar/msiof.c
@@ -82,13 +82,18 @@ struct msiof_priv {
 #define msiof_write(priv, reg, val)	iowrite32(val, (priv)->base + reg)
 #define msiof_status_clear(priv)	msiof_write(priv, SISTR, SISTR_ERR)
 
-static void msiof_update(struct msiof_priv *priv, u32 reg, u32 mask, u32 val)
+static int msiof_update(struct msiof_priv *priv, u32 reg, u32 mask, u32 val)
 {
 	u32 old = msiof_read(priv, reg);
 	u32 new = (old & ~mask) | (val & mask);
+	int updated = false;
 
-	if (old != new)
+	if (old != new) {
 		msiof_write(priv, reg, new);
+		updated = true;
+	}
+
+	return updated;
 }
 
 static void msiof_update_and_wait(struct msiof_priv *priv, u32 reg, u32 mask, u32 val, u32 expect)
@@ -96,7 +101,9 @@ static void msiof_update_and_wait(struct msiof_priv *priv, u32 reg, u32 mask, u3
 	u32 data;
 	int ret;
 
-	msiof_update(priv, reg, mask, val);
+	ret = msiof_update(priv, reg, mask, val);
+	if (!ret) /* no update */
+		return;
 
 	ret = readl_poll_timeout_atomic(priv->base + reg, data,
 					(data & mask) == expect, 1, 128);
-- 
2.43.0