[PATCH v4 09/10] ASoC: renesas: fsi: add fsi_clk_prepare/unprepare()

[phucduc.bui@gmail.com]

From: bui duc phuc <phucduc.bui@gmail.com>

Add fsi_clk_prepare() and fsi_clk_unprepare() helpers and call them
from fsi_dai_startup() and fsi_dai_shutdown().
This ensures clk_prepare() and clk_unprepare() are executed from
sleepable contexts and keeps clocks prepared only while audio streams
are active.

Suggested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
---

Changes in v4:
 - Move clock->count early return check to the beginning of 
   fsi_clk_[un]prepare() to simplify the code.

 sound/soc/renesas/fsi.c | 77 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 76 insertions(+), 1 deletion(-)

diff --git a/sound/soc/renesas/fsi.c b/sound/soc/renesas/fsi.c
index 3f303e15e835..6537321242c0 100644
--- a/sound/soc/renesas/fsi.c
+++ b/sound/soc/renesas/fsi.c
@@ -294,6 +294,7 @@ struct fsi_master {
 	struct fsi_priv fsib;
 	struct clk *clk_spu;
 	const struct fsi_core *core;
+	int spu_count;
 	spinlock_t lock;
 };
 
@@ -730,6 +731,78 @@ static int fsi_clk_is_valid(struct fsi_priv *fsi)
 		fsi->clock.rate;
 }
 
+static int fsi_clk_prepare(struct fsi_priv *fsi)
+{
+	struct fsi_clk *clock = &fsi->clock;
+	struct clk *spu = fsi->master->clk_spu;
+	struct clk *xck = clock->xck;
+	struct clk *ick = clock->ick;
+	struct clk *div = clock->div;
+	int ret;
+
+	if (clock->count != 0)
+		return 0;
+
+	if (!IS_ERR_OR_NULL(spu) && fsi->master->spu_count == 0) {
+		ret = clk_prepare(spu);
+		if (ret)
+			return ret;
+	}
+
+	if (!IS_ERR_OR_NULL(xck)) {
+		ret = clk_prepare(xck);
+		if (ret)
+			goto err_spu;
+	}
+
+	if (!IS_ERR_OR_NULL(ick)) {
+		ret = clk_prepare(ick);
+		if (ret)
+			goto err_xck;
+	}
+
+	if (!IS_ERR_OR_NULL(div)) {
+		ret = clk_prepare(div);
+		if (ret)
+			goto err_ick;
+	}
+
+	return 0;
+
+err_ick:
+	clk_unprepare(ick);
+err_xck:
+	clk_unprepare(xck);
+err_spu:
+	clk_unprepare(spu);
+
+	return ret;
+}
+
+static void fsi_clk_unprepare(struct fsi_priv *fsi)
+{
+	struct fsi_clk *clock = &fsi->clock;
+	struct clk *spu = fsi->master->clk_spu;
+	struct clk *xck = clock->xck;
+	struct clk *ick = clock->ick;
+	struct clk *div = clock->div;
+
+	if (clock->count != 0)
+		return;
+
+	if (!IS_ERR_OR_NULL(div))
+		clk_unprepare(div);
+
+	if (!IS_ERR_OR_NULL(ick))
+		clk_unprepare(ick);
+
+	if (!IS_ERR_OR_NULL(xck))
+		clk_unprepare(xck);
+
+	if (!IS_ERR_OR_NULL(spu) && fsi->master->spu_count == 0)
+		clk_unprepare(spu);
+}
+
 static int fsi_clk_enable(struct device *dev,
 			  struct fsi_priv *fsi)
 {
@@ -1580,7 +1653,7 @@ static int fsi_dai_startup(struct snd_pcm_substream *substream,
 
 	fsi_clk_invalid(fsi);
 
-	return 0;
+	return fsi_clk_prepare(fsi);
 }
 
 static void fsi_dai_shutdown(struct snd_pcm_substream *substream,
@@ -1588,6 +1661,7 @@ static void fsi_dai_shutdown(struct snd_pcm_substream *substream,
 {
 	struct fsi_priv *fsi = fsi_get_priv(substream);
 
+	fsi_clk_unprepare(fsi);
 	fsi_clk_invalid(fsi);
 }
 
@@ -1975,6 +2049,7 @@ static int fsi_probe(struct platform_device *pdev)
 
 	/* master setting */
 	master->core		= core;
+	master->spu_count	= 0;
 	spin_lock_init(&master->lock);
 
 	/* FSI A setting */
-- 
2.43.0