[PATCH 4/4] rng: msm: keep core clock disabled when PRNG not in use

[Sam Day]

This is how the kernel does it. APQ8016E TRM also states that this clock
can be turned off when no random numbers are needed.

Signed-off-by: Sam Day <me at samcday.com>
---
 drivers/rng/msm_rng.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/rng/msm_rng.c b/drivers/rng/msm_rng.c
index 01505509103f28f7c91dd47edb83c23359163c82..aab602c5ed0bfed8b7cb9593fe22a8cef8f0f61a 100644
--- a/drivers/rng/msm_rng.c
+++ b/drivers/rng/msm_rng.c
@@ -44,6 +44,11 @@ static int msm_rng_read(struct udevice *dev, void *data, size_t len)
 	u32 *retdata = data;
 	size_t maxsize;
 	u32 val;
+	int ret;
+
+	ret = clk_enable(&priv->clk);
+	if (ret < 0)
+		return ret;
 
 	/* calculate max size bytes to transfer back to caller */
 	maxsize = min_t(size_t, MAX_HW_FIFO_SIZE, len);
@@ -66,6 +71,8 @@ static int msm_rng_read(struct udevice *dev, void *data, size_t len)
 			break;
 	} while (currsize < maxsize);
 
+	clk_disable(&priv->clk);
+
 	return 0;
 }
 
@@ -118,7 +125,9 @@ static int msm_rng_probe(struct udevice *dev)
 	if (ret < 0)
 		return ret;
 
-	return msm_rng_enable(priv, 1);
+	ret = msm_rng_enable(priv, 1);
+	clk_disable(&priv->clk);
+	return ret;
 }
 
 static int msm_rng_remove(struct udevice *dev)

-- 
2.47.1