[PATCH 4.16 238/272] hwrng: bcm2835 - Handle deferred clock properly

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stefan Wahren <stefan.wahren@xxxxxxxx>

[ Upstream commit 7b4c5d30d0bd2b22c09d4d993a76e0973a873891 ]

In case the probe of the clock is deferred, we would assume it is
optional. This is wrong, so defer the probe of this driver until
the clock is available.

Fixes: 791af4f4907a ("hwrng: bcm2835 - Manage an optional clock")
Signed-off-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
Acked-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/char/hw_random/bcm2835-rng.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/char/hw_random/bcm2835-rng.c
+++ b/drivers/char/hw_random/bcm2835-rng.c
@@ -163,6 +163,8 @@ static int bcm2835_rng_probe(struct plat
 
 	/* Clock is optional on most platforms */
 	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk) && PTR_ERR(priv->clk) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
 
 	priv->rng.name = pdev->name;
 	priv->rng.init = bcm2835_rng_init;