From patchwork Mon Feb 12 20:11:36 2018
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Subject: hwrng: bcm2835: Handle deferred clock properly
From: Stefan Wahren <stefan.wahren@i2se.com>
X-Patchwork-Id: 10214385
Message-Id: <1518466296-30161-1-git-send-email-stefan.wahren@i2se.com>
To: Herbert Xu <herbert@gondor.apana.org.au>, Matt Mackall <mpm@selenic.com>
Cc: Stefan Wahren <stefan.wahren@i2se.com>,
 Florian Fainelli <f.fainelli@gmail.com>, Arnd Bergmann <arnd@arndb.de>,
 Scott Branden <sbranden@broadcom.com>, Jon Mason <jonmason@broadcom.com>, 
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
 Eric Anholt <eric@anholt.net>, 
 bcm-kernel-feedback-list@broadcom.com, linux-crypto@vger.kernel.org, 
 Ray Jui <rjui@broadcom.com>, linux-arm-kernel@lists.infradead.org
Date: Mon, 12 Feb 2018 21:11:36 +0100

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@i2se.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/char/hw_random/bcm2835-rng.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
index 7a84cec..6767d96 100644
--- 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 platform_device *pdev)
 
 	/* 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;