From 408cc6eb1e3adc43a434d5d584708c2a1d2c6c32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= <mirq-linux@rere.qmqm.pl>
Date: Thu, 17 Aug 2017 15:56:11 +0200
Subject: [PATCH] iio: magnetometer: ak8974: add_device_randomness (serial
 number)
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Mix device-specific data into randomness pool.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/magnetometer/ak8974.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
index 76091da20a0c..b1c209faf1b1 100644
--- a/drivers/iio/magnetometer/ak8974.c
+++ b/drivers/iio/magnetometer/ak8974.c
@@ -20,6 +20,7 @@
 #include <linux/mutex.h>
 #include <linux/delay.h>
 #include <linux/bitops.h>
+#include <linux/random.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/pm_runtime.h>
@@ -470,6 +471,7 @@ static int ak8974_detect(struct ak8974 *ak8974)
 		ret = ak8974_get_u16_val(ak8974, AMI305_SN, &sn);
 		if (ret)
 			return ret;
+		add_device_randomness(&sn, sizeof(sn));
 		dev_info(&ak8974->i2c->dev,
 			 "detected %s, FW ver %02x, S/N: %04x\n",
 			 name, fw, sn);