From: Alexandre Belloni <alexandre.belloni@bootlin.com>
Date: Mon, 12 Feb 2018 22:47:18 +0000 (+0100)
Subject: rtc: nvmem: disallow registering nvmem more than once
X-Git-Tag: v4.17-rc1~62^2~120
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=ab3ea36eda76069ba52e9b6aef5a9370b0b462bf;p=linux-block.git

rtc: nvmem: disallow registering nvmem more than once

Make rtc_nvmem_register return -EBUSY when an nvmem is already registered
for that RTC.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---

diff --git a/drivers/rtc/nvmem.c b/drivers/rtc/nvmem.c
index 293df6db7c42..fd1c39a5ade5 100644
--- a/drivers/rtc/nvmem.c
+++ b/drivers/rtc/nvmem.c
@@ -87,6 +87,9 @@ static void rtc_nvram_unregister(struct rtc_device *rtc)
 int rtc_nvmem_register(struct rtc_device *rtc,
 		       struct nvmem_config *nvmem_config)
 {
+	if (!IS_ERR_OR_NULL(rtc->nvmem))
+		return -EBUSY;
+
 	if (!nvmem_config)
 		return -ENODEV;