rtc: pcf2127: fix bug when reading alarm registers

stable inclusion
from stable-v5.10.118
commit c39b91fcd5e35b62da3dc649ad4d239ae50389cb
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L686

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c39b91fcd5e35b62da3dc649ad4d239ae50389cb

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

[ Upstream commit 73ce0530 ]

The first bug is that reading the 5 alarm registers results in a read
operation of 20 bytes. The reason is because the destination buffer is
defined as an array of "unsigned int", and we use the sizeof()
operator on this array to define the bulk read count.

The second bug is that the read value is invalid, because we are
indexing the destination buffer as integers (4 bytes), instead of
indexing it as u8.

Changing the destination buffer type to u8 fixes both problems.
Signed-off-by: NHugo Villeneuve <hvilleneuve@dimonoff.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220208162908.3182581-1-hugo@hugovil.comSigned-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/rtc/rtc-pcf2127.c

@@ -366,7 +366,8 @@ static int pcf2127_watchdog_init(struct device *dev, struct pcf2127 *pcf2127)
 static int pcf2127_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
-	unsigned int buf[5], ctrl2;
+	u8 buf[5];
+	unsigned int ctrl2;
 	int ret;
 
 	ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);