From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Biwen Li <biwen.li@nxp.com>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Sasha Levin <sashal@kernel.org>,
linux-rtc@vger.kernel.org
Subject: [PATCH AUTOSEL 5.2 20/42] rtc: pcf85363/pcf85263: fix regmap error in set_time
Date: Sun, 29 Sep 2019 13:32:19 -0400 [thread overview]
Message-ID: <20190929173244.8918-20-sashal@kernel.org> (raw)
In-Reply-To: <20190929173244.8918-1-sashal@kernel.org>
From: Biwen Li <biwen.li@nxp.com>
[ Upstream commit 7ef66122bdb3b839e9f51b76d7e600b6e21ef648 ]
Issue:
- # hwclock -w
hwclock: RTC_SET_TIME: Invalid argument
Why:
- Relative commit: 8b9f9d4dc511 ("regmap: verify if register is
writeable before writing operations"), this patch
will always check for unwritable registers, it will compare reg
with max_register in regmap_writeable.
- The pcf85363/pcf85263 has the capability of address wrapping
which means if you access an address outside the allowed range
(0x00-0x2f) hardware actually wraps the access to a lower address.
The rtc-pcf85363 driver will use this feature to configure the time
and execute 2 actions in the same i2c write operation (stopping the
clock and configure the time). However the driver has also
configured the `regmap maxregister` protection mechanism that will
block accessing addresses outside valid range (0x00-0x2f).
How:
- Split of writing regs to two parts, first part writes control
registers about stop_enable and resets, second part writes
RTC time and date registers.
Signed-off-by: Biwen Li <biwen.li@nxp.com>
Link: https://lore.kernel.org/r/20190829021418.4607-1-biwen.li@nxp.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/rtc/rtc-pcf85363.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/rtc/rtc-pcf85363.c b/drivers/rtc/rtc-pcf85363.c
index a075e77617dcb..3450d615974d5 100644
--- a/drivers/rtc/rtc-pcf85363.c
+++ b/drivers/rtc/rtc-pcf85363.c
@@ -166,7 +166,12 @@ static int pcf85363_rtc_set_time(struct device *dev, struct rtc_time *tm)
buf[DT_YEARS] = bin2bcd(tm->tm_year % 100);
ret = regmap_bulk_write(pcf85363->regmap, CTRL_STOP_EN,
- tmp, sizeof(tmp));
+ tmp, 2);
+ if (ret)
+ return ret;
+
+ ret = regmap_bulk_write(pcf85363->regmap, DT_100THS,
+ buf, sizeof(tmp) - 2);
if (ret)
return ret;
--
2.20.1
prev parent reply other threads:[~2019-09-29 17:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190929173244.8918-1-sashal@kernel.org>
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 19/42] rtc: snvs: fix possible race condition Sasha Levin
2019-09-29 17:32 ` Sasha Levin [this message]
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