linux-kernel - [v2 2/2] rtc: pcf2127: clear these flags TSF1, TSF2 before enabling interrupt generation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed,  2 Dec 2020 11:18:40 +0800
From:   Biwen Li <biwen.li@....nxp.com>
To:     leoyang.li@....com, alexandre.belloni@...tlin.com,
        anson.huang@....com, aisheng.dong@....com
Cc:     linux-kernel@...r.kernel.org, jiafei.pan@....com,
        linux-rtc@...r.kernel.org, Biwen Li <biwen.li@....com>
Subject: [v2 2/2] rtc: pcf2127: clear these flags TSF1, TSF2 before enabling interrupt generation

From: Biwen Li <biwen.li@....com>

Clear these flags TSF1, TSF2 before enabling interrupt generation

Signed-off-by: Biwen Li <biwen.li@....com>
---
Change in v2:
	- clear flag TSF2

 drivers/rtc/rtc-pcf2127.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index a5418b657c50..7e3fc70ac5f9 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -659,7 +659,7 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 
 	/*
 	 * Enable timestamp function and store timestamp of first trigger
-	 * event until TSF1 and TFS2 interrupt flags are cleared.
+	 * event until TSF1 and TSF2 interrupt flags are cleared.
 	 */
 	ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_TS_CTRL,
 				 PCF2127_BIT_TS_CTRL_TSOFF |
@@ -671,6 +671,31 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 		return ret;
 	}
 
+	/*
+	 * Clear TSF1 field of ctrl1 register and TSF2
+	 * field of ctrl2 register to clear interrupt
+	 * before enabling interrupt generation when
+	 * timestamp flag set. Unless the flag TSF1 won't
+	 * be cleared and get the interrupt storm.
+	 */
+	ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
+				 PCF2127_BIT_CTRL1_TSF1,
+				 0);
+	if (ret) {
+		dev_err(dev, "%s:  control and status register 1 (ctrl1) failed, ret = 0x%x\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
+				 PCF2127_BIT_CTRL2_TSF2,
+				 0);
+	if (ret) {
+		dev_err(dev, "%s:  control and status register 2 (ctrl2) failed, ret = 0x%x\n",
+			__func__, ret);
+		return ret;
+	}
+
 	/*
 	 * Enable interrupt generation when TSF1 or TSF2 timestamp flags
 	 * are set. Interrupt signal is an open-drain output and can be
-- 
2.17.1