linux-kernel - [PATCH] rtc: pcf2127: fix watchdog interrupt mask on pcf2131

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>] [day] [month] [year] [list]

Message-ID: <20250902182235.6825-1-bruno.thomsen@gmail.com>
Date: Tue,  2 Sep 2025 20:22:35 +0200
From: Bruno Thomsen <bruno.thomsen@...il.com>
To: linux-rtc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: Hugo Villeneuve <hvilleneuve@...onoff.com>,
	Bruno Thomsen <bruno.thomsen@...il.com>
Subject: [PATCH] rtc: pcf2127: fix watchdog interrupt mask on pcf2131

When using interrupt pin (INT A) as watchdog output all other
interrupt sources need to be disabled to avoid additional
resets. Resulting INT_A_MASK1 value is 55 (0x37).

Signed-off-by: Bruno Thomsen <bruno.thomsen@...il.com>
---
 drivers/rtc/rtc-pcf2127.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index 2e1ac0c42e93..5a39c227203a 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -606,6 +606,21 @@ static int pcf2127_watchdog_init(struct device *dev, struct pcf2127 *pcf2127)
 			set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);
 	}
 
+	/*
+	 * When using interrupt pin (INT A) as watchdog output, only allow
+	 * watchdog interrupt (PCF2131_BIT_INT_WD_CD) and disable (mask) all
+	 * other interrupts.
+	 */
+	if (pcf2127->cfg->type == PCF2131) {
+		ret = regmap_write(pcf2127->regmap,
+				   PCF2131_REG_INT_A_MASK1,
+				   PCF2131_BIT_INT_BLIE |
+				   PCF2131_BIT_INT_BIE |
+				   PCF2131_BIT_INT_AIE |
+				   PCF2131_BIT_INT_SI |
+				   PCF2131_BIT_INT_MI);
+	}
+
 	return devm_watchdog_register_device(dev, &pcf2127->wdd);
 }
 

base-commit: b320789d6883cc00ac78ce83bccbfe7ed58afcf0
-- 
2.51.0