From: Josua Mayer Date: Mon, 25 Aug 2025 17:54:09 +0000 (+0200) Subject: rtc: pcf2127: clear minute/second interrupt X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a6f1a4f05970664004a9370459c6799c1b2f2dcf;p=users%2Fhch%2Fmisc.git rtc: pcf2127: clear minute/second interrupt PCF2127 can generate interrupt every full second or minute configured from control and status register 1, bits MI (1) and SI (0). On interrupt control register 2 bit MSF (7) is set and must be cleared to continue normal operation. While the driver never enables this interrupt on its own, users or firmware may do so - e.g. as an easy way to test the interrupt. Add preprocessor definition for MSF bit and include it in the irq bitmask to ensure minute and second interrupts are cleared when fired. This fixes an issue where the rtc enters a test mode and becomes unresponsive after a second interrupt has fired and is not cleared in time. In this state register writes to control registers have no effect and the interrupt line is kept asserted [1]: [1] userspace commands to put rtc into unresponsive state: $ i2cget -f -y 2 0x51 0x00 0x04 $ i2cset -f -y 2 0x51 0x00 0x05 # set bit 0 SI $ i2cget -f -y 2 0x51 0x00 0x84 # bit 8 EXT_TEST set $ i2cset -f -y 2 0x51 0x00 0x05 # try overwrite control register $ i2cget -f -y 2 0x51 0x00 0x84 # no change Signed-off-by: Josua Mayer Reviewed-by: Bruno Thomsen Link: https://lore.kernel.org/r/20250825-rtc-irq-v1-1-0133319406a7@solid-run.com Signed-off-by: Alexandre Belloni --- diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c index 2e1ac0c42e93..3ba1de30e89c 100644 --- a/drivers/rtc/rtc-pcf2127.c +++ b/drivers/rtc/rtc-pcf2127.c @@ -42,6 +42,7 @@ #define PCF2127_BIT_CTRL2_AF BIT(4) #define PCF2127_BIT_CTRL2_TSF2 BIT(5) #define PCF2127_BIT_CTRL2_WDTF BIT(6) +#define PCF2127_BIT_CTRL2_MSF BIT(7) /* Control register 3 */ #define PCF2127_REG_CTRL3 0x02 #define PCF2127_BIT_CTRL3_BLIE BIT(0) @@ -96,7 +97,8 @@ #define PCF2127_CTRL2_IRQ_MASK ( \ PCF2127_BIT_CTRL2_AF | \ PCF2127_BIT_CTRL2_WDTF | \ - PCF2127_BIT_CTRL2_TSF2) + PCF2127_BIT_CTRL2_TSF2 | \ + PCF2127_BIT_CTRL2_MSF) #define PCF2127_MAX_TS_SUPPORTED 4