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[ Upstream commit a6f1a4f05970664004a9370459c6799c1b2f2dcf ] 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 <josua@solid-run.com> Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com> Link: https://lore.kernel.org/r/20250825-rtc-irq-v1-1-0133319406a7@solid-run.com Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.