On Tue, Jun 11, 2024 at 10:06:39PM -0700, Richard Cochran wrote: > On Tue, Jun 11, 2024 at 05:04:57PM +0200, Csókás, Bence wrote: > > > PCF2127/29/31 is capable of generating an interrupt on every > > second (SI) or minute (MI) change. It signals this through > > the Minute/Second Flag (MSF) as well, which needs to be cleared. > > This is a RFC, and my comment is that a PPS from an RTC is not useful > to the Linux kernel. I think a TCXO-based RTC can be useful to user space to improve holdover performance with NTP/PTP. There already is the RTC_UIE_ON ioctl to enable interrupts and receive them in user space. The advantage of the PPS device over the ioctl would be more accurate timestamping (kernel vs user-space). Should PPS be supported, it would be nice if it worked generally with all drivers that support RTC_UIE_ON. -- Miroslav Lichvar
