Okay, here is a work in progress, not well tested, but I would like to get some feedback whether the direction is good or not. The first patch introduces clock devices which can appear and disappear like usb devices (and, I suppose, hot plug PCI but I am not too sure that what is offered here would really work in that case). The subsequent patches convert the clock_ and timer_ system calls, one by one. The clock_ syscalls are moved into a new file and they call the older posix functions when needed. The timer_ syscalls stay where they are, in posix-timers.c, since I did not want to change the fairly involved timer management code. Eventually, we could remove the posix clock_* functions for the CLOCK_* ids from posix-timers.c and rework them using the new dynamic clock api. That would leave just the timer code in posix-timers.c, as the file name suggests. I dropped the idea of having user space open a sysfs file in order to get a reference to a clock, since there are no open/release hooks within sysfs for drivers (coincidentally, there has been some talk about this on the lkml recently, but previously Greg KH object to abusing sysfs as a "clockfs"). Instead, since many clocks (hpet, rtc, ptp, ...) will want to offer a custom chardev for special advanced functionality, the dynamic clock layer registers a cdev for the driver, placing its own hooks into the open/release methods. The driver thus needs to access its private data via a standard access method (not just by using fp->private_data). If a driver doesn't want any chardev functions, that is okay, too. Well, please take a look and let me know what you think. Thanks, Richard Richard Cochran (8): Introduce dynamic clock devices clock device: convert clock_gettime clock device: convert clock_getres clock device: convert clock_settime clock device: convert timer_create clock device: convert timer_delete clock device: convert timer_gettime clock device: convert timer_settime include/linux/clockdevice.h | 117 +++++++++++++++ include/linux/posix-timers.h | 23 +++- include/linux/time.h | 2 + kernel/posix-timers.c | 51 +++++-- kernel/time/Makefile | 3 +- kernel/time/clockdevice.c | 336 ++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 518 insertions(+), 14 deletions(-) create mode 100644 include/linux/clockdevice.h create mode 100644 kernel/time/clockdevice.c -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
