Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752766Ab0KDT0o (ORCPT ); Thu, 4 Nov 2010 15:26:44 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:53629 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751277Ab0KDT0m (ORCPT ); Thu, 4 Nov 2010 15:26:42 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mime-version:content-type :content-disposition:user-agent; b=RPbZ5+k3CjGyvtjgFqxO+glu0yAf4iwY/C/OKqOhBdvHlfKXr03Fn8e41+wHG9qiu1 96gymTr0va73LgYOFZ3QPSzHAH/ciOZr4G+hkM7NSEodVl5yXwj5R4GyEa+h6Puk/gnu Ujmy71zsnRyiJXD0voMNPatPdYNfdY+mjpNUk= Date: Thu, 4 Nov 2010 20:26:34 +0100 From: Richard Cochran To: linux-kernel@vger.kernel.org Cc: linux-api@vger.kernel.org, Alan Cox , Arnd Bergmann , Christoph Lameter , John Stultz , Peter Zijlstra , Thomas Gleixner Subject: [PATCH RFC 0/8] Dynamic clock devices Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2674 Lines: 62 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-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/