[PATCHv3 00/16] pps: several fixes and improvements

From: Alexander Gordeev
Date: Wed Aug 04 2010 - 17:14:33 EST

This patchset contains several changes that improve an overall
design/performance of PPS subsystem. I'd like these patches to be
merged mainline if no one objects.

Patches 1-3 are bugfixes.
Patches 4-11 are other improvements to PPS subsystem.
Patches 12-14 add kernel consumer support.
Patch 15 adds parallel port PPS client.
Patch 16 adds parallel port PPS generator.

You can find description for my previous patchset (it describes patches
12-16 in more detailed) here: http://lkml.org/lkml/2010/2/24/189

This patchset is tested against the vanilla 2.6.35 kernel. But we are
actually using it on rt-preempt kernel most of the time.
Those who are interested in other versions of the patchset can find
them in my git repository:

There is one problem however: kernel consumer works bad (if enabled)
when CONFIG_NO_HZ is enabled. The reason for this is commit
a092ff0f90cae22b2ac8028ecd2c6f6c1a9e4601. Without it hardpps() is able
to sync to 1us precision in about 10 seconds. With CONFIG_NO_HZ it is
not syncing at all. This only affects patches 12-14, others are ok.

2John Stultz: the problem is not with logarithmic accumulation because
it works good if NTP_INTERVAL_FREQ is set to 2.

v2 -> v3:
* add patches 1-11
* add clear_wait parameter to pps_parport
* add delay parameter to pps_gen_parport
* fix seqlock unlocking
* fix issues pointed out by Rodolfo Giometti:
* move CONFIG_NTP_PPS to drivers/pps/Kconfig
* swap parport client and generator patches
* style and typo fixes
* move patch that adds unified timestamp gathering to be the beginning

v1 -> v2:
* fix issues pointed out by John Stultz:
* style fixes
* add a about the authorship of the original code
* replace timespec with pps_normtime struct where timespec is used
in a wrong way
* fix seqlock usage in hardpps()
* unbind kernel consumer on device removal
* send raw timestamp instead of the last difference to hardpps() which
simplifies the code and is less error-prone
* update comments in the kernel consumer code to match the reality
* split the patch that adds MONOTONIC_RAW timestmaps into two
* other small fixes

Alexander Gordeev (16):
pps: trivial fixes
pps: declare variables where they are used in switch
pps: fix race in PPS_FETCH handler
pps: unify timestamp gathering
pps: access pps device by direct pointer
pps: convert printk/pr_* to dev_*
pps: move idr stuff to pps.c
pps: add async PPS event handler
pps: don't disable interrupts when using spin locks
pps: use BUG_ON for kernel API safety checks
pps: simplify conditions a bit
ntp: add hardpps implementation
pps: capture MONOTONIC_RAW timestamps as well
pps: add kernel consumer support
pps: add parallel port PPS client
pps: add parallel port PPS signal generator

Documentation/ioctl/ioctl-number.txt | 2 +-
drivers/pps/Kconfig | 10 +
drivers/pps/Makefile | 2 +-
drivers/pps/clients/Kconfig | 7 +
drivers/pps/clients/Makefile | 1 +
drivers/pps/clients/pps-ktimer.c | 43 ++--
drivers/pps/clients/pps-ldisc.c | 49 ++--
drivers/pps/clients/pps_parport.c | 244 +++++++++++++++++
drivers/pps/generators/Kconfig | 17 ++
drivers/pps/generators/Makefile | 9 +
drivers/pps/generators/pps_gen_parport.c | 274 +++++++++++++++++++
drivers/pps/kapi.c | 330 +++++++++++-------------
drivers/pps/pps.c | 201 +++++++++++---
include/linux/pps.h | 7 +
include/linux/pps_kernel.h | 64 ++++-
include/linux/serial_core.h | 5 +-
include/linux/time.h | 2 +
include/linux/timex.h | 1 +
include/linux/tty_ldisc.h | 5 +-
kernel/time/ntp.c | 421 ++++++++++++++++++++++++++++-
kernel/time/timekeeping.c | 34 +++
21 files changed, 1419 insertions(+), 309 deletions(-)
create mode 100644 drivers/pps/clients/pps_parport.c
create mode 100644 drivers/pps/generators/Kconfig
create mode 100644 drivers/pps/generators/Makefile
create mode 100644 drivers/pps/generators/pps_gen_parport.c

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