Please find below a patch against kernel 2.6.5-rc1 to add the pcf8574
driver (an I/O expander for the I2C bus). I have ported it from the 2.4
version, and it includes some fixes and simplifications.

It has been reviewed by Jean Delvare on IRC.

Quoting myself:

> This tends to increase the size of the three set_store_regs_fan_div
> functions, and I am considering refactoring them at some point. Later
> though.

Here is the promised refactoring. Tested on my AS99127F rev.1, seems to
work. As for the previous patch, there is a part that I cannot test with
the AS99127F, so additional testing is welcome.

I agree this makes the code slightly less readable, but this saves 60
lines of code (1754 bytes, around 3% of the driver total), and is
actually far less complex that I first feared.

into ppc970.osdl.org:/home/torvalds/v2.6/linux

into ppc970.osdl.org:/home/torvalds/v2.6/linux

into ppc970.osdl.org:/home/torvalds/v2.6/linux

We no longer have a CPU_OFFLINE notifier: we freeze the machine and
kill the CPU atomically.  Remove it.

Various files keep per-cpu caches which need to be freed/moved when a
CPU goes down.  All under CONFIG_HOTPLUG_CPU ifdefs.

scsi.c: drain dead cpu's scsi_done_q onto this cpu.

buffer.c: brelse the bh_lrus queue for dead cpu.

timer.c: migrate timers from dead cpu, being careful of lock order vs
	__mod_timer.

radix_tree.c: free dead cpu's radix_tree_preloads

page_alloc.c: empty dead cpu's nr_pagecache_local into nr_pagecache, and
	free pages on cpu's local cache.

slab.c: stop reap_timer for dead cpu, adjust each cache's free limit, and
	free each slab cache's per-cpu block.

swap.c: drain dead cpu's lru_add_pvecs into ours, and empty its committed_space
	counter into global counter.

dev.c: drain device queues from dead cpu into this one.

flow.c: drain dead cpu's flow cache.

Keep track of kswapds: it's OK that they get moved off a node when the
last CPU goes down, but when a CPU comes back, we should try to move
the kswapd back onto its node.

Workqueues need to bring up/destroy the per-cpu thread on cpu up/down.

1) Add a global list of workqueues, and keep the name in the structure
   (to name the newly created thread).

2) Remove BUG_ON in run_workqueue, since thread is dragged off CPU when
   it goes down.

3) Lock out cpu up/down in flush_workqueue, create_workqueue and
   destroy_workqueue.

4) Add notifier to add/destroy workqueue threads, and take over work.

Change ksoftirqd not to assume it's on the CPU: when a cpu goes down,
it will be rudely dragged off.  Since do_softirq() uses
smp_processor_id(), it's easiest to disable preemption, check that the
cpu is still up, then call do_softirq().

If the cpu is actually offline, wait for the notifier, which kills us.

Take over tasklets from dead cpu in the notifier.

Clean up redundant double assignment in CPU_UP callback.

Add hook for RCU to handle jobs on dead cpu.  Requires new
tasklet_kill_immediate for RCU to clean up its tasklet (which might
have been about to run, so tasklet_kill won't work).

Change the migration thread to directly use its cpu arg, rather than
smp_processor_id(): if a cpu goes up then down rapidly, it can be on
the wrong cpu just before it is stopped.

Add code to stop the migration thread on CPU_DEAD and CPU_UP_CANCELED.

Remove the (bogus) priority of the notifier.

We need the migration thread to be RT as soon as the CPU comes online:
for example, stop_machine() (another RT task) expects to yield to it.
Extract the core of setscheduler() and do that when the migration
thread is created.  rq lock is a precaution against the (theoretical)
possibility of someone else doing setscheduer on this thread at the
same time.

Currently the migration thread re-enables irqs, then calls
move_task_away which disables IRQs again and actually does the move.
This means there is a race where the migration thread gets preempted,
and the target CPU can go down.

Hold irqs disabled in migration thread across move_task_away(), which
now doesn't need to save flags (the other caller is the hotplug CPU
code, where irqs are also disabled).

Grab cpu lock around sched_migrate_task() and sys_sched_setaffinity().
This is a noop without CONFIG_HOTPLUG_CPU.

The sched_migrate_task may have a performance penalty on NUMA if lots
of exec rebalancing is happening, however this only applies to
CONFIG_NUMA and CONFIG_HOTPLUG_CPU, which noone does at the moment
anyway.

Also, the scheduler in -mm solves the race another way, so this will
vanish then.

Don't move tasks onto offline cpus in load_balance and wake_task (the
latter is caused by a completion run from stop_machine).

Note that cpu_is_offline() is a noop when CONFIG_HOTPLUG_CPU=n.

Add "online" sysfs attribute to cpus to bring them up and down.

Again, only under CONFIG_HOTPLUG_CPU.

Implement cpu_down(): uses stop_machine to freeze the machine, then
uses (arch-specific) __cpu_disable() and migrate_all_tasks().

Whole thing under CONFIG_HOTPLUG_CPU, so doesn't break archs which
don't define that.

From: Nikita Danilov <Nikita@Namesys.COM>

remove_suid() ignores return value of notify_change()->i_op->setattr().
This mean, that even if file system fails to clear suid bit,
generic_file_aio_write_nolock() proceeds with write, which is unsafe.

Actually, even ext2's ->setattr() can fail, when trying to update ACL, for
example.

Attached patch modifies remove_suid() to return result of ->setattr(), and
updates in-tree callers.

From: Stelian Pop <stelian@popies.net>

This patchlet is just a resync with my tree, it only increments the meye
driver version number and makes some small comment changes as suggested by
Randy Dunlap.

From: Andy Whitcroft <andyw@uk.ibm.com>

Whilst looking at the memory overcommit logic I noticed that the pointer to
the documentation from the *_vm_enough_memory calls is incorrect.  Also
that in one instance the routine does not have the expected pointers.

From: Stelian Pop <stelian@popies.net>

This patch removes the usage of __devinit in the srs methods of the sonypi
driver, because those functions are also called from sonypi_pm_callback().

Patch originally from Randy Dunlap.

From: Grant Grundler <grundler@parisc-linux.org>

This patch adds a comment to "Documentation/SubmittingDrivers" about the
importance of adding a Copyright notice in submitted code.

The parisc-linux port has neglected this in the past and I've been slowly
trying to correct that (along with proper GPL header).

While I make it sound like GPL is the "only" acceptable license, I'll leave
it up to lawyers to determine what other appropriate license could be used
for a new driver.

From: Carl Spalletta <ioanamitu@yahoo.com>

Fix a comment bug.

From: Matt Domsch <Matt_Domsch@dell.com>

Split EDD assembly code from setup.S into edd.S.  This will enable it to be
#included into x86-64 too.

From: Matt Domsch <Matt_Domsch@dell.com>

move edd.c from arch/i386/kernel to new dir drivers/firmware.  Fix up
makefiles and Kconfigs.

From: Matt Domsch <Matt_Domsch@dell.com>

Three patches to move the BIOS Enhanced Disk Drive code from i386-specific
locations into more generic locations, which will allow it to be used on
x86-64 as well.

move edd.h from include/asm-i386 to include/linux

From: DHollenbeck <dick@softplc.com>

This patch was needed against a pristine 2.6.4 kernel when compiling with
"gcc 3.4 _very recent_" using the -Os option.

Without this patch, modules would use a non-inline memcmp() and then not
find it in the kernel, causing depmod to complain and some modules not to
load.

From: Tim Schmielau <tim@physik3.uni-rostock.de>

BSD accounting was missed in the conversion from HZ to USER_HZ.  I thought
nobody cared, but apparently there are still users to it.

From: "Randy.Dunlap" <rddunlap@osdl.org>

From: Michael Veeck <michael.veeck@gmx.net>

Remove unnecessary min/max macros and changes calls to use kernel.h macros
instead.

From: "Randy.Dunlap" <rddunlap@osdl.org>

From: Michael Veeck <michael.veeck@gmx.net>

Remove unnecessary min/max macros and changes calls to use kernel.h macros
instead.

From: "Randy.Dunlap" <rddunlap@osdl.org>

From: Michael Veeck <michael.veeck@gmx.net>

Remove unnecessary min/max macros and changes calls to use kernel.h macros
instead.

From: "Randy.Dunlap" <rddunlap@osdl.org>

From: Michael Veeck <michael.veeck@gmx.net>

Patch (against 2.6.3) removes unnecessary min/max macros and changes calls to
use kernel.h macros instead.

From: "Randy.Dunlap" <rddunlap@osdl.org>

This trivial patch fixes the bug #320:

http://bugme.osdl.org/show_bug.cgi?id=320

The additional comment:

http://bugme.osdl.org/show_bug.cgi?id=320#c1

Is wrong, because it will send the command twice.

We only want to see if the command got success, thus is not necessary
to test against < 0 (if the return value is not 1, we got a error).

Note that I'm using the function (bad) style.

From: "Randy.Dunlap" <rddunlap@osdl.org>

Remove the rest of references to smp.tex
Documentation/cpufreq => Documentation/cpu-freq
DocBook/tulip.{pdf,ps,html} => DocBook/tulip-user.{pdf,ps,html}
Bunch of other typos.

From: "Randy.Dunlap" <rddunlap@osdl.org>

From: Luiz Fernando Capitulino <lcapitulino@prefeitura.sp.gov.br>

From: "Randy.Dunlap" <rddunlap@osdl.org>

From: Luiz Fernando Capitulino <lcapitulino@prefeitura.sp.gov.br>

From: Roman Zippel <zippel@linux-m68k.org>

When a boolean choice value has a dependency of 'm' it can be shortly
treated as a tristate symbol.  This fixes this and also add a small
optimization to precompute the value of the module symbol instead of
checking it all the time.

From: Roman Zippel <zippel@linux-m68k.org>

This patch is by Andreas Fester <Andreas.Fester@gmx.de> and saves and
restores various runtime options of qconf.

From: Roman Zippel <zippel@linux-m68k.org>

This disables some debug prints, which are more confusing than helpful for
normal users.