Sometimes it is necessary to know how the state is,
and it is easier to query rfkill than keep track of
it somewhere else, so add a function for that. This
could later be expanded to return hard/soft block,
but so far that isn't necessary.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The new code added by this patch will make rfkill create
a misc character device /dev/rfkill that userspace can use
to control rfkill soft blocks and get status of devices as
well as events when the status changes.

Using it is very simple -- when you open it you can read
a number of times to get the initial state, and every
further read blocks (you can poll) on getting the next
event from the kernel. The same structure you read is
also used when writing to it to change the soft block of
a given device, all devices of a given type, or all
devices.

This also makes CONFIG_RFKILL_INPUT selectable again in
order to be able to test without it present since its
functionality can now be replaced by userspace entirely
and distros and users may not want the input part of
rfkill interfering with their userspace code. We will
also write a userspace daemon to handle all that and
consequently add the input code to the feature removal
schedule.

In order to have rfkilld support both kernels with and
without CONFIG_RFKILL_INPUT (or new kernels after its
eventual removal) we also add an ioctl (that only exists
if rfkill-input is present) to disable rfkill-input.
It is not very efficient, but at least gives the correct
behaviour in all cases.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This patch completely rewrites the rfkill core to address
the following deficiencies:

 * all rfkill drivers need to implement polling where necessary
   rather than having one central implementation

 * updating the rfkill state cannot be done from arbitrary
   contexts, forcing drivers to use schedule_work and requiring
   lots of code

 * rfkill drivers need to keep track of soft/hard blocked
   internally -- the core should do this

 * the rfkill API has many unexpected quirks, for example being
   asymmetric wrt. alloc/free and register/unregister

 * rfkill can call back into a driver from within a function the
   driver called -- this is prone to deadlocks and generally
   should be avoided

 * rfkill-input pointlessly is a separate module

 * drivers need to #ifdef rfkill functions (unless they want to
   depend on or select RFKILL) -- rfkill should provide inlines
   that do nothing if it isn't compiled in

 * the rfkill structure is not opaque -- drivers need to initialise
   it correctly (lots of sanity checking code required) -- instead
   force drivers to pass the right variables to rfkill_alloc()

 * the documentation is hard to read because it always assumes the
   reader is completely clueless and contains way TOO MANY CAPS

 * the rfkill code needlessly uses a lot of locks and atomic
   operations in locked sections

 * fix LED trigger to actually change the LED when the radio state
   changes -- this wasn't done before
Tested-by: NAlan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br> [thinkpad]
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

net/rfkill/rfkill.c: In function 'update_rfkill_state':
net/rfkill/rfkill.c:99: error: implicit declaration of function 'rfkill_led_trigger'

Caused by

: commit 492301fb
: Author: Larry Finger <Larry.Finger@lwfinger.net>
: Date:   Thu Apr 9 22:14:19 2009 -0500
:
:     rfkill: Fix broken rfkill LED in 2.6.30-rc1

Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Michael Buesch <mb@bu3sch.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The rfkill system fails to issue a LED trigger event when the rfkill state
changes.
Signed-off-by: NLarry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

There's a lot of rfkill-input code that cannot ever be
compiled and is useless until somebody needs and tests
it -- therefore remove it.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Almost all drivers do not support user_claim, so remove it
completely and always report -EOPNOTSUPP to userspace. Since
userspace cannot really drive rfkill _anyway_ (due to the
odd restrictions imposed by the documentation) having this
code is just pointless.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

commit 4dec9b80 ("rfkill: strip pointless
notifier chain") removed the only user of rfkill_led_trigger() that was not
guarded by #ifdef CONFIG_RFKILL_LEDS. Therefore, move rfkill_led_trigger()
completely inside #ifdef CONFIG_RFKILL_LEDS and avoid the compile time
warning:

net/rfkill/rfkill.c:59: warning: 'rfkill_led_trigger' defined but not used
Signed-off-by: NSimon Holm Thøgersen <odie@cs.aau.dk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

No users, so no reason to have it.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

We "optimize" away the get_state() hook call on rfkill_toggle_radio
when doing a forced state change.  This means the resume path is not
calling get_state() as it should.

Call it manually on the resume handler, as we don't want to mess with
the EPO path by removing the optimization.  This has the added benefit
of making it explicit that rfkill->state could have been modified
before we hit the rfkill_toggle_radio() call in the class resume
handler.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The rfkill class API requires that the driver connected to a class
call rfkill_force_state() on resume to update the real state of the
rfkill controller, OR that it provides a get_state() hook.

This means there is potentially a hidden call in the resume code flow
that changes rfkill->state (i.e. rfkill_force_state()), so the
previous state of the transmitter was being lost.

The simplest and most future-proof way to fix this is to explicitly
store the pre-sleep state on the rfkill structure, and restore from
that on resume.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

> I'll have a prod at why the [hso] rfkill stuff isn't working next

Ok, I believe this is due to the addition of rfkill_check_duplicity in
rfkill and the fact that test_bit actually returns a negative value
rather than the postive one expected (which is of course equally true).
So when the second WLAN device (the hso device, with the EEE PC WLAN
being the first) comes along rfkill_check_duplicity returns a negative
value and so rfkill_register returns an error. Patch below fixes this
for me.
Signed-Off-By: NJonathan McDowell <noodles@earth.li>
Acked-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Limit the number of "expensive" rfkill workqueue operations per second, in
order to not hog system resources too much when faced with a rogue source
of rfkill input events.

The old rfkill-input code (before it was refactored) had such a limit in
place.  It used to drop new events that were past the rate limit.  This
behaviour was not implemented as an anti-DoS measure, but rather as an
attempt to work around deficiencies in input device drivers which would
issue multiple KEY_FOO events too soon for a given key FOO (i.e. ones that
do not implement mechanical debouncing properly).

However, we can't really expect such issues to be worked around by every
input handler out there, and also by every userspace client of input
devices.  It is the input device driver's responsability to do debouncing
instead of spamming the input layer with bogus events.

The new limiter code is focused only on anti-DoS behaviour, and tries to
not lose events (instead, it coalesces them when possible).

The transmitters are updated once every 200ms, maximum.  Care is taken not
to delay a request to _enter_ rfkill transmitter Emergency Power Off (EPO)
mode.

If mistriggered (e.g. by a jiffies counter wrap), the code delays processing
*once* by 200ms.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

rfkill_resume() would always restore the rfkill controller state to its
pre-suspend state.

Now that we know when we are under EPO, kick the rfkill controller to
SOFT_BLOCKED state instead of to its pre-suspend state when it is resumed
while EPO mode is active.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Add of software-based sanity to rfkill and rfkill-input so that it can
reproduce what hardware-based EPO switches do, blocking all transmitters
and locking down any further attempts to unblock them until the switch is
deactivated.

rfkill-input is responsible for issuing the EPO control requests, like
before.

While an rfkill EPO is active, all transmitters are locked to one of the
BLOCKED states and all attempts to change that through the rfkill API
(userspace and kernel) will be either ignored or return -EPERM errors.

The lock will be released upon receipt of EV_SW SW_RFKILL_ALL ON by
rfkill-input, or should modular rfkill-input be unloaded.

This makes rfkill and rfkill-input extend the operation of an existing
wireless master kill switch to all wireless devices in the system, even
those that are not under hardware or firmware control.

Since the above is the expected operational behavior for the master rfkill
switch, the EPO lock functionality is not optional.

Also, extend rfkill-input to allow for three different behaviors when it
receives an EV_SW SW_RFKILL_ALL ON input event.  The user can set which
behavior he wants through the master_switch_mode parameter:

master_switch_mode = 0: EV_SW SW_RFKILL_ALL ON just unlocks rfkill
controller state changes (so that the rfkill userspace and kernel APIs can
now be used to change rfkill controller states again), but doesn't change
any of their states (so they will all remain blocked).  This is the safest
mode of operation, as it requires explicit operator action to re-enable a
transmitter.

master_switch_mode = 1: EV_SW SW_RFKILL_ALL ON causes rfkill-input to
attempt to restore the system to the state before the last EV_SW
SW_RFKILL_ALL OFF event, or to the default global states if no EV_SW
SW_RFKILL_ALL OFF ever happened.   This is the recommended mode of
operation for laptops.

master_switch_mode = 2: tries to unblock all rfkill controllers (i.e.
enable all transmitters) when an EV_SW SW_RFKILL_ALL ON event is received.
This is the default mode of operation, as it mimics the previous behavior
of rfkill-input.

In order to implement these features in a clean way, the entire event
handling of rfkill-input was refactored into a single worker function.

Protection against input event DoS (repeatedly firing rfkill events for
rfkill-input to process) was removed during the code refactoring.  It will
be added back in a future patch.

Note that with these changes, rfkill-input doesn't need to explicitly
handle any radio types for which KEY_<radio type> or SW_<radio type> events
do not exist yet.

Code to handle EV_SW SW_{WLAN,WWAN,BLUETOOTH,WIMAX,...} was added as it
might be needed in the future (and its implementation is not that obvious),
but is currently #ifdef'd out to avoid wasting resources.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Export the the global switch states to rfkill-input.  This is needed to
properly implement KEY_* handling without disregarding the initial state.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Apparently, many applications don't expect to get EAGAIN from fd read/write
operations, since POSIX doesn't mandate it.

Use mutex_lock_killable instead of mutex_lock_interruptible, which won't
cause issues.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Initialise correctly last fields, so tasks can be actually executed.
On some architectures the initial jiffies value is not zero, so later
all rfkill incorrectly decides that rfkill_*.last is in future.
Signed-off-by: NDmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

For some m68k configs, I get:

| net/rfkill/rfkill-input.c: In function 'rfkill_start':
| net/rfkill/rfkill-input.c:208: error: dereferencing pointer to incomplete type

As the incomplete type is `struct task_struct', including <linux/sched.h> fixes
it.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The LED state was not being updated by rfkill_force_state(), which
will cause regressions in wireless drivers that had old-style rfkill
support and are updated to use rfkill_force_state().

The LED state was not being updated when a change was detected through
the rfkill->get_state() hook, either.

Move the LED trigger update calls into notify_rfkill_state_change(),
where it should have been in the first place.  This takes care of both
issues above.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Currently, rfkill would stand in the way of properly supporting wireless
devices that are capable of waking the system up from sleep or hibernation
when they receive a special wireless message.  It would also get in the way
of mesh devices that need to remain operational even during platform
suspend.

To avoid that, stop trying to block the transmitters on the rfkill class
suspend handler.

Drivers that need rfkill's older behaviour will have to implement it by
themselves in their own suspend handling.

Do note that rfkill *will* attempt to restore the transmitter state on
resume in any situation.  This happens after the driver's resume method is
called by the suspend core (class devices resume after the devices they are
attached to have been resumed).

The following drivers need to check if they need to explicitly block
their transmitters in their own suspend handlers (maintainers Cc'd):
	arch/arm/mach-pxa/tosa-bt.c
	drivers/net/usb/hso.c
	drivers/net/wireless/rt2x00/* (USB might need it?)
	drivers/net/wireless/b43/ (SSB over USB might need it?)
	drivers/misc/hp-wmi.c
	eeepc-laptop w/rfkill support (not in mainline yet)
	Compal laptop w/rfkill support (not in mainline yet)
	toshiba-acpi w/rfkill support (not in mainline yet)
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Andrew Bird <ajb@spheresystems.co.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Cezary Jackiewicz <cezary.jackiewicz@gmail.com>
Cc: Philip Langdale <philipl@overt.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

rfkill_mutex and rfkill->mutex are too easy to confuse with each other.

Rename rfkill_mutex to rfkill_global_mutex, so that they are easier to tell
apart with just one glance.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Michael Buesch <mb@bu3sch.de>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

BUG_ON() and WARN() the heck out of buggy drivers calling into the rfkill
subsystem.

Also switch from WARN_ON(1) to the new descriptive WARN().
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Trivial patch adding a missing line break on
rfkill_claim_show().
Signed-off-by: NFelipe Balbi <felipe.balbi@nokia.com>
Acked-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.co>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Switch sysfs parsing to something that actually works properly.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Trivial patch adding a missing line break on
rfkill_claim_show().
Signed-off-by: NFelipe Balbi <felipe.balbi@nokia.com>
Acked-by: NIvo van Doorn <IvDoorn@gmail.co>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

While it is interesting to not add last-enum-markers because it allows gcc
to warn us of switch() statements missing a valid state, we really should
be handling memory corruption on a rfkill state with default clauses,
anyway.

So add RFKILL_STATE_MAX and use it where applicable.  It makes for safer
code in the long run.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

rfkill is not a small, mere detail in wireless support.  Once it starts
supporting rfkill and users start counting on that support, a wireless
device is at risk of operating in dangerous conditions should rfkill
support fail to properly activate.

Therefore, add the required __must_check annotations on some key functions
of the rfkill API, for which the wireless drivers absolutely MUST handle
the failure mode safely in order to avoid a potentially dangerous situation
where the wireless transmitter is left enabled when the user don't want it
to.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Add a second set of global states, "rfkill_default_states", to track the
state that will be used when the first rfkill class of a given type is
registered, and also to save "undo" information when rfkill_epo is called.

Add a new exported function, rfkill_set_default(), which can be used by
platform drivers to restore radio state saved by the platform across
reboots or shutdown.

Also, fix rfkill_epo to properly update rfkill_states, but still preserve a
copy of the state so that we can undo the effect of rfkill_epo later if we
want to.  Add rfkill_restore_states() to restore rfkill_states from the
copy.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Detect and abort with -EEXIST if rfkill_register is called twice on the
same rfkill struct.  And WARN_ON(it) for good measure.

While at it, flag when we are adding the first switch of a type, we will
need that information later.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Guard rfkill controllers attached to a rfkill class against state changes
after class suspend has been issued.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Provide default activate function to set the state of the led
when the led becomes bound to the trigger
Signed-off-by: NDmitry Baryshkov <dbaryshkov@gmail.com>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Acked-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Allow the rfkill driver to specify led trigger name.
By default it still defaults to the name of rfkill switch.
Signed-off-by: NDmitry Baryshkov <dbaryshkov@gmail.com>
Acked-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Every time a new input device that is capable of one of the
rfkill EV_SW events (currently only SW_RFKILL_ALL) is connected to
rfkill-input, we must check the states of the input EV_SW switches
and take action.  Otherwise, we will ignore the initial switch state.

We also need to re-check the states of the EV_SW switches after
a device that was under an exclusive grab is released back to us,
since we got no input events from that device while it was grabbed.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

For some stupid reason, I sent and old version of the patch minor kernel
doc-fix patch, and it got merged before I noticed the problem. This is an
incremental fix on top.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

There are two mutexes in rfkill:

rfkill->mutex, which protects some of the fields of a rfkill struct, and is
also used for callback serialization.

rfkill_mutex, which protects the global state, the list of registered
rfkill structs and rfkill->claim.

Make sure to use the correct mutex, and to not miss locking rfkill->mutex
even when we already took rfkill_mutex.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

rfkill needs to unregister the led trigger AFTER a call to
rfkill_remove_switch(), otherwise it will not update the LED state,
possibly leaving it ON when it should be OFF.

To make led-trigger unregistering safer, guard against unregistering a
trigger twice, and also against issuing trigger events to a led trigger
that was unregistered.  This makes the error unwind paths more resilient.

Refer to "rfkill: Register LED triggers before registering switch".
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Michael Buesch <mb@bu3sch.de>
Cc: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

While the rfkill class does work with just get_state(), it doesn't work
well on devices that are subject to external events that cause rfkill state
changes.

Document that rfkill_force_state() is required in those cases.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

rfkill_add_switch() calls rfkill_toggle_radio() to set the state of a
recently registered rfkill class to the current global state [for that
rfkill->type].

The rfkill_toggle_radio() call is going to error out if the hardware is
RFKILL_STATE_HARD_BLOCKED, and the global state is RFKILL_STATE_UNBLOCKED.

That is a quite normal situation which I missed to account for.  As things
stand, the error return from rfkill_toggle_radio ends up causing
rfkill_register to bail out with an error (de-registering the new switch in
the process), which is Not Nice.

Change rfkill_add_switch() to not return errors because of a failed call to
rfkill_toggle_radio().  We can go back to returning errors again (if that's
indeed the right thing to do) if we define the exact error codes the
rfkill->toggle_radio callbacks are to return in each situation, so that we
can ignore the right ones only.

Bug reported by "kionez <kionez@anche.no>".
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: kionez <kionez@anche.no>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>