There are several drivers that use LEDs and depend on exactly the same
device tree binding. However, the binding documentation has simply been
cut-and-paste into each of the binding documents. Rather than continue
to duplicate it, this patch adds a common led binding document that all
can reference.
Signed-off-by: NMarek Belisko <marek.belisko@open-nandra.com>
Reviewed-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Path to gpio.txt (dt) document was broken.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Trivial fix
Signed-off-by: NMarek Vasut <marex@denx.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linux-doc@vger.kernel.org
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

The gpios property is described in Documentation/devicetree/gpio.txt, so
reference this document.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

There are numerous broken references to Documentation files (in other
Documentation files, in comments, etc.). These broken references are
caused by typo's in the references, and by renames or removals of the
Documentation files. Some broken references are simply odd.

Fix these broken references, sometimes by dropping the irrelevant text
they were part of.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

The device tree is used by more than just PowerPC.  Make the documentation
directory available to all.

v2: reorganized files while moving to create arch and driver specific
    directories.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NJosh Boyer <jwboyer@linux.vnet.ibm.com>

There already is a "default-on" trigger but there are problems with it.

For one, it's a inefficient way to do it and requires led trigger support
to be compiled in.

But the real reason is that is produces a glitch on the LED.  The GPIO is
allocate with the LED *off*, then *later* when the trigger runs it is
turned back on.  If the LED was already on via the GPIO's reset default or
action of the firmware, this produces a glitch where the LED goes from on
to off to on.  While normally this is fast enough that it wouldn't be
noticeable to a human observer, there are still serious problems.

One is that there may be something else on the GPIO line, like a hardware
alarm or watchdog, that is fast enough to notice the glitch.

Another is that the kernel may panic before the LED is turned back on, thus
hanging with the LED in the wrong state.  This is not just speculation, but
actually happened to me with an embedded system that has an LED which
should turn off when the kernel finishes booting, which was left in the
incorrect state due to a bug in the OF LED binding code.

We also let GPIO LEDs get their initial value from whatever the current
state of the GPIO line is.  On some systems the LEDs are put into some
state by the firmware or hardware before Linux boots, and it is desired to
have them keep this state which is otherwise unknown to Linux.

This requires that the underlying GPIO driver support reading the value of
output GPIOs.  Some drivers support this and some do not.

The platform device binding gains a field in the platform data
"default_state" that controls this.  There are three constants defined to
select from on, off, or keeping the current state.  The OpenFirmware
binding uses a property named "default-state" that can be set to "on",
"off", or "keep".  The default if the property isn't present is off.
Signed-off-by: NTrent Piepho <xyzzy@speakeasy.org>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>
Acked-by: NSean MacLennan <smaclennan@pikatech.com>
Signed-off-by: NRichard Purdie <rpurdie@linux.intel.com>

Add bindings to support LEDs defined as of_platform devices in addition to
the existing bindings for platform devices.

New options in Kconfig allow the platform binding code and/or the
of_platform code to be turned on.  The of_platform code is of course only
available on archs that have OF support.

The existing probe and remove methods are refactored to use new functions
create_gpio_led(), to create and register one led, and delete_gpio_led(),
to unregister and free one led.  The new probe and remove methods for the
of_platform driver can then share most of the common probe and remove code
with the platform driver.

The suspend and resume methods aren't shared, but they are very short.  The
actual led driving code is the same for LEDs created by either binding.

The OF bindings are based on patch by Anton Vorontsov
<avorontsov@ru.mvista.com>.  They have been extended to allow multiple LEDs
per device.
Signed-off-by: NTrent Piepho <tpiepho@freescale.com>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NSean MacLennan <smaclennan@pikatech.com>
Signed-off-by: NRichard Purdie <rpurdie@linux.intel.com>

This patch adds few bindings for the new drivers to be submitted through
the appropriate maintainers.
Signed-off-by: NAnton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>