The gpiolib supports parsing DT properties of the form <name>-gpio but it
was only added for compatibility with older DT bindings that got it wrong
and should not be used in newer bindings.

The commit that added support for this was:

dd34c37a ("gpio: of: Allow -gpio suffix for property names")

but didn't update the documentation to explain this so it's been a source
of confusion. So let's make this clear in the GPIO DT binding doc.
Signed-off-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NRob Herring <robh@kernel.org>

Add GPIO hogging documentation to gpio.txt
Signed-off-by: NBenoit Parrot <bparrot@ti.com>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Now that ACPI supports named GPIO properties, either through ACPI 5.1 or
the per-driver ACPI GPIO mappings, we can be more narrow about the way
GPIOs should be specified in Device Tree bindings.

This patch updates the GPIO DT bindings documentation to highlight the
following rules for new GPIO bindings:

- All new bindings must have a meaningful name (e.g. the "gpios"
  property must not be used)
- The only suffix allowed is "-gpios", no matter the number of
  descriptors in the property
- GPIOs can only be grouped under the same property when they serve the
  same purpose, a case that should remain exceptional (e.g. bit-banged
  data lines).
Signed-off-by: NAlexandre Courbot <acourbot@nvidia.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Document what we (Laurent and I, following a mailing list dicussion)
believe are best practices for the polarity flag in a GPIO specifier.

While touching the doc, I made a few minor editing changes to other
areas.
Suggested-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This patch adds the infrastructure required to register non-linear gpio
ranges through gpiolib and the standard GPIO device tree bindings.
Signed-off-by: NChristian Ruppert <christian.ruppert@abilis.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This change makes documentation of the the gpio-ranges property shorter
and more succinct, more consistent with the style of the rest of the
document, and not mention Linux-specifics such as the API
pinctrl_request_gpio(); DT binding documents should be OS independant
where at all possible. As part of this, the gpio-ranges property's format
is described in BNF form, in order to match the rest of the document.

This change also deprecates the #gpio-range-cells property. Such
properties are useful when one node references a second node, and that
second node dictates the format of the reference. However, that is not
the case here; the definition of gpio-ranges itself always dictates its
format entirely, and hence the value #gpio-range-cells must always be 3,
and hence there is no point requiring any referenced node to include
this property. The only remaining need for this property is to ensure
compatibility of DTs with older SW that was written to support the
previous version of the binding.

v4:
* Mention #gpio-range-cells as being deprecated, rather than removing all
  documentation of that property. This allows DTs to be written in a
  backwards-compatible way if desired, and also allows older DTs to be
  interpreted fully using the latest documentation.
v3:
* Mention BNF in commit description.
* Fixed typo.
* Dropped patch that removed the deprecated property from *.dts, since
  it's required to boot older kernels.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add gpio offset into "gpio-range-cells" property. It's used to support
sparse pinctrl range in gpio chip.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@linaro.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

pinctrl subsystem needs gpio chip base to prepare set of gpio
pin ranges, which a given pinctrl driver can handle. This is
important to handle pinctrl gpio request calls in order to
program a given pin properly for gpio operation.

As gpio base is allocated dynamically during gpiochip
registration, presently there exists no clean way to pass this
information to the pinctrl subsystem.

After few discussions from [1], it was concluded that may be
gpio controller reporting the pin range it supports, is a
better way than pinctrl subsystem directly registering it.

[1] http://comments.gmane.org/gmane.linux.ports.arm.kernel/184816

Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NShiraz Hashim <shiraz.hashim@st.com>
[Edited documentation a bit]
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Allow for multiple named gpio properties
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

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>

Split device tree binding out of booting-without-of.txt and put them
into their own files per binding.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>