Fix some pinmux typos so implementing pinmux drivers
is a bit easier.
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

We were not cleaning up properly after unloading a pinmux
driver compiled as module.
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

It's better to not line break error messages to allow easier grepping
for them even when the line gets >80 chars. Additionally some minor
reformating is done.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Commit 706e8520 "pinctrl: correct a offset while enumerating pins"
modified the variable used by pinconf_pin_show()'s for loop, but didn't
update the for loop test expression.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This patch removes maxpin member in the pin control descriptor
because we don't need this value as we enumerate a pin space
using offset.
Signed-off-by: NChanho Park <chanho61.park@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This patch modifies a offset while enumerating pins to support a
partial pin space. If we use a pin number for enumerating pins,
the pin space always starts with zero base. Indeed, we always check
the pin is in the pin space. An extreme example, there is only two pins.
One is 0. Another is 1000. We always enumerate whole offsets until 1000.
For solving this problem, we use the offset of the pin array instead
of the zero-based pin number.
Signed-off-by: NChanho Park <chanho61.park@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
[Restored sparse pin space comment]
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Minor copyedits.
Signed-off-by: NDong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

For stringent order, rename the pinmux-* pin controllers to
pinctrl-* and also rename the Kconfig symbols and in-kernel
users.

Cc: Rongjun Ying <Rongjun.Ying@csr.com>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Obtaining a "struct pinctrl_dev *" is difficult for code not directly
related to the pinctrl subsystem. However, the device name of the pinctrl
device is fairly well known. So, modify pin_config_*() to take the device
name instead of the "struct pinctrl_dev *".
Signed-off-by: NStephen Warren <swarren@nvidia.com>
[rebased on top of refactoring code]
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

If pins with blank names are registered, we assign them names on-the-fly
on the form "PINn" where n is the pin number for that pin on the specific
controller.
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Pin controllers should already be instantiated as a device, so there's
no need for the pinctrl core to create a new struct device for each
controller.

This allows the controller's real name to be used in the mux mapping
table, rather than e.g. "pinctrl.0", "pinctrl.1", etc.

This necessitates removal of the PINMUX_MAP_PRIMARY*() macros, since
their sole purpose was to hard-code the .ctrl_dev_name field to be
"pinctrl.0".
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This add per-pin and per-group pin config interfaces for biasing,
driving and other such electronic properties. The details of passed
configurations are passed in an opaque unsigned long which may be
dereferences to integer types, structs or lists on either side
of the configuration interface.

ChangeLog v1->v2:
- Clear split of terminology: we now have pin controllers, and
  those may support two interfaces using vtables: pin
  multiplexing and pin configuration.
- Break out pin configuration to its own C file, controllers may
  implement only config without mux, and vice versa, so keep each
  sub-functionality of pin controllers separate. Introduce
  CONFIG_PINCONF in Kconfig.
- Implement some core logic around pin configuration in the
  pinconf.c file.
- Remove UNKNOWN config states, these were just surplus baggage.
- Remove FLOAT config state - HIGH_IMPEDANCE should be enough for
  everyone.
- PIN_CONFIG_POWER_SOURCE added to handle switching the power
  supply for the pin logic between different sources
- Explicit DISABLE config enums to turn schmitt-trigger,
  wakeup etc OFF.
- Update documentation to reflect all the recent reasoning.
ChangeLog v2->v3:
- Twist API around to pass around arrays of config tuples instead
  of (param, value) pairs everywhere.
- Explicit drive strength semantics for push/pull and similar
  drive modes, this shall be the number of drive stages vs
  nominal load impedance, which should match the actual
  electronics used in push/pull CMOS or TTY totempoles.
- Drop load capacitance configuration - I probably don't know
  what I'm doing here so leave it out.
- Drop PIN_CONFIG_INPUT_SCHMITT_OFF, instead the argument zero to
  PIN_CONFIG_INPUT_SCHMITT turns schmitt trigger off.
- Drop PIN_CONFIG_NORMAL_POWER_MODE and have a well defined
  argument to PIN_CONFIG_LOW_POWER_MODE to get out of it instead.
- Drop PIN_CONFIG_WAKEUP_ENABLE/DISABLE and just use
  PIN_CONFIG_WAKEUP with defined value zero to turn wakeup off.
- Add PIN_CONFIG_INPUT_DEBOUNCE for configuring debounce time
  on input lines.
- Fix a bug when we tried to configure pins for pin controllers
  without pinconf support.
- Initialized debugfs properly so it works.
- Initialize the mutex properly and lock around config tampering
  sections.
- Check the return value from get_initial_config() properly.
ChangeLog v3->v4:
- Export the pin_config_get(), pin_config_set() and
  pin_config_group() functions.
- Drop the entire concept of just getting initial config and
  keeping track of pin states internally, instead ask the pins
  what state they are in. Previous idea was plain wrong, if the
  device cannot keep track of its state, the driver should do
  it.
- Drop the generic configuration layout, it seems this impose
  too much restriction on some pin controllers, so let them do
  things the way they want and split off support for generic
  config as an optional add-on.
ChangeLog v4->v5:
- Introduce two symmetric driver calls for group configuration,
  .pin_config_group_[get|set] and corresponding external calls.
- Remove generic semantic meanings of return values from config
  calls, these belong in the generic config patch. Just pass the
  return value through instead.
- Add a debugfs entry "pinconf-groups" to read status from group
  configuration only, also slam in a per-group debug callback in
  the pinconf_ops so custom drivers can display something
  meaningful for their pins.
- Fix some dangling newline.
- Drop dangling #else clause.
- Update documentation to match the above.
ChangeLog v5->v6:
- Change to using a pin name as parameter for the
  [get|set]_config() functions, as suggested by Stephen Warren.
  This is more natural as names will be what a developer has
  access to in written documentation etc.
ChangeLog v6->v7:
- Refactor out by-pin and by-name get/set functions, only expose
  the by-name functions externally, expose the by-pin functions
  internally.
- Show supported pin control functionality in the debugfs
  pinctrl-devices file.
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This makes the COH 901 driver request muxing of its GPIO pins
from the pinmux-u300 driver using the standard API calls.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This register the actual GPIO ranges used by the COH901XXX GPIO
driver.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This driver will be converted to a dual GPIO + pinctrl driver
since it supports biasing and driving control options. Hopefully
it can serve as an example.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Since we now anyway make a copy of the platform-supplied pinmux
map, we can just as well make it possible to call the function
adding maps several times, so as to simplify cases (as PXA) where
several sets of disparate mappings need to be added depending on
target platform.
Acked-by: NHaojian Zhuang <haojian.zhuang@gmail.com>
Acked-by: NArnd Bergmann <arnd@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This makes a deep copy of the pinmux function map instead of
keeping the copy supplied from the platform around. This makes
it possible to tag the platforms map with __initdata as is also
done as part of this patch.

Rationale: a certain target platform (PXA) has numerous
pinmux maps, many of which will be lying around unused after
boot in a multi-platform binary. Instead, deep-copy the one
we're going to use and tag them all __initdata so they go away
after boot.

ChangeLog v1->v2:
- Fixup the deep copy, missed a few items on the struct,
  plus mark bool member non-const since we're making runtime
  copies if this stuff now.
ChangeLog v2->v3:
- Make a shallow copy (just copy the array of map structs)
  as Arnd noticed, string constants never get discarded by the
  kernel anyway, so these pointers may be safely copied over.
Reviewed-by: NArnd Bergmann <arnd.bergmann@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

When requesting a single GPIO pin to be muxed in, some controllers
will need to poke a different value into the control register
depending on whether the pin will be used for GPIO output or GPIO
input. So create pinmux counterparts to gpio_direction_[input|output]
in the pinctrl framework.

ChangeLog v1->v2:
- This also amends the documentation to make it clear the this
  function and associated machinery is *ONLY* intended as a backend
  to gpiolib machinery, not for everyone and his dog to start playing
  around with pins.
ChangeLog v2->v3:
- Don't pass an argument to the common request function, instead
  provide pinmux_* counterparts to the gpio_direction_[input|output]
  calls, simpler and anyone can understand it.
ChangeLog v3->v4:
- Fix numerous spelling mistakes and dangling text in documentation.
  Add Ack and Rewewed-by.

Cc: Igor Grinberg <grinberg@compulab.co.il>
Acked-by: NStephen Warren <swarren@nvidia.com>
Reviewed-by: NThomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Show the mapped pin range corresponding to the GPIO range in
debugfs for pin controllers.
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This patch enables mapping a base offset of gpio ranges with
a pin offset even if does'nt matched. A base of pinctrl_gpio_range
means a base offset of gpio. However, we cannot convert gpio to pin
number for sparse gpio ranges just only using a gpio base offset.
We can convert a gpio to real pin number(even if not matched) using
a new pin_base which means a base pin offset of requested gpio range.
Now, the pin control subsystem passes the pin base offset to the
pinmux driver.

For example, let's assume below two gpio ranges in the system.

static struct pinctrl_gpio_range gpio_range_a = {
    .name = "chip a",
    .id = 0,
    .base = 32,
    .pin_base = 32,
    .npins = 16,
    .gc = &chip_a;
};

static struct pinctrl_gpio_range gpio_range_b = {
    .name = "chip b",
    .id = 0,
    .base = 48,
    .pin_base = 64,
    .npins = 8,
    .gc = &chip_b;
};

We can calucalate a exact pin ranges even if doesn't matched with gpio ranges.

chip a:
    gpio-range : [32 .. 47]
    pin-range  : [32 .. 47]
chip b:
    gpio-range : [48 .. 55]
    pin-range  : [64 .. 71]
Signed-off-by: NChanho Park <chanho61.park@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

We want singned pins to mean "invalid" only on the outside
of the subsystem.
Signed-off-by: NMarek Belisko <marek.belisko@open-nandra.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Update the docs removing an obsolete __refdata tag and document
the mysterious return value of pin_free(). And fixes up some various
confusions in the pinctrl documentation.
Reported-by: NRajendra Nayak <rnayak@ti.com>
Reported-by: NRandy Dunlap <rdunlap@xenotime.net>
Reported-by: NThomas Abraham <thomas.abraham@linaro.org>
Reported-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Some pinctrl drivers (Tegra at least) program a pin to be a GPIO in a
completely different manner than they select which function to mux out of
that pin. In order to support a single "free" pinmux_op, the driver would
need to maintain a per-pin state of requested-for-gpio vs. requested-for-
function. However, that's a lot of work when the core already has explicit
separate paths for gpio request/free and function request/free.

So, add a gpio_disable_free op to struct pinmux_ops, and make pin_free()
call it when appropriate.

When doing this, I noticed that when calling pin_request():

    !!gpio == (gpio_range != NULL)

... and so I collapsed those two parameters in both pin_request(), and
when adding writing the new code in pin_free().

Also, for pin_free():

    !!free_func == (gpio_range != NULL)

However, I didn't want pin_free() to know about the GPIO function naming
special case, so instead, I reworked pin_free() to always return the pin's
previously requested function, and now pinmux_free_gpio() calls
kfree(function). This is much more balanced with the allocation having
been performed in pinmux_request_gpio().
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Function pin_is_valid just call pin_desc_get which is in pin_request
call some line below. Remove pin_is_valid() check.
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NMarek Belisko <marek.belisko@open-nandra.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Now also the core needs to look up pin groups so move the lookup
function there and expose it in the internal header.
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Fix u300_pmx_endisable() to iterate over the list of 'bits' and
'mask' populated as part of u300_pmx_functions.mask[]
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

DEBUG_PINCTRL wasn't used at all and DEBUG_PINMUX doesn't exist.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Machines that have embedded pin controllers need to select them
explicitly, so why broadcast their config options to menuconfig.
We provide a helpful submenu for those machines that do select
it, making it possible to enable debugging for example.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

fix sirfsoc_get_group_pins prototype introduced in 7e570f97, we
missed to de-constify a pointer.
Signed-off-by: NJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Instead, store a pointer to the currently assigned function.

This allows us to delete the mux_requested variable from pin_desc; a pin
is requested if its currently assigned function is non-NULL.

When a pin is requested as a GPIO rather than a regular function, the
assigned function name is dynamically constructed. In this case, we have
to kstrdup() the dynamically constructed name, so that mux_function doesn't
pointed at stack data. This requires pin_free to be told whether to free
the mux_function pointer or not.

This removes the hard-coded maximum function name length.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

A pin controller's names array is no longer marked __refdata. Hence, we
can avoid copying a pin's name into the descriptor when registering it.
Instead, just point at the string supplied in the pin array.

This both simplifies and speeds up pin controller initialization, but
also removes the hard-coded maximum pin name length.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

A pin controller's pin definitions are used both during pinctrl_register()
and pinctrl_unregister(). The latter happens outside of __init/__devinit
time, and hence it is unsafe to mark the pin array as __refdata.
Acked-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

get_group_pins() "returns" a pointer to an array of const objects, through
a pointer parameter. Fix the prototype so what's pointed at by the returned
pointer is const, rather than the function parameter being const.

This also allows the removal of a cast in each of the two current pinmux
drivers.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This creates a pin controller driver for the SiRFprinaII
pin mux portions.
Signed-off-by: NRongjun Ying <Rongjun.Ying@csr.com>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
[Fixup for changed function names and semantics in the v10 patch]
Signed-off-by: NLinus Walleij <linus.walleij@stericsson.com>

This adds a driver for the U300 pinmux portions of the system
controller "SYSCON". It also serves as an example of how to use
the pinmux subsystem. This driver also houses the platform data
for the only supported platform.

This deletes the old U300 driver in arch/arm/mach-u300 and
replace it with a driver using the new subsystem.

The new driver is considerably fatter than the old one, but it
also registers all 467 pins of the system and adds the power
and EMIF pin groups and corresponding functions. The idea
is to use this driver as a a reference for other
implementation so it needs to be as complete and verbose
as possible.
Reviewed-by: NBarry Song <21cnbao@gmail.com>
[Fixup for changed function names and semantics in the v10 patch]
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This creates a subsystem for handling of pin control devices.
These are devices that control different aspects of package
pins.

Currently it handles pinmuxing, i.e. assigning electronic
functions to groups of pins on primarily PGA and BGA type of
chip packages which are common in embedded systems.

The plan is to also handle other I/O pin control aspects
such as biasing, driving, input properties such as
schmitt-triggering, load capacitance etc within this
subsystem, to remove a lot of ARM arch code as well as
feature-creepy GPIO drivers which are implementing the same
thing over and over again.

This is being done to depopulate the arch/arm/* directory
of such custom drivers and try to abstract the infrastructure
they all need. See the Documentation/pinctrl.txt file that is
part of this patch for more details.

ChangeLog v1->v2:

- Various minor fixes from Joe's and Stephens review comments
- Added a pinmux_config() that can invoke custom configuration
  with arbitrary data passed in or out to/from the pinmux driver

ChangeLog v2->v3:

- Renamed subsystem folder to "pinctrl" since we will likely
  want to keep other pin control such as biasing in this
  subsystem too, so let us keep to something generic even though
  we're mainly doing pinmux now.
- As a consequence, register pins as an abstract entity separate
  from the pinmux. The muxing functions will claim pins out of the
  pin pool and make sure they do not collide. Pins can now be
  named by the pinctrl core.
- Converted the pin lookup from a static array into a radix tree,
  I agreed with Grant Likely to try to avoid any static allocation
  (which is crap for device tree stuff) so I just rewrote this
  to be dynamic, just like irq number descriptors. The
  platform-wide definition of number of pins goes away - this is
  now just the sum total of the pins registered to the subsystem.
- Make sure mappings with only a function name and no device
  works properly.

ChangeLog v3->v4:

- Define a number space per controller instead of globally,
  Stephen and Grant requested the same thing so now maps need to
  define target controller, and the radix tree of pin descriptors
  is a property on each pin controller device.
- Add a compulsory pinctrl device entry to the pinctrl mapping
  table. This must match the pinctrl device, like "pinctrl.0"
- Split the file core.c in two: core.c and pinmux.c where the
  latter carry all pinmux stuff, the core is for generic pin
  control, and use local headers to access functionality between
  files. It is now possible to implement a "blank" pin controller
  without pinmux capabilities. This split will make new additions
  like pindrive.c, pinbias.c etc possible for combined drivers
  and chunks of functionality which is a GoodThing(TM).
- Rewrite the interaction with the GPIO subsystem - the pin
  controller descriptor now handles this by defining an offset
  into the GPIO numberspace for its handled pin range. This is
  used to look up the apropriate pin controller for a GPIO pin.
  Then that specific GPIO range is matched 1-1 for the target
  controller instance.
- Fixed a number of review comments from Joe Perches.
- Broke out a header file pinctrl.h for the core pin handling
  stuff that will be reused by other stuff than pinmux.
- Fixed some erroneous EXPORT() stuff.
- Remove mispatched U300 Kconfig and Makefile entries
- Fixed a number of review comments from Stephen Warren, not all
  of them - still WIP. But I think the new mapping that will
  specify which function goes to which pin mux controller address
  50% of your concerns (else beat me up).

ChangeLog v4->v5:

- Defined a "position" for each function, so the pin controller now
  tracks a function in a certain position, and the pinmux maps define
  what position you want the function in. (Feedback from Stephen
  Warren and Sascha Hauer).
- Since we now need to request a combined function+position from
  the machine mapping table that connect mux settings to drivers,
  it was extended with a position field and a name field. The
  name field is now used if you e.g. need to switch between two
  mux map settings at runtime.
- Switched from a class device to using struct bus_type for this
  subsystem. Verified sysfs functionality: seems to work fine.
  (Feedback from Arnd Bergmann and Greg Kroah-Hartman)
- Define a per pincontroller list of GPIO ranges from the GPIO
  pin space that can be handled by the pin controller. These can
  be added one by one at runtime. (Feedback from Barry Song)
- Expanded documentation of regulator_[get|enable|disable|put]
  semantics.
- Fixed a number of review comments from Barry Song. (Thanks!)

ChangeLog v5->v6:

- Create an abstract pin group concept that can sort pins into
  named and enumerated groups no matter what the use of these
  groups may be, one possible usecase is a group of pins being
  muxed in or so. The intention is however to also use these
  groups for other pin control activities.
- Make it compulsory for pinmux functions to associate with
  at least one group, so the abstract pin group concept is used
  to define the groups of pins affected by a pinmux function.
  The pinmux driver interface has been altered so as to enforce
  a function to list applicable groups per function.
- Provide an optional .group entry in the pinmux machine map
  so the map can select beteween different available groups
  to be used with a certain function.
- Consequent changes all over the place so that e.g. debugfs
  present reasonable information about the world.
- Drop the per-pin mux (*config) function in the pinmux_ops
  struct - I was afraid that this would start to be used for
  things totally unrelated to muxing, we can introduce that to
  the generic struct pinctrl_ops if needed. I want to keep
  muxing orthogonal to other pin control subjects and not mix
  these things up.

ChangeLog v6->v7:

- Make it possible to have several map entries matching the
  same device, pin controller and function, but using
  a different group, and alter the semantics so that
  pinmux_get() will pick all matching map entries, and
  store the associated groups in a list. The list will
  then be iterated over at pinmux_enable()/pinmux_disable()
  and corresponding driver functions called for each
  defined group. Notice that you're only allowed to map
  multiple *groups* to the same
  { device, pin controller, function } triplet, attempts
  to map the same device to multiple pin controllers will
  for example fail. This is hopefully the crucial feature
  requested by Stephen Warren.
- Add a pinmux hogging field to the pinmux mapping entries,
  and enable the pinmux core to hog pinmux map entries.
  This currently only works for pinmuxes without assigned
  devices as it looks now, but with device trees we can
  look up the corresponding struct device * entries when
  we register the pinmux driver, and have it hog each
  pinmux map in turn, for a simple approach to
  non-dynamic pin muxing. This addresses an issue from
  Grant Likely that the machine should take care of as
  much of the pinmux setup as possible, not the devices.
  By supplying a list of hogs, it can now instruct the
  core to take care of any static mappings.
- Switch pinmux group retrieveal function to grab an
  array of strings representing the groups rather than an
  array of unsigned and rewrite accordingly.
- Alter debugfs to show the grouplist handled by each
  pinmux. Also add a list of hogs.
- Dynamically allocate a struct pinmux at pinmux_get() and
  free it at pinmux_put(), then add these to the global
  list of pinmuxes active as we go along.
- Go over the list of pinmux maps at pinmux_get() time
  and repeatedly apply matches.
- Retrieve applicable groups per function from the driver
  as a string array rather than a unsigned array, then
  lookup the enumerators.
- Make the device to pinmux map a singleton - only allow the
  mapping table to be registered once and even tag the
  registration function with __init so it surely won't be
  abused.
- Create a separate debugfs file to view the pinmux map at
  runtime.
- Introduce a spin lock to the pin descriptor struct, lock it
  when modifying pin status entries. Reported by Stijn Devriendt.
- Fix up the documentation after review from Stephen Warren.
- Let the GPIO ranges give names as const char * instead of some
  fixed-length string.
- add a function to unregister GPIO ranges to mirror the
  registration function.
- Privatized the struct pinctrl_device and removed it from the
  <linux/pinctrl/pinctrl.h> API, the drivers do not need to know
  the members of this struct. It is now in the local header
  "core.h".
- Rename the concept of "anonymous" mux maps to "system" muxes
  and add convenience macros and documentation.

ChangeLog v7->v8:

- Delete the leftover pinmux_config() function from the
 <linux/pinctrl/pinmux.h> header.
- Fix a race condition found by Stijn Devriendt in pin_request()

ChangeLog v8->v9:

- Drop the bus_type and the sysfs attributes and all, we're not on
  the clear about how this should be used for e.g. userspace
  interfaces so let us save this for the future.
- Use the right name in MAINTAINERS, PIN CONTROL rather than
  PINMUX
- Don't kfree() the device state holder, let the .remove() callback
  handle this.
- Fix up numerous kerneldoc headers to have one line for the function
  description and more verbose documentation below the parameters

ChangeLog v9->v10:
- pinctrl: EXPORT_SYMBOL needs export.h, folded in a patch
  from Steven Rothwell
- fix pinctrl_register error handling, folded in a patch from
  Axel Lin
- Various fixes to documentation text so that it's consistent.
- Removed pointless comment from drivers/Kconfig
- Removed dependency on SYSFS since we removed the bus in
  v9.
- Renamed hopelessly abbreviated pctldev_* functions to the
  more verbose pinctrl_dev_*
- Drop mutex properly when looking up GPIO ranges
- Return NULL instead of ERR_PTR() errors on registration of
  pin controllers, using cast pointers is fragile. We can
  live without the detailed error codes for sure.

Cc: Stijn Devriendt <highguy@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NStephen Warren <swarren@nvidia.com>
Tested-by: NBarry Song <21cnbao@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>