Multiple mapping table entries could reference the same pin, and hence
"own" it. This would be unusual now that pinctrl_get() represents a single
state for a client device, but in the future when it represents all known
states for a device, this is quite likely. Implement reference counting
for pin ownership to handle this.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Dong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This change separates two aspects of struct pinctrl:
a) The data representation of the parsed mapping table, into:
1) The top-level struct pinctrl object, a single entity returned
by pinctrl_get().
2) The parsed version of each mapping table entry, struct
pinctrl_setting, of which there is one per mapping table entry.
b) The code that handles this; the code for (1) above is in core.c, and
the code to parse/execute each entry in (2) above is in pinmux.c, while
the iteration over multiple settings is lifted to core.c.
This will allow the following future changes:
1) pinctrl_get() API rework, so that struct pinctrl represents all states
for the device, and the device can select between them without calling
put()/get() again.
2) To support that, a struct pinctrl_state object will be inserted into
the data model between the struct pinctrl and struct pinctrl_setting.
3) The mapping table will be extended to allow specification of pin config
settings too. To support this, struct pinctrl_setting will be enhanced
to store either mux settings or config settings, and functions will be
added to pinconf.c to parse/execute pin configuration settings.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Dong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
There are many problems with the current pinctrl locking:
struct pinctrl_dev's gpio_ranges_lock isn't effective;
pinctrl_match_gpio_range() only holds this lock while searching for a gpio
range, but the found range is return and manipulated after releading the
lock. This could allow pinctrl_remove_gpio_range() for that range while it
is in use, and the caller may very well delete the range after removing it,
causing pinctrl code to touch the now-free range object.
Solving this requires the introduction of a higher-level lock, at least
a lock per pin controller, which both gpio range registration and
pinctrl_get()/put() will acquire.
There is missing locking on HW programming; pin controllers may pack the
configuration for different pins/groups/config options/... into one
register, and hence have to read-modify-write the register. This needs to
be protected, but currently isn't. Related, a future change will add a
"complete" op to the pin controller drivers, the idea being that each
state's programming will be programmed into the pinctrl driver followed
by the "complete" call, which may e.g. flush a register cache to HW. For
this to work, it must not be possible to interleave the pinctrl driver
calls for different devices.
As above, solving this requires the introduction of a higher-level lock,
at least a lock per pin controller, which will be held for the duration
of any pinctrl_enable()/disable() call.
However, each pinctrl mapping table entry may affect a different pin
controller if necessary. Hence, with a per-pin-controller lock, almost
any pinctrl API may need to acquire multiple locks, one per controller.
To avoid deadlock, these would need to be acquired in the same order in
all cases. This is extremely difficult to implement in the case of
pinctrl_get(), which doesn't know which pin controllers to lock until it
has parsed the entire mapping table, since it contains somewhat arbitrary
data.
The simplest solution here is to introduce a single lock that covers all
pin controllers at once. This will be acquired by all pinctrl APIs.
This then makes struct pinctrl's mutex irrelevant, since that single lock
will always be held whenever this mutex is currently held.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The introduction of the owner field on the pin descriptor was not
properly documented so fix this up.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This provides a single centralized name for the default state.
Update PIN_MAP_* macros to use this state name, instead of requiring the
user to pass a state name in.
With this change, hog entries in the mapping table are defined as those
with state name PINCTRL_STATE_DEFAULT, i.e. all entries have the same
name. This interacts badly with the nested iteration over mapping table
entries in pinctrl_hog_maps() and pinctrl_hog_map() which would now
attempt to claim each hog mapping table entry multiple times. Replacing
the custom hog code with a simple pinctrl_get()/pinctrl_enable().
Update documentation and mapping tables to use this.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Dong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
At present, pinctrl_get() assumes that all matching mapping table entries
have the same "function" value, albeit potentially applied to different
pins/groups.
This change removes this restriction; pinctrl_get() can now handle a set
of mapping tables where different functions are applied to the various
pins/groups.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
struct pinctrl_dev's pin_desc_tree_lock and pinctrl_hogs_lock aren't
useful; the data they protect is read-only except when registering or
unregistering a pinctrl_dev, and at those times, it doesn't make sense to
protect one part of the structure independently from the rest.
Move pinctrl_init_device_debugfs() to the end of pinctrl_register() so
that debugfs can't access the struct pinctrl_dev until it's fully
initialized, i.e. after the hogs are set up.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
When pins are requested/acquired/got, some device becomes the owner of
their mux setting. At this point, it isn't certain which mux function
will be selected for the pin, since this may vary between each of the
device's states in the pinctrl mapping table. As such, we should record
the owning device, not what we think the initial mux setting will be,
when requesting pins.
This doesn't make a lot of difference right now since pinctrl_get gets
only one single device/state combination, but this will make a difference
when pinctrl_get gets all states, and pinctrl_select_state can switch
between states.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* Make all functions internal to core.c static. Remove any of these from
core.h.
* Add any missing EXPORT_SYMBOL_GPL().
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This moves the per-devices struct pinctrl handles and device map
over from the pinmux part of the subsystem to the core pinctrl part.
This makes the device handles core infrastructure with the goal of
using these handles also for pin configuration, so that device
drivers (or boards etc) will need one and only one handle to the
pin control core.
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Since we want to use the former pinmux handles and mapping tables for
generic control involving both muxing and configuration we begin
refactoring by renaming them from pinmux_* to pinctrl_*.
ChangeLog v1->v2:
- Also rename the PINMUX_* macros in machine.h to PIN_ as indicated
in the documentation so as to reflect the generic nature of these
mapping entries from now on.
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
After discussion with Mark Brown in an unrelated thread about
ADC lookups, it came to my knowledge that the ability to pass
a struct device * in the regulator consumers is just a
historical artifact, and not really recommended. Since there
are no in-kernel users of these pointers, we just kill them
right now, before someone starts to use them.
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
We were not cleaning up properly after unloading a pinmux
driver compiled as module.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus 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: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus 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: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus 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: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
We want singned pins to mean "invalid" only on the outside
of the subsystem.
Signed-off-by: Marek Belisko <marek.belisko@open-nandra.com>
Signed-off-by: Linus 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: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus 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: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus 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: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus 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: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Barry Song <21cnbao@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
