Commit Graph

8 Commits

Author SHA1 Message Date
Stephen Warren 1e2082b520 pinctrl: enhance mapping table to support pin config operations
The pinctrl mapping table can now contain entries to:
* Set the mux function of a pin group
* Apply a set of pin config options to a pin or a group

This allows pinctrl_select_state() to apply pin configs settings as well
as mux settings.

v3: Fix find_pinctrl() to iterate over the correct list.
   s/_MUX_CONFIGS_/_CONFIGS_/ in mapping table macros.
   Fix documentation to use correct mapping table macro.
v2: Added numerous extra PIN_MAP_*() special-case macros.
   Fixed kerneldoc typo. Delete pinctrl_get_pin_id() and
   replace it with pin_get_from_name(). Various minor fixes.
   Updates due to rebase.

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>
2012-03-05 11:25:11 +01:00
Stephen Warren 7ecdb16fe6 pinctrl: refactor struct pinctrl handling in core.c vs pinmux.c
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>
2012-03-05 11:20:50 +01:00
Stephen Warren d4e3198736 pinctrl: enhance pinctrl_get() to handle multiple functions
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>
2012-03-02 16:12:03 +01:00
Stephen Warren 03665e0f24 pinctrl: Re-order pinmux.[ch] to match each-other
Modify the two files so that the order of function prototypes in the
header matches the order of implementations in the .c file.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2012-02-22 17:59:32 +01:00
Linus Walleij befe5bdfbb pinctrl: factor pin control handles over to the core
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>
2012-02-10 21:33:06 +01:00
Linus Walleij e93bcee00c pinctrl: move generic functions to the pinctrl_ namespace
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>
2012-02-10 21:33:02 +01:00
Tony Lindgren b9130b776e pinctrl: add checks for empty function names
This is needed as otherwise we can get the following when
dealing with buggy data in a pinmux driver for
pinmux_search_function:

Unable to handle kernel NULL pointer dereference at virtual
address 00000000
...
PC is at strcmp+0xc/0x34
LR is at pinmux_get+0x350/0x8f4
...

As we need pctldev initialized to call ops->list_functions,
let's initialize it before check_ops calls and pass the
pctldev to the check_ops functions. Do this for both pinmux
and pinconf check_ops functions.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2012-01-26 14:13:11 +01:00
Linus Walleij 2744e8afb3 drivers: create a pin control subsystem
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>
2011-10-13 12:49:17 +02:00