Commit Graph

20 Commits

Author SHA1 Message Date
Dmitry Torokhov 22c403676d gpio: return NULL from gpiod_get_optional when GPIOLIB is disabled
Given the intent behind gpiod_get_optional() and friends it does not make
sense to return -ENOSYS when GPIOLIB is disabled: the driver is expected to
work just fine without gpio so let's behave as if gpio was not found.
Otherwise we have to special-case -ENOSYS in drivers.

Note that there was objection that someone might forget to enable GPIOLIB
when dealing with a platform that has device that actually specifies
optional gpio and we'll break it. I find this unconvincing as that would
have to be the *only GPIO* in the system, which is extremely unlikely.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-03-15 11:16:30 +01:00
Masanari Iida 547d4c1078 Doc: gpio: Fix typos in Documentation/gpio
This patch fix some spelling typos found in Documentation/gpio.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-11-20 16:51:16 -07:00
Dirk Behme 87e77e46c6 Documentation: gpio: board: describe the con_id parameter
The con_id parameter has to match the GPIO description and is automatically
extended by the GPIO suffix if not NULL. I had to look into the code to
understand this and properly find the GPIO I've been looking for, so document
this.

Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-09-14 09:12:03 +02:00
Dirk Behme ac49fbd1f9 Documentation: gpio: consumer: describe active low property
I've been searching for any documentation of 'the active-low property of a GPIO'
already mentioned in this documenation. But couldn't find any. Add it.

Sigend-off-by: Dirk Behme <dirk.behme@gmail.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
[Spelling, grammar fixes]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-08-17 10:38:52 +02:00
Linus Torvalds 1e467e68e5 Documentation updates for 4.2
The main thing here is Ingo's big subdirectory documenting feature support
 for each architecture.  Beyond that, it's the usual pile of fixes, tweaks,
 and small additions.
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Merge tag 'docs-for-linus' of git://git.lwn.net/linux-2.6

Pull documentation updates from Jonathan Corbet:
 "The main thing here is Ingo's big subdirectory documenting feature
  support for each architecture.  Beyond that, it's the usual pile of
  fixes, tweaks, and small additions"

* tag 'docs-for-linus' of git://git.lwn.net/linux-2.6: (79 commits)
  doc:md: fix typo in md.txt.
  Documentation/mic/mpssd: don't build x86 userspace when cross compiling
  Documentation/prctl: don't build tsc tests when cross compiling
  Documentation/vDSO: don't build tests when cross compiling
  Doc:ABI/testing: Fix typo in sysfs-bus-fcoe
  Doc: Docbook: Change wikipedia's URL from http to https in scsi.tmpl
  Doc: Change wikipedia's URL from http to https
  Documentation/kernel-parameters: add missing pciserial to the earlyprintk
  Doc:pps: Fix typo in pps.txt
  kbuild : Fix documentation of INSTALL_HDR_PATH
  Documentation: filesystems: updated struct file_operations documentation in vfs.txt
  kbuild: edit explanation of clean-files variable
  Doc: ja_JP: Fix typo in HOWTO
  Move freefall program from Documentation/ to tools/
  Documentation: ARM: EXYNOS: Describe boot loaders interface
  Doc:nfc: Fix typo in nfc-hci.txt
  vfs: Minor documentation fix
  Doc: networking: txtimestamp: fix printf format warning
  Documentation, intel_pstate: Improve legacy mode internal governors description
  Documentation: extend use case for EXPORT_SYMBOL_GPL()
  ...
2015-06-24 20:01:36 -07:00
Rojhalat Ibrahim e2bfba4185 fix documentation after renaming gpiod_set_array to gpiod_set_array_value
Patch "gpiolib: rename gpiod_set_array to gpiod_set_array_value" omitted
to also change the function names in the documentation. Let's fix that.

Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-06-04 10:46:43 +02:00
Geert Uytterhoeven cbfa2c5281 gpiolib: Grammar s/an negative/a negative/
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-05-22 09:31:15 -06:00
Rojhalat Ibrahim de3b696542 extend documentation for gpiod_set_array() functions
Extend the documentation for the gpiod_set_array() functions and elaborate
a bit on possible use cases.

Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-03-09 17:38:49 +01:00
Rojhalat Ibrahim 331758eef8 gpiolib: add devm_gpiod_get_array and devm_gpiod_put_array functions
Add device managed variants of gpiod_get_array() / gpiod_put_array()
functions for conveniently obtaining and disposing of an entire array
of GPIOs with one function call.

Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-03-05 09:55:42 +01:00
Rojhalat Ibrahim 6685852732 gpiolib: add gpiod_get_array and gpiod_put_array functions
Introduce new functions for conveniently obtaining and disposing of
an entire array of GPIOs with one function call.

ACPI parts tested by Mika Westerberg, DT parts tested by Rojhalat
Ibrahim.

Change log:
v5: move the ACPI functions to gpiolib-acpi.c
v4: - use shorter names for members of struct gpio_descs
    - rename lut_gpio_count to platform_gpio_count for clarity
    - add check for successful memory allocation
    - use ERR_CAST()
v3: - rebase on current linux-gpio devel branch
    - fix ACPI GPIO counting
    - allow for zero-sized arrays
    - make the flags argument mandatory for the new functions
    - clarify documentation
v2: change interface

Suggested-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Rojhalat Ibrahim <imr@rtschenk.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-03-05 09:52:28 +01:00
Linus Torvalds 980f3c344f This is the bulk of GPIO changes for the v3.19 series:
- A new API that allows setting more than one GPIO at the
   time. This is implemented for the new descriptor-based
   API only and makes it possible to e.g. toggle a clock and
   data line at the same time, if the hardware can do this
   with a single register write. Both consumers and drivers
   need new calls, and the core will fall back to driving
   individual lines where needed. Implemented for the MPC8xxx
   driver initially.
 - Patched the mdio-mux-gpio and the serial mctrl driver
   that drives modems to use the new multiple-setting API
   to set several signals simultaneously.
 - Get rid of the global GPIO descriptor array, and instead
   allocate descriptors dynamically for each GPIO on a certain
   GPIO chip. This moves us closer to getting rid of the
   limitation of using the global, static GPIO numberspace.
 - New driver and device tree bindings for 74xx ICs.
 - New driver and device tree bindings for the VF610 Vybrid.
 - Support the RCAR r8a7793 and r8a7794.
 - Guidelines for GPIO device tree bindings trying to get
   things a bit more strict with the advent of combined
   device properties.
 - Suspend/resume support for the MVEBU driver.
 - A slew of minor fixes and improvements.
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Merge tag 'gpio-v3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull take two of the GPIO updates:
 "Same stuff as last time, now with a fixup patch for the previous
  compile error plus I ran a few extra rounds of compile-testing.

  This is the bulk of GPIO changes for the v3.19 series:

   - A new API that allows setting more than one GPIO at the time.  This
     is implemented for the new descriptor-based API only and makes it
     possible to e.g. toggle a clock and data line at the same time, if
     the hardware can do this with a single register write.  Both
     consumers and drivers need new calls, and the core will fall back
     to driving individual lines where needed.  Implemented for the
     MPC8xxx driver initially

   - Patched the mdio-mux-gpio and the serial mctrl driver that drives
     modems to use the new multiple-setting API to set several signals
     simultaneously

   - Get rid of the global GPIO descriptor array, and instead allocate
     descriptors dynamically for each GPIO on a certain GPIO chip.  This
     moves us closer to getting rid of the limitation of using the
     global, static GPIO numberspace

   - New driver and device tree bindings for 74xx ICs

   - New driver and device tree bindings for the VF610 Vybrid

   - Support the RCAR r8a7793 and r8a7794

   - Guidelines for GPIO device tree bindings trying to get things a bit
     more strict with the advent of combined device properties

   - Suspend/resume support for the MVEBU driver

   - A slew of minor fixes and improvements"

* tag 'gpio-v3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (33 commits)
  gpio: mcp23s08: fix up compilation error
  gpio: pl061: document gpio-ranges property for bindings file
  gpio: pl061: hook request if gpio-ranges avaiable
  gpio: mcp23s08: Add option to configure IRQ output polarity as active high
  gpio: fix deferred probe detection for legacy API
  serial: mctrl_gpio: use gpiod_set_array function
  mdio-mux-gpio: Use GPIO descriptor interface and new gpiod_set_array function
  gpio: remove const modifier from gpiod_get_direction()
  gpio: remove gpio_descs global array
  gpio: mxs: implement get_direction callback
  gpio: em: Use dynamic allocation of GPIOs
  gpio: Check if base is positive before calling gpio_is_valid()
  gpio: mcp23s08: Add simple IRQ support for SPI devices
  gpio: mcp23s08: request a shared interrupt
  gpio: mcp23s08: Do not free unrequested interrupt
  gpio: rcar: Add r8a7793 and r8a7794 support
  gpio-mpc8xxx: add mpc8xxx_gpio_set_multiple function
  gpiolib: allow simultaneous setting of multiple GPIO outputs
  gpio: mvebu: add suspend/resume support
  gpio: gpio-davinci: remove duplicate check on resource
  ..
2014-12-14 14:05:05 -08:00
Rojhalat Ibrahim 5f42424354 gpiolib: allow simultaneous setting of multiple GPIO outputs
Introduce new functions gpiod_set_array & gpiod_set_raw_array to the consumer
interface which allow setting multiple outputs with just one function call.
Also add an optional set_multiple function to the driver interface. Without an
implementation of that function in the chip driver outputs are set
sequentially.

Implementing the set_multiple function in a chip driver allows for:
- Improved performance for certain use cases. The original motivation for this
  was the task of configuring an FPGA. In that specific case, where 9 GPIO
  lines have to be set many times, configuration time goes down from 48 s to
  20 s when using the new function.
- Simultaneous glitch-free setting of multiple pins on any kind of parallel
  bus attached to GPIOs provided they all reside on the same chip and bank.

Limitations:
  Performance is only improved for normal high-low outputs. Open drain and
  open source outputs are always set separately from each other. Those kinds
  of outputs could probably be accelerated in a similar way if we could
  forgo the error checking when setting GPIO directions.

Change log:
  v6: - rebase on current linux-gpio devel branch
  v5: - check can_sleep property per chip
      - remove superfluous checks
      - supplement documentation
  v4: - add gpiod_set_array function for setting logical values
      - change interface of the set_multiple driver function to use
        unsigned long as type for the bit fields
      - use generic bitops (which also use unsigned long for bit fields)
      - do not use ARCH_NR_GPIOS any more
  v3: - add documentation
      - change commit message
  v2: - use descriptor interface
      - allow arbitrary groups of GPIOs spanning multiple chips

Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-11-27 15:01:18 +01:00
Rafael J. Wysocki e36d453e98 ACPI / GPIO: Document ACPI GPIO mappings API
Document the previously introduced method that can be used by device
drivers to provide the GPIO subsystem with mappings between GPIO names
(connection IDs) and GpioIo()/GpioInt() resources in _CRS.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2014-11-04 21:58:24 +01:00
Alexandre Courbot 1b11a9b9e0 Documentation: gpio: documentation for optional getters functions
Add a mention about the _optional variants of (devm_)gpiod_get*().

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-08-29 08:53:53 +02:00
Alexandre Courbot 39b2bbe3d7 gpio: add flags argument to gpiod_get*() functions
The huge majority of GPIOs have their direction and initial value set
right after being obtained by one of the gpiod_get() functions. The
integer GPIO API had gpio_request_one() that took a convenience flags
parameter allowing to specify an direction and value applied to the
returned GPIO. This feature greatly simplifies client code and ensures
errors are always handled properly.

A similar feature has been requested for the gpiod API. Since setting
the direction of a GPIO is so often the very next action done after
obtaining its descriptor, we prefer to extend the existing functions
instead of introducing new functions that would raise the
number of gpiod getters to 16 (!).

The drawback of this approach is that all gpiod clients need to be
updated. To limit the pain, temporary macros are introduced that allow
gpiod_get*() to be called with or without the extra flags argument. They
will be removed once all consumer code has been updated.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-28 12:28:05 +02:00
Linus Torvalds 1aacb90eaa Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial into next
Pull trivial tree changes from Jiri Kosina:
 "Usual pile of patches from trivial tree that make the world go round"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (23 commits)
  staging: go7007: remove reference to CONFIG_KMOD
  aic7xxx: Remove obsolete preprocessor define
  of: dma: doc fixes
  doc: fix incorrect formula to calculate CommitLimit value
  doc: Note need of bc in the kernel build from 3.10 onwards
  mm: Fix printk typo in dmapool.c
  modpost: Fix comment typo "Modules.symvers"
  Kconfig.debug: Grammar s/addition/additional/
  wimax: Spelling s/than/that/, wording s/destinatary/recipient/
  aic7xxx: Spelling s/termnation/termination/
  arm64: mm: Remove superfluous "the" in comment
  of: Spelling s/anonymouns/anonymous/
  dma: imx-sdma: Spelling s/determnine/determine/
  ath10k: Improve grammar in comments
  ath6kl: Spelling s/determnine/determine/
  of: Improve grammar for of_alias_get_id() documentation
  drm/exynos: Spelling s/contro/control/
  radio-bcm2048.c: fix wrong overflow check
  doc: printk-formats: do not mention casts for u64/s64
  doc: spelling error changes
  ...
2014-06-04 08:50:34 -07:00
Carlos Garcia c98be0c96d doc: spelling error changes
Fixed multiple spelling errors.

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Carlos E. Garcia <carlos@cgarcia.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-05-05 15:32:05 +02:00
Philipp Zabel ef70bbe1aa gpio: make gpiod_direction_output take a logical value
The documentation was not clear about whether
gpio_direction_output should take a logical value or the physical
level on the output line, i.e. whether the ACTIVE_LOW status
would be taken into account.

This converts gpiod_direction_output to use the logical level
and adds a new gpiod_direction_output_raw for the raw value.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-02-07 09:47:02 +01:00
Alexandre Courbot 2a3cf6a359 gpiolib: return -ENOENT if no GPIO mapping exists
Some devices drivers make use of optional GPIO parameters. For such
drivers, it is important to discriminate between the case where no
GPIO mapping has been defined for the function they are requesting, and
the case where a mapping exists but an error occured while resolving it
or when acquiring the GPIO.

This patch changes the family of gpiod_get() functions such that they
will return -ENOENT if and only if no GPIO mapping is defined for the
requested function. Other error codes are used when an actual error
occured during the GPIO resolution.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-12-12 19:33:59 +01:00
Alexandre Courbot fd8e198cfc Documentation: gpiolib: document new interface
gpiolib now exports a new descriptor-based interface which deprecates
the older integer-based one. This patch documents this new interface and
also takes the opportunity to brush-up the GPIO documentation a little
bit.

The new descriptor-based interface follows the same consumer/driver
model as many other kernel subsystems (e.g. clock, regulator), so its
documentation has similarly been splitted into different files.

The content of the former documentation has been reused whenever it
made sense; however, some of its content did not apply to the new
interface anymore and have this been removed. Likewise, new sections
like the mapping of GPIOs to devices have been written from scratch.

The deprecated legacy-based documentation is still available, untouched,
under Documentation/gpio/gpio-legacy.txt.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-11-25 09:02:30 +01:00