Commit Graph

74 Commits

Author SHA1 Message Date
Bartosz Golaszewski
4147d76f98 gpio: sysfs: drop the mention of gpiochip_find() from sysfs code
[ Upstream commit e404b0cc9f ]

We have removed all callers of gpiochip_find() so don't mention it in
gpiolib-sysfs.c.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Stable-dep-of: 48e1b4d369 ("gpiolib: remove the GPIO device from the list when it's unregistered")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-25 15:35:40 -08:00
Boerge Struempfel
6df51c525a gpiolib: sysfs: Fix error handling on failed export
[ Upstream commit 95dd1e34ff ]

If gpio_set_transitory() fails, we should free the GPIO again. Most
notably, the flag FLAG_REQUESTED has previously been set in
gpiod_request_commit(), and should be reset on failure.

To my knowledge, this does not affect any current users, since the
gpio_set_transitory() mainly returns 0 and -ENOTSUPP, which is converted
to 0. However the gpio_set_transitory() function calles the .set_config()
function of the corresponding GPIO chip and there are some GPIO drivers in
which some (unlikely) branches return other values like -EPROBE_DEFER,
and -EINVAL. In these cases, the above mentioned FLAG_REQUESTED would not
be reset, which results in the pin being blocked until the next reboot.

Fixes: e10f72bf4b ("gpio: gpiolib: Generalise state persistence beyond sleep")
Signed-off-by: Boerge Struempfel <boerge.struempfel@gmail.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-13 18:45:30 +01:00
Andy Shevchenko
20d9b3b5f2 gpiolib: sysfs: Do unexport GPIO when user asks for it
It seems that sysfs interface implicitly relied on the gpiod_free() to
unexport the line. This is logically incorrect as core gpiolib should
not deal with sysfs so instead of restoring it, let's call
gpiod_unexport() from sysfs code.

Fixes: b0ce9ce408 ("gpiolib: Do not unexport GPIO on freeing")
Reported-by: Marek Behún <kabel@kernel.org>
Closes: https://lore.kernel.org/r/20230808102828.4a9eac09@dellmb
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Marek Behún <kabel@kernel.org>
[Bartosz: tweaked the commit message]
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2023-08-16 13:34:31 +02:00
Linus Torvalds
556eb8b791 Driver core changes for 6.4-rc1
Here is the large set of driver core changes for 6.4-rc1.
 
 Once again, a busy development cycle, with lots of changes happening in
 the driver core in the quest to be able to move "struct bus" and "struct
 class" into read-only memory, a task now complete with these changes.
 
 This will make the future rust interactions with the driver core more
 "provably correct" as well as providing more obvious lifetime rules for
 all busses and classes in the kernel.
 
 The changes required for this did touch many individual classes and
 busses as many callbacks were changed to take const * parameters
 instead.  All of these changes have been submitted to the various
 subsystem maintainers, giving them plenty of time to review, and most of
 them actually did so.
 
 Other than those changes, included in here are a small set of other
 things:
   - kobject logging improvements
   - cacheinfo improvements and updates
   - obligatory fw_devlink updates and fixes
   - documentation updates
   - device property cleanups and const * changes
   - firwmare loader dependency fixes.
 
 All of these have been in linux-next for a while with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the large set of driver core changes for 6.4-rc1.

  Once again, a busy development cycle, with lots of changes happening
  in the driver core in the quest to be able to move "struct bus" and
  "struct class" into read-only memory, a task now complete with these
  changes.

  This will make the future rust interactions with the driver core more
  "provably correct" as well as providing more obvious lifetime rules
  for all busses and classes in the kernel.

  The changes required for this did touch many individual classes and
  busses as many callbacks were changed to take const * parameters
  instead. All of these changes have been submitted to the various
  subsystem maintainers, giving them plenty of time to review, and most
  of them actually did so.

  Other than those changes, included in here are a small set of other
  things:

   - kobject logging improvements

   - cacheinfo improvements and updates

   - obligatory fw_devlink updates and fixes

   - documentation updates

   - device property cleanups and const * changes

   - firwmare loader dependency fixes.

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'driver-core-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (120 commits)
  device property: make device_property functions take const device *
  driver core: update comments in device_rename()
  driver core: Don't require dynamic_debug for initcall_debug probe timing
  firmware_loader: rework crypto dependencies
  firmware_loader: Strip off \n from customized path
  zram: fix up permission for the hot_add sysfs file
  cacheinfo: Add use_arch[|_cache]_info field/function
  arch_topology: Remove early cacheinfo error message if -ENOENT
  cacheinfo: Check cache properties are present in DT
  cacheinfo: Check sib_leaf in cache_leaves_are_shared()
  cacheinfo: Allow early level detection when DT/ACPI info is missing/broken
  cacheinfo: Add arm64 early level initializer implementation
  cacheinfo: Add arch specific early level initializer
  tty: make tty_class a static const structure
  driver core: class: remove struct class_interface * from callbacks
  driver core: class: mark the struct class in struct class_interface constant
  driver core: class: make class_register() take a const *
  driver core: class: mark class_release() as taking a const *
  driver core: remove incorrect comment for device_create*
  MIPS: vpe-cmp: remove module owner pointer from struct class usage.
  ...
2023-04-27 11:53:57 -07:00
Greg Kroah-Hartman
6f14c02220 driver core: create class_is_registered()
Some classes (i.e. gpio), want to know if they have been registered or
not, and poke around in the class's internal structures to try to figure
this out.  Because this is not really a good idea, provide a function
for classes to call to try to figure this out.

Note, this is racy as the state of the class could change at any moment
in time after the call is made, but as usually a class only wants to
know if it has been registered yet or not, it should be fairly safe to
use, and is just as safe as the previous "poke at the class internals"
check was.

Move the gpiolib code to use this function as proof that it works
properly.

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: linux-gpio@vger.kernel.org
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230331093318.82288-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-31 17:44:54 +02:00
Greg Kroah-Hartman
75a2d4226b driver core: class: mark the struct class for sysfs callbacks as constant
struct class should never be modified in a sysfs callback as there is
nothing in the structure to modify, and frankly, the structure is almost
never used in a sysfs callback, so mark it as constant to allow struct
class to be moved to read-only memory.

While we are touching all class sysfs callbacks also mark the attribute
as constant as it can not be modified.  The bonding code still uses this
structure so it can not be removed from the function callbacks.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Russ Weight <russell.h.weight@intel.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steve French <sfrench@samba.org>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-cifs@vger.kernel.org
Cc: linux-gpio@vger.kernel.org
Cc: linux-mtd@lists.infradead.org
Cc: linux-rdma@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: netdev@vger.kernel.org
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230325084537.3622280-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-29 07:54:58 +02:00
Greg Kroah-Hartman
10a03c36b7 drivers: remove struct module * setting from struct class
There is no need to manually set the owner of a struct class, as the
registering function does it automatically, so remove all of the
explicit settings from various drivers that did so as it is unneeded.

This allows us to remove this pointer entirely from this structure going
forward.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313181843.1207845-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-17 15:16:27 +01:00
Andy Shevchenko
380c7ba392 gpiolib: Clean up headers
There is a few things done:
- include only the headers we are direct user of
- when pointer is in use, provide a forward declaration
- add missing headers
- group generic headers and subsystem headers
- sort each group alphabetically

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2023-03-06 12:33:02 +02:00
Arnd Bergmann
d74e316633 gpiolib: remove legacy gpio_export()
There are only a handful of users of gpio_export() and
related functions.

As these are just wrappers around the modern gpiod_export()
helper, remove the wrappers and open-code the gpio_to_desc
in all callers to shrink the legacy API.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2023-03-06 12:33:01 +02:00
Andy Shevchenko
57017edd46 gpiolib: Embed iterator variable into for_each_gpio_desc_with_flag()
The iterator loop is used exclusively to get a descriptor, which in its
turn is what is being used by the caller. Embed the iterator variable
into the loop in the for_each_gpio_desc_with_flag() macro helper.

Suggested-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-04-09 22:37:48 +02:00
Linus Torvalds
ebcb577aee gpio updates for v5.18-rc1
- new driver: gpio-en7523
 - dt-bindings: convertion of faraday,ftgpio010 to YAML, new compatible string
   in gpio-vf610 and a bugfix in an example
 - gpiolib core: several improvements and some code shrink
 - documentation: convert all public docs into kerneldoc format
 - set IRQ bus token in gpio-crystalcove (addresses a debugfs issue)
 - add a missing return value check for kstrdup() in gpio-merrifield
 - allow gpio-tps68470 to be built as module
 - more work on limiting usage of of_node in GPIO drivers
 - several sysfs interface improvements
 - use SDPX in gpio-ts4900
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Merge tag 'gpio-updates-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio updates from Bartosz Golaszewski:
 "Relatively few updates for this release cycle. We have a single new
  driver and some minor changes in drivers, more work on limiting the
  usage of of_node in drivers and DT updates:

   - new driver: gpio-en7523

   - dt-bindings: convertion of faraday,ftgpio010 to YAML, new
     compatible string in gpio-vf610 and a bugfix in an example

   - gpiolib core: several improvements and some code shrink

   - documentation: convert all public docs into kerneldoc format

   - set IRQ bus token in gpio-crystalcove (addresses a debugfs issue)

   - add a missing return value check for kstrdup() in gpio-merrifield

   - allow gpio-tps68470 to be built as module

   - more work on limiting usage of of_node in GPIO drivers

   - several sysfs interface improvements

   - use SDPX in gpio-ts4900"

* tag 'gpio-updates-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
  gpio: ts4900: Use SPDX header
  gpiolib: Use list_first_entry()/list_last_entry()
  gpiolib: sysfs: Simplify edge handling in the code
  gpiolib: sysfs: Move kstrtox() calls outside of the mutex lock
  gpiolib: sysfs: Move sysfs_emit() calls outside of the mutex lock
  gpiolib: make struct comments into real kernel docs
  dt-bindings: gpio: convert faraday,ftgpio01 to yaml
  dt-bindings: gpio: gpio-vf610: Add imx93 compatible string
  gpiolib: Simplify error path in gpiod_get_index() when requesting GPIO
  gpiolib: Use short form of ternary operator in gpiod_get_index()
  gpiolib: Introduce for_each_gpio_desc_with_flag() macro
  gpio: Add support for Airoha EN7523 GPIO controller
  dt-bindings: arm: airoha: Add binding for Airoha GPIO controller
  dt-bindings: gpio: fix gpio-hog example
  gpio: tps68470: Allow building as module
  gpio: tegra: Get rid of duplicate of_node assignment
  gpio: altera-a10sr: Switch to use fwnode instead of of_node
  gpio: merrifield: check the return value of devm_kstrdup()
  gpio: crystalcove: Set IRQ domain bus token to DOMAIN_BUS_WIRED
2022-03-25 12:28:23 -07:00
Andy Shevchenko
667630edb5 gpiolib: sysfs: Simplify edge handling in the code
Instead of keeping specific data structure for IRQ trigger types, switch
to array of trigger names and use index as a type.

The code is in maintenance mode and that array is not going to grow.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-02-16 16:03:08 +01:00
Andy Shevchenko
6b3c1791ae gpiolib: sysfs: Move kstrtox() calls outside of the mutex lock
In a few places we perform kstrtox() operations under mutex that
do not require any locking. Move them outside of the mutex locks.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-02-16 16:02:34 +01:00
Andy Shevchenko
e28747da77 gpiolib: sysfs: Move sysfs_emit() calls outside of the mutex lock
In a few places we perform sysfs_emit() operations under mutex that
do not require any locking. Move them outside of the mutex locks.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-02-16 16:02:11 +01:00
Andy Shevchenko
80c78fbeef gpiolib: Introduce for_each_gpio_desc_with_flag() macro
In a few places we are using a loop against all GPIO descriptors
with a given flag for a given device. Replace it with a consolidated
for_each type of macro.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-02-08 10:35:49 +01:00
Andy Shevchenko
95a4eed7dd gpiolib: Never return internal error codes to user space
Currently it's possible that character device interface may return
the error codes which are not supposed to be seen by user space.
In this case it's EPROBE_DEFER.

Wrap it to return -ENODEV instead as sysfs does.

Fixes: d7c51b47ac ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 61f922db72 ("gpio: userspace ABI for reading GPIO line events")
Fixes: 3c0d9c635a ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Reported-by: Suresh Balakrishnan <suresh.balakrishnan@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-02-08 10:34:15 +01:00
Andy Shevchenko
9e23bf6b00 gpiolib: Use sysfs_emit() in "show" functions
The sysfs_emit() function was introduced to make it less ambiguous
which function is preferred when writing to the output buffer in
a "show" callback [1].

Convert the GPIO library sysfs interface from sprintf() to sysfs_emit()
accordingly, as the latter is aware of the PAGE_SIZE buffer and correctly
returns the number of bytes written into the buffer.

No functional change intended.

[1] Documentation/filesystems/sysfs.rst

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2021-05-21 14:56:10 +02:00
Andy Shevchenko
fd80b8ba3a gpiolib: Make use of assign_bit() API (part 2)
We have for some time the assign_bit() API to replace open coded

	if (foo)
		set_bit(n, bar);
	else
		clear_bit(n, bar);

Use this API in GPIO library code.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2021-05-21 14:53:35 +02:00
Matti Vaittinen
23cf00ddd2 gpio: sysfs: Obey valid_mask
Do not allow exporting GPIOs which are set invalid
by the driver's valid mask.

Fixes: 726cb3ba49 ("gpiolib: Support 'gpio-reserved-ranges' property")
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2021-03-31 20:32:38 +02:00
Andy Shevchenko
8bbff39c6c gpiolib: Unify expectations about ->request() returned value
Half of the code in the GPIO library is written in an expectation that
any non-zero value returned from the ->request() callback is an error code,
while some code checks only for negative values.

Unify expectations about ->request() returned value to be non-zero
for an error and 0 for the success.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-10-26 15:43:15 +01:00
Kent Gibson
ef087d8e95 gpiolib: move gpiolib-sysfs function declarations into their own header
Move gpiolib-sysfs function declarations into their own header.

These functions are in gpiolib-sysfs.c, and are only required by gpiolib.c,
and so should be in a module header, not gpiolib.h.

This brings gpiolib-sysfs into line with gpiolib-cdev, and is another step
towards removing the sysfs inferface.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12 10:22:00 +02:00
Wang Qing
97cd738c44 gpiolib: sysfs: use kobj_to_dev
Use kobj_to_dev() API instead of container_of().

Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-06-15 10:07:49 +02:00
Geert Uytterhoeven
ddd8891e01 gpiolib: Add GPIOCHIP_NAME definition
The string literal "gpiochip" is used in several places.
Add a definition for it, and use it everywhere, to make sure everything
stays in sync.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20191127084253.16356-2-geert+renesas@glider.be
Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2019-12-12 11:36:13 +01:00
Linus Walleij
dae5f0afcf gpio: Use SPDX header for core library
Use the SPDX headers and cut down on boilerplate to indicate the
license in the core gpiolib implementation.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-09-25 09:08:48 +02:00
Linus Walleij
f13a0b0bb4 gpio: Get rid of legacy header
A bunch of core gpiolib files still include the <linux/gpio.h>
legacy API header for no good reason. After this only the
gpiolib-legacy.c file includes it, which is fine.

The sysfs ABI code has a pointless wrapper function around
gpio_to_desc() we can just loose.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-09-17 10:55:24 -07:00
Christophe Leroy
1efba35afa gpio: sysfs: avoid using kstrtol() in 'value' attribute write
A 'perf record' on an app continuously writing in the 'value'
attribute show that most of the time is spent in kstrtol()

--17.99%--value_store
          |
          |--10.17%--kstrtoint
          |          |
          |          |--8.82%--kstrtoll
          |
          |--2.50%--gpiod_set_value_cansleep
          |
          |--1.82%--u16_gpio_set
          |
          |--1.46%--value_store

The normal case is to write 0 or 1 in the attribute, therefore
this patch avoids the call to kstrtol() in the most common cases

Then 'perf record' shows

--7.21%--value_store
          |
          |--2.69%--u16_gpio_set
          |
          |--1.47%--value_store
          |
          |--1.08%--gpiod_set_value_cansleep
          |
          |--0.60%--mutex_lock
          |
           --0.58%--mutex_unlock

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-12-20 10:34:58 +01:00
Christophe Leroy
7a94b88cb7 gpio: sysfs: don't use sprintf() for 'value' attribute
A bench with 'perf record' shows that most of time spent in value_show()
is spent in sprintf()

--42.41%--sysfs_kf_read
          |
          |--39.73%--dev_attr_show
          |          |
          |          |--38.23%--value_show
          |          |          |
          |          |          |--29.22%--sprintf
          |          |          |
          |          |          |--2.94%--gpiod_get_value_cansleep
          |          |          |

value_show() only returns "0\n" or "1\n", therefore the use of
sprintf() can be avoided

With this patch we get the following result with 'perf record'

--13.89%--sysfs_kf_read
          |
          |--10.72%--dev_attr_show
          |          |
          |          |--9.44%--value_show
          |          |          |
          |          |          |--4.61%--gpiod_get_value_cansleep

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-12-20 10:34:01 +01:00
Christophe Leroy
9295c01253 gpio: sysfs: correct error handling on 'value' attribute read.
'value' attribute is supposed to only return 0 or 1 according to
the documentation.
With today's implementation, if gpiod_get_value_cansleep() fails
the printed 'value' is a negative value.

This patch ensures that an error is returned on read instead.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-12-20 10:33:21 +01:00
Christophe Leroy
7fda9100bb gpio: sysfs: change 'value' attribute to prealloc
The GPIO 'value' attribute is time critical. A small bench with
'perf record' on the app below shows that 80% of the time spent in
sysfs_kf_seq_show() is spent in memset() for zeroising the buffer.

|--67.48%--sysfs_kf_seq_show
|          |
|          |--54.40%--memset
|          |
|          |--11.49%--dev_attr_show
|          |          |
|          |          |--10.06%--value_show
|          |          |          |
|          |          |          |--4.75%--sprintf
|          |          |          |          |

This patch changes the attribute type to prealloc, eliminating the
need to zeroise the buffer at each read. 'perf record' gives the
following result.

|--42.41%--sysfs_kf_read
|          |
|          |--39.73%--dev_attr_show
|          |          |
|          |          |--38.23%--value_show
|          |          |          |
|          |          |          |--29.22%--sprintf
|          |          |          |          |

Test done with the following small app:

int main(int argc, char **argv)
{
	int fd = open(argv[1], O_RDONLY);

	for (;;) {
		int buf[512];

		read(fd, buf, 512);
		lseek(fd, 0, SEEK_SET);
	}
	exit(0);
}

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-12-20 10:28:05 +01:00
Andrew Jeffery
e10f72bf4b gpio: gpiolib: Generalise state persistence beyond sleep
General support for state persistence is added to gpiolib with the
introduction of a new pinconf parameter to propagate the request to
hardware. The existing persistence support for sleep is adapted to
include hardware support if the GPIO driver provides it. Persistence
continues to be enabled by default; in-kernel consumers can opt out, but
userspace (currently) does not have a choice.

The *_SLEEP_MAY_LOSE_VALUE and *_SLEEP_MAINTAIN_VALUE symbols are
renamed, dropping the SLEEP prefix to reflect that the concept is no
longer sleep-specific.  I feel that renaming to just *_MAY_LOSE_VALUE
could initially be misinterpreted, so I've further changed the symbols
to *_TRANSITORY and *_PERSISTENT to address this.

The sysfs interface is modified only to keep consistency with the
chardev interface in enforcing persistence for userspace exports.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-12-02 22:42:34 +01:00
Linus Torvalds
70b8e9eb3b This is the bulk of the GPIO changes for the v4.14 cycle:
Core changes
 - Allow the GPIO irqchip to allocate IRQs dynamically. This is
   an important change on systems where only a restricted number
   of IRQs, lesser than the number of GPIO lines, can be utilized.
   Now we can allocate these on a first-come-first-served basis
   instead of hogging up valuable IRQ lines.
 - Serious fix-up of the kerneldoc documentation and inclusion
   into the kerneldoc builds.
 - Pulled in the IRQ simulator from the IRQ core tree and use
   this in the GPIO mockup driver for exhaustive testing of
   interrupt abilities.
 
 New drivers
 - New driver for ThunderX and OCTEON-TX. This is especially
   interesting as it picks up improvements from the IRQ core that
   allow us to handle fasteoi ACKs upwards in a hierarchy when
   there are IRQ flag latches on several levels in a hierarchy.
   Very interesting work here.
 - New subdriver for Renesas R-Car r8a7745 (RZ/G1E).
 
 Misc
 - Several fixes and improvements for Xilinx Zynq GPIO.
 - Support an enablement GPIO for the 74x164 GPIO.
 - Switch a bunch of chips to use devres to allocate irq
   descriptors.
 - A bunch of constification fixes.
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Merge tag 'gpio-v4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO updates from Linus Walleij:
 "This is the bulk of the GPIO changes for the v4.14 cycle.

  Not so much changes this time, phew. David Daney and Bartosz
  Golaszewski did all the really interesting work in infrastructure
  improvement across GPIO and IRQ core, hats off for them and to tglx
  and Marc Z for general help with these patch sets.

  Core changes:

   - Allow the GPIO irqchip to allocate IRQs dynamically. This is an
     important change on systems where only a restricted number of IRQs,
     lesser than the number of GPIO lines, can be utilized. Now we can
     allocate these on a first-come-first-served basis instead of
     hogging up valuable IRQ lines.

   - Serious fix-up of the kerneldoc documentation and inclusion into
     the kerneldoc builds.

   - Pulled in the IRQ simulator from the IRQ core tree and use this in
     the GPIO mockup driver for exhaustive testing of interrupt
     abilities.

  New drivers:

   - New driver for ThunderX and OCTEON-TX. This is especially
     interesting as it picks up improvements from the IRQ core that
     allow us to handle fasteoi ACKs upwards in a hierarchy when there
     are IRQ flag latches on several levels in a hierarchy. Very
     interesting work here.

   - New subdriver for Renesas R-Car r8a7745 (RZ/G1E).

  Misc:

   - Several fixes and improvements for Xilinx Zynq GPIO.

   - Support an enablement GPIO for the 74x164 GPIO.

   - Switch a bunch of chips to use devres to allocate irq descriptors.

   - A bunch of constification fixes"

* tag 'gpio-v4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (63 commits)
  gpio: mockup: remove unused variable gc
  gpio: pl061: constify amba_id
  Revert "gpiolib: request the gpio before querying its direction"
  gpio: twl6040: remove unneeded forward declaration
  gpio: zevio: make gpio_chip const
  gpio: add gpio_add_lookup_tables() to add several tables at once
  gpio: rcar: Add r8a7745 (RZ/G1E) support
  gpio: brcmstb: check return value of gpiochip_irqchip_add()
  MAINTAINERS: Add entry for THUNDERX GPIO Driver.
  gpio: Add gpio driver support for ThunderX and OCTEON-TX
  gpio: mockup: use irq_sim
  gpio: mxs: use devres for irq generic chip
  gpio: mxc: use devres for irq generic chip
  gpio: pch: use devres for irq generic chip
  gpio: ml-ioh: use devres for irq generic chip
  gpio: sta2x11: use devres for irq generic chip
  gpio: sta2x11: disallow unbinding the driver
  gpio: mxs: disallow unbinding the driver
  gpio: mxc: disallow unbinding the driver
  gpio: aspeed: Remove reference to clock name in debounce warning message
  ...
2017-09-05 11:49:48 -07:00
Thierry Reding
2d9d05192e gpio: sysfs: Fixup kerneldoc
Fix up some references to parameters to match the code.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-14 15:01:13 +02:00
Masami Hiramatsu
90b05b0598 gpio: reject invalid gpio before getting gpio_desc
Check user-given gpio number and reject it before
calling gpio_to_desc() because gpio_to_desc() is
for kernel driver and it expects given gpio number
is valid (means 0 to 511).
If given number is invalid, gpio_to_desc() calls
WARN() and dump registers and stack for debug.
This means user can easily kick WARN() just by
writing invalid gpio number (e.g. 512) to
/sys/class/gpio/export.

Fixes: 0e9a5edf5d ("gpio: fix deferred probe detection for legacy API")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-14 15:00:43 +02:00
Greg Kroah-Hartman
d83bb159f4 gpio: use class_groups instead of class_attrs
The class_attrs pointer is long depreciated, and is about to be finally
removed, so move to use the class_groups pointer instead.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: <linux-gpio@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 10:41:00 +02:00
Amitesh Singh
31963eb039 gpio: fix documentation for gpiod_unexport
Both gpio_export and gpio_free APIs are obsolete now.

Signed-off-by: Amitesh Singh <singh.amitesh@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-09-12 14:53:33 +02:00
Bamvor Jian Zhang
d27c17285e gpio: fix abi regression in sysfs
We started to assign the gpio_device as parent for the sysfs
but this changes the expected layout of sysfs. Restore the
previous behaviour.

Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-02-25 16:08:45 +01:00
Linus Walleij
fdeb8e1547 gpio: reflect base and ngpio into gpio_device
Some information about the GPIO chip need to stay around also
after the gpio_chip has been removed and only the gpio_device
persist. The base and ngpio are such things, for example we
don't want a new chip arriving to overlap the number space
of a dangling gpio_device, and the chardev may still query
the device for the number of lines etc.

Note that the code that assigns base and insert gpio_device
into the global list no longer check for a missing gpio_chip:
we respect the number space allocated by any other gpio_device.

As a consequence of the gdev being referenced directly from
the gpio_desc, we need to verify it differently from all
in-kernel API calls that fall through to direct queries to
the gpio_chip vtable: we first check that desc is !NULL, then
that desc->gdev is !NULL, then, if desc->gdev->chip is NULL,
we *BAIL OUT* without any error, so as to manage the case
where operations are requested on a device that is gone.

These checks were non-uniform and partly missing in the past:
so to simplify: create the macros VALIDATE_DESC() that will
return -EINVAL if the desc or desc->gdev is missing and just
0 if the chip is gone, and conversely VALIDATE_DESC_VOID()
for the case where the function does not return an error.
By using these macros, we get warning messages about missing
gdev with reference to the right function in the kernel log.

Despite the macro business this simplifies the code and make
it more readable than if we copy/paste the same descriptor
checking code into all code ABI call sites (IMHO).

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-02-11 20:29:46 +01:00
Linus Walleij
1c3cdb1861 gpio: move descriptors into gpio_device
We need gpio_device to hold the descriptors so that they can
be lifecycled with the struct gpio_device held from userspace.
Move the descriptor array into gpio_device. Also rename it from
"desc" (singularis) to "descs" (pluralis) to reflect the fact
that it is an array.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-02-11 20:29:45 +01:00
Linus Walleij
afbc4f312b gpio: move sysfs mock device to the gpio_device
Since gpio_device is the struct that survives if the backing
gpio_chip is removed, move the sysfs mock device to this state
container so it becomes part of the dangling state of the
GPIO device on removal.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-02-11 18:16:54 +01:00
Linus Walleij
ff2b135922 gpio: make the gpiochip a real device
GPIO chips have been around for years, but were never real devices,
instead they were piggy-backing on a parent device (such as a
platform_device or amba_device) but this was always optional.
GPIO chips could also exist without any device at all, with its
struct device *parent (ex *dev) pointer being set to null.

When sysfs was in use, a mock device would be created, with the
optional parent assigned, or just floating orphaned with NULL
as parent.

If sysfs is active, it will use this device as parent.

We now create a gpio_device struct containing a real
struct device and move the subsystem over to using that. The
list of struct gpio_chip:s is augmented to hold struct
gpio_device:s and we find gpio_chips:s by first looking up
the struct gpio_device.

The struct gpio_device is designed to stay around even if the
gpio_chip is removed, so as to satisfy users in userspace
that need a backing data structure to hold the state of the
session initiated with e.g. a character device even if there is
no physical chip anymore.

From this point on, gpiochips are devices.

Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-02-09 11:03:53 +01:00
Linus Walleij
58383c7842 gpio: change member .dev to .parent
The name .dev in a struct is normally reserved for a struct device
that is let us say a superclass to the thing described by the struct.
struct gpio_chip stands out by confusingly using a struct device *dev
to point to the parent device (such as a platform_device) that
represents the hardware. As we want to give gpio_chip:s real devices,
this is not working. We need to rename this member to parent.

This was done by two coccinelle scripts, I guess it is possible to
combine them into one, but I don't know such stuff. They look like
this:

@@
struct gpio_chip *var;
@@
-var->dev
+var->parent

and:

@@
struct gpio_chip var;
@@
-var.dev
+var.parent

and:

@@
struct bgpio_chip *var;
@@
-var->gc.dev
+var->gc.parent

Plus a few instances of bgpio that I couldn't figure out how
to teach Coccinelle to rewrite.

This patch hits all over the place, but I *strongly* prefer this
solution to any piecemal approaches that just exercise patch
mechanics all over the place. It mainly hits drivers/gpio and
drivers/pinctrl which is my own backyard anyway.

Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Alek Du <alek.du@intel.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-11-19 09:24:35 +01:00
Johan Hovold
cef1717b7f gpio: sysfs: move irq trigger flags to class-device data
Move irq trigger flags, which as sysfs-interface specific, to the class
device data.

This avoids accessing the gpio-descriptor flags field using non-atomic
operations without any locking, and allows for a more clear separation
of the sysfs interface from gpiolib core.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12 10:47:57 +02:00
Johan Hovold
427fdeef50 gpio: sysfs: remove FLAG_SYSFS_DIR
Remove FLAG_SYSFS_DIR, which is sysfs-interface specific, and store it
in the class-device data instead.

Note that the flag is only used during export.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12 10:47:52 +02:00
Johan Hovold
2f323b8567 gpio: sysfs: rename active-low helper
Rename active-low helper using common prefix.

Also remove unnecessary manipulation of value argument.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12 10:47:48 +02:00
Johan Hovold
72eba6f66a gpio: sysfs: fix race between gpiod export and unexport
Make sure to deregister the class device (and release the irq) while
holding the sysfs lock in gpio_unexport to prevent racing with
gpio_export.

Note that this requires the recently introduced per-gpio locking to
avoid a deadlock with the kernfs active protection when waiting for the
attribute operations to drain during deregistration.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12 10:47:44 +02:00
Johan Hovold
6ffcb79714 gpio: sysfs: use per-gpio locking
Add a per-gpio mutex to serialise attribute operations rather than use
one global mutex for all gpios and chips.

Having a single global lock for all gpios in a system adds unnecessary
latency to the sysfs interface, and especially when having gpio
controllers connected over slow buses.

Now that the global gpio-sysfs interrupt table is gone and with per-gpio
data in place, we can easily switch to using a more fine-grained locking
scheme.

Keep the global mutex to serialise the global (class) operations of gpio
export and unexport and chip removal.

Also document the locking assumptions made.

Note that this is also needed to fix a race between gpiod_export and
gpiod_unexport.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12 10:47:39 +02:00
Johan Hovold
56d30ec14c gpio: sysfs: clean up gpiod_export_link locking
Drop unnecessary locking from gpiod_export_link. If the class device has
not already been unregistered, class_find_device returns the ref-counted
class device so there's no need for locking.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12 10:47:35 +02:00
Johan Hovold
e4339ce323 gpio: sysfs: clean up edge_store
Remove goto from success path.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12 10:47:31 +02:00
Johan Hovold
2ec74a9593 gpio: sysfs: split irq allocation and deallocation
Add separate helper functions for irq request and free.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12 10:47:27 +02:00
Johan Hovold
b91e18076f gpio: sysfs: only call irq helper if needed
Only call irq helper if actually reconfiguring interrupt state.

This is a preparatory step in introducing separate gpio-irq request and
free functions.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12 10:47:23 +02:00