The gpiod_direction_output_raw_commit() function checks if any setter
callback is present before doing anything. As the new GPIO setters with
return values were introduced, make this check also succeed if one is
present.
Fixes: 98ce1eb1fd ("gpiolib: introduce gpio_chip setters that return values")
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Link: https://lore.kernel.org/r/20250411-mdb-gpiolib-setters-fix-v2-1-9611280d8822@bootlin.com
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
We use a notifier to implement the mechanism of informing the user-space
about changes in GPIO line status. We register with the notifier when
the GPIO character device file is opened and unregister when the last
reference to the associated file descriptor is dropped.
Since commit fcc8b637c5 ("gpiolib: switch the line state notifier to
atomic") we use the atomic notifier variant. Atomic notifiers call
rcu_synchronize in atomic_notifier_chain_unregister() which caused a
significant performance regression in some circumstances, observed by
user-space when calling close() on the GPIO device file descriptor.
Replace the atomic notifier with the raw variant and provide
synchronization with a read-write spinlock.
Fixes: fcc8b637c5 ("gpiolib: switch the line state notifier to atomic")
Reported-by: David Jander <david@protonic.nl>
Closes: https://lore.kernel.org/all/20250311110034.53959031@erd003.prtnl/
Tested-by: David Jander <david@protonic.nl>
Tested-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20250311-gpiolib-line-state-raw-notifier-v2-1-138374581e1e@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
During chip registration we should neither check the return value of
gc->get_direction() nor hold the SRCU lock when calling it. The former
is because pin controllers may have pins set to alternate functions and
return errors from their get_direction() callbacks. That's alright - we
should default to the safe INPUT state and not bail-out. The latter is
not needed because we haven't registered the chip yet so there's nothing
to protect against dynamic removal. In fact: we currently hit a lockdep
splat. Revert to calling the gc->get_direction() callback directly and
*not* checking its value.
Fixes: 9d846b1aeb ("gpiolib: check the return value of gpio_chip::get_direction()")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/all/81f890fc-6688-42f0-9756-567efc8bb97a@samsung.com/
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250226-retval-fixes-v2-1-c8dc57182441@linaro.org
Tested-by: Gene C <arch@sapience.com>
Link: https://lore.kernel.org/r/20250311175631.83779-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The valid_mask member of the struct gpio_chip is unconditionally written
by the GPIO core at driver registration. Current documentation does not
mention this but just says the valid_mask is used if it's not NULL. This
lured me to try populating it directly in the GPIO driver probe instead
of using the init_valid_mask() callback. It took some retries with
different bitmaps and eventually a bit of code-reading to understand why
the valid_mask was not obeyed. I could've avoided this trial and error if
the valid_mask was hidden in the struct gpio_device instead of being a
visible member of the struct gpio_chip.
Help the next developer who decides to directly populate the valid_mask
in struct gpio_chip by hiding the valid_mask in struct gpio_device and
keep it internal to the GPIO core.
Suggested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/4547ca90d910d60cab3d56d864d59ddde47a5e93.1741180097.git.mazziesaccount@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The valid_mask member of the struct gpio_chip is unconditionally written
by the GPIO core at driver registration. It shouldn't be directly
populated by drivers. This can be prevented by moving it from the struct
gpio_chip to struct gpio_device, which is internal to the GPIO core.
As a preparatory step, provide a getter function which can be used by
those drivers which need the valid_mask information.
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/026f9d78502eca883bfe3faeb684e23d5d6c5e84.1741180097.git.mazziesaccount@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
When GPIOs were requested the validity of GPIOs were checked only when
the GPIO-chip had the request -callback populated. This made using
masked GPIOs possible.
The GPIO chip driver authors may find it difficult to understand the
relation of enforsing the GPIO validity and the 'request' -callback
because the current documentation for the 'request' callback does not
mention this. It only states:
* @request: optional hook for chip-specific activation, such as
* enabling module power and clock; may sleep
The validity of the GPIO line should be checked whether the driver
provides the 'request' callback or not.
Unconditionally check the GPIO validity when GPIO is being requested.
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/cd5e067b80e1bb590027bc3bfa817e7f794f21c3.1741180097.git.mazziesaccount@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
GPIO drivers are not required to support set_multiple() - the core will
fallback to calling set() for each line if it's missing. Remove the
offending check from gpiochip_set_multiple().
Fixes: 98ce1eb1fd ("gpiolib: introduce gpio_chip setters that return values")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/all/ab3e42c0-70fa-48e0-ac93-ecbffef63507@samsung.com/
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250227152831.59784-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The gpiod_direction_input_nonotify() function is supposed to return zero
if the direction for the pin is input. But instead it accidentally
returns GPIO_LINE_DIRECTION_IN (1) which will be cast into an ERR_PTR()
in gpiochip_request_own_desc(). The callers dereference it and it leads
to a crash.
I changed gpiod_direction_output_raw_commit() just for consistency but
returning GPIO_LINE_DIRECTION_OUT (0) is fine.
Cc: stable@vger.kernel.org
Fixes: 9d846b1aeb ("gpiolib: check the return value of gpio_chip::get_direction()")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/254f3925-3015-4c9d-aac5-bb9b4b2cd2c5@stanley.mountain
[Bartosz: moved the variable declarations to the top of the functions]
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
gpiochip_get() is called only in two places: in gpio_chip_get_value()
and in gpiochip_get_multiple() where the existence of the gc->get()
callback is already checked. It makes sense to unduplicate the check by
moving it one level up the stack.
Fixes: 86ef402d80 ("gpiolib: sanitize the return value of gpio_chip::get()")
Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Closes: https://lore.kernel.org/all/Z7yekJ8uRh8dphKn@black.fi.intel.com/
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250226-retval-fixes-v2-3-c8dc57182441@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
We have existing macros for direction settings so we don't need to rely
on the magic value of 1 in the retval check. Use readable logic that
explicitly says we expect INPUT, OUTPUT or a negative errno and nothing
else in gpiochip_get_direction().
Fixes: e623c4303e ("gpiolib: sanitize the return value of gpio_chip::get_direction()")
Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Closes: https://lore.kernel.org/all/Z7yfTggRrk3K6srs@black.fi.intel.com/
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250226-retval-fixes-v2-2-c8dc57182441@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
During chip registration we should neither check the return value of
gc->get_direction() nor hold the SRCU lock when calling it. The former
is because pin controllers may have pins set to alternate functions and
return errors from their get_direction() callbacks. That's alright - we
should default to the safe INPUT state and not bail-out. The latter is
not needed because we haven't registered the chip yet so there's nothing
to protect against dynamic removal. In fact: we currently hit a lockdep
splat. Revert to calling the gc->get_direction() callback directly and
*not* checking its value.
Fixes: 9d846b1aeb ("gpiolib: check the return value of gpio_chip::get_direction()")
Fixes: e623c4303e ("gpiolib: sanitize the return value of gpio_chip::get_direction()")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/all/81f890fc-6688-42f0-9756-567efc8bb97a@samsung.com/
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250226-retval-fixes-v2-1-c8dc57182441@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Add new variants of the set() and set_multiple() callbacks that have
integer return values allowing to indicate failures to users of the GPIO
consumer API. Until we convert all GPIO providers treewide to using
them, they will live in parallel to the existing ones.
Make sure that providers cannot define both. Prefer the new ones and
only use the old ones as fallback.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250220-gpio-set-retval-v2-5-bc4cfd38dae3@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Make the existing wrapper around gpio_chip::set_multiple() consistent
with the one for gpio_chip::set(): make it return int, add a lockdep
assertion, warn on missing set callback and move the code a bit for
better readability.
Add return value checks in all call places.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250220-gpio-set-retval-v2-4-bc4cfd38dae3@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
We have three places where we dereference the gpio_chip::set() callback.
In order to make it easier to incorporate the upcoming new variant of
this callback (one returning an integer value), wrap it in a helper so
that the dereferencing only happens once.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250220-gpio-set-retval-v2-3-bc4cfd38dae3@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Change the in-kernel consumer interface for GPIOs: make all variants of
value setters that don't have a return value, return a signed integer
instead. That will allow these routines to indicate failures to callers.
This doesn't change the implementation just yet, we'll do it in
subsequent commits.
We need to update the gpio-latch module as it passes the address of
value setters as a function pointer argument and thus cares about its
type.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250220-gpio-set-retval-v2-2-bc4cfd38dae3@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
For consistency with most other code that can access requested
descriptors: read the flags once atomically and then test individual
bits from the helper variable. This avoids any potential discrepancies
should flags change during the debug print.
Link: https://lore.kernel.org/r/20250215100847.30136-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
As per the API contract, the get_direction() callback can only
return 0, 1 or a negative error number. Add a wrapper around the callback
calls that filters out anything else.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-8-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The return value of the direction_input() callback may be propagated to
user-space. As per the API contract it can only return 0 or a negative
error number. Add a wrapper around the callback calls that filters out
anything else.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-7-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The return value of the direction_output() callback may be propagated to
user-space. As per the API contract it can only return 0 or a negative
error number. Add a wrapper around the callback calls that filters out
anything else.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-6-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
As per the API contract, the get_multiple() callback is only allowed to
return 0 or a negative error number. Filter out anything else.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-5-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
As per the API contract, the get() callback is only allowed to return 0,
1 or a negative error number. Add a wrapper around the callback calls
that filters out anything else.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-4-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The return value of the set_config() callback may be propagated to
user-space. If a bad driver returns a positive number, it may confuse
user programs. Tighten the API contract and check for positive numbers
returned by GPIO controllers.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-3-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The return value of the request() callback may be propagated to
user-space. If a bad driver returns a positive number, it may confuse
user programs. Tighten the API contract and check for positive numbers
returned by GPIO controllers.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-2-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
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Merge tag 'v6.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into HEAD
Linux 6.14-rc4
The gpiochip_get_ngpios() can be used in the cases where passed device
is not a provider of the certain property. Use fwnode instead.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Reviewed-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Link: https://lore.kernel.org/r/20250213195621.3133406-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Since commit 9d846b1aeb ("gpiolib: check the return value of
gpio_chip::get_direction()") we check the return value of the
get_direction() callback as per its API contract. Some drivers have been
observed to fail to register now as they may call get_direction() in
gpiochip_add_data() in contexts where it has always silently failed.
Until we audit all drivers, replace the bail-out to a kernel log
warning.
Fixes: 9d846b1aeb ("gpiolib: check the return value of gpio_chip::get_direction()")
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/all/Z7VFB1nST6lbmBIo@finisterre.sirena.org.uk/
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/all/dfe03f88-407e-4ef1-ad30-42db53bbd4e4@samsung.com/
Tested-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250219144356.258635-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Hardware timestamping is only used on tegra186 platforms but we include
the code and export the symbols everywhere. Shrink the binary a bit by
compiling the relevant functions conditionally.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250217103922.151047-2-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
During the locking rework in GPIOLIB, we omitted one important use-case,
namely: setting and getting values for GPIO descriptor arrays with
array_info present.
This patch does two things: first it makes struct gpio_array store the
address of the underlying GPIO device and not chip. Next: it protects
the chip with SRCU from removal in gpiod_get_array_value_complex() and
gpiod_set_array_value_complex().
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250215095655.23152-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
As per the API contract - gpio_chip::get_direction() may fail and return
a negative error number. However, we treat it as if it always returned 0
or 1. Check the return value of the callback and propagate the error
number up the stack.
Cc: stable@vger.kernel.org
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-1-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The gpiochip_get_ngpios() uses chip_*() macros to print messages.
However these macros rely on gpiodev to be initialised and set,
which is not the case when called via bgpio_init(). In such a case
the printing messages will crash on NULL pointer dereference.
Replace chip_*() macros by the respective dev_*() ones to avoid
such crash.
Fixes: 55b2395e4e ("gpio: mmio: handle "ngpios" properly in bgpio_init()")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250213155646.2882324-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Deduplicate gpiod_direction_input_nonotify() call in
gpiod_direction_output_nonotify() when emulating open-drain
or open-source behaviour. It also aligns the error check
approaches in set_output_value and set_output_flag labels.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250204175646.150577-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The one of previous changes modified the library code to use
helpers from string_choices.h. Nevertheless it misses more
opportunities to convert the code. Here is the second part
of the conversion.
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250205112936.575493-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Replace ternary (condition ? "enable" : "disable") syntax with helpers
from string_choices.h because:
1. Simple function call with one argument is easier to read. Ternary
operator has three arguments and with wrapping might lead to quite
long code.
2. Is slightly shorter thus also easier to read.
3. It brings uniformity in the text - same string.
4. Allows deduping by the linker, which results in a smaller binary
file.
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250114191438.857656-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Add the newline separator before generating the gpio chip entry to make
the code easier to read.
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20241028125000.24051-4-johan+linaro@kernel.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Add the missing newline after entries for recently removed gpio chips
so that the chip sections are separated by a newline as intended.
Fixes: e348544f79 ("gpio: protect the list of GPIO devices with SRCU")
Cc: stable@vger.kernel.org # 6.9
Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20241028125000.24051-3-johan+linaro@kernel.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The gpiolib debugfs interface exports a list of all gpio chips in a
system and the state of their pins.
The gpio chip sections are supposed to be separated by a newline
character, but a long-standing bug prevents the separator from
being included when output is generated in multiple sessions, making the
output inconsistent and hard to read.
Make sure to only suppress the newline separator at the beginning of the
file as intended.
Fixes: f9c4a31f61 ("gpiolib: Use seq_file's iterator interface")
Cc: stable@vger.kernel.org # 3.7
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20241028125000.24051-2-johan+linaro@kernel.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
For optional GPIOs we may pass NULL to gpiod_direction_(input|output)().
With the call to the notifier chain added by commit 07c61d4da4
("gpiolib: notify user-space about in-kernel line state changes") we
will now dereference a NULL pointer in this case. The reason for that is
the fact that the expansion of the VALIDATE_DESC() macro (which returns
0 for NULL descriptors) was moved into the nonotify variants of the
direction setters.
Move them back to the top-level interfaces as the nonotify ones are only
ever called from inside the GPIO core and are always passed valid GPIO
descriptors. This way we'll never call the line_state notifier chain
with non-valid descs.
Fixes: 07c61d4da4 ("gpiolib: notify user-space about in-kernel line state changes")
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/all/d6601a31-7685-4b21-9271-1b76116cc483@sirena.org.uk/
Tested-by: Klara Modin <klarasmodin@gmail.com>
Tested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241024133834.47395-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
We currently only notify user-space about line config changes that are
made from user-space. Any kernel config changes are not signalled.
Let's improve the situation by emitting the events closer to the source.
To that end let's call the relevant notifier chain from the functions
setting direction, gpiod_set_config(), gpiod_set_consumer_name() and
gpiod_toggle_active_low(). This covers all the options that we can
inform the user-space about. We ignore events which don't have
corresponding flags exported to user-space on purpose - otherwise the
user would see a config-changed event but the associated line-info would
remain unchanged.
gpiod_direction_output/input() can be called from any context.
Fortunately, we now emit line state events using an atomic notifier
chain, so it's no longer an issue.
Let's also add non-notifying wrappers around the direction setters in
order to not emit superfluous reconfigure events when requesting the
lines as the initial config should be part of the request notification.
Use gpio_do_set_config() instead of gpiod_set_debounce() for configuring
debouncing via hardware from the character device code to avoid multiple
reconfigure events.
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20241018-gpio-notify-in-kernel-events-v5-8-c79135e58a1c@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
With everything else ready, we can now switch to using the atomic
notifier for line state events which will allow us to notify user-space
about direction changes from atomic context.
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20241018-gpio-notify-in-kernel-events-v5-7-c79135e58a1c@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This effectively reverts commits 9344e34e79 ("gpiolib: cdev: relocate
debounce_period_us from struct gpio_desc") and d8543cbaf9 ("gpiolib:
remove debounce_period_us from struct gpio_desc") and goes back to
storing the debounce period in microseconds in the GPIO descriptor
We're doing it in preparation for notifying the user-space about
in-kernel line config changes.
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20241018-gpio-notify-in-kernel-events-v5-3-c79135e58a1c@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
We don't need to guard the GPIO chip until its first dereference in
gpio_do_set_config().
First: change the prototype of gpio_do_set_config() to take the GPIO
line descriptor as argument, then move the gpio_chip protection into it
and drop it in two places where it's done too early.
This has the added benefit of making gpio_go_set_config() safe to use
from outside of this compilation unit without taking the gdev SRCU read
lock and will come in handy when we'll want to make it available to the
character device code.
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20241018-gpio-notify-in-kernel-events-v5-2-c79135e58a1c@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
We notify user-space about lines being requested from user-space or by
drivers calling gpiod_get() but not when drivers request their own lines
so add the missing call to gpiod_line_state_notify().
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20241018-gpio-notify-in-kernel-events-v5-1-c79135e58a1c@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
We currently iterate over the descriptors owned by the GPIO device we're
adding twice with the first loop just setting the gdev pointer. It's not
used anywhere between this and the second loop so just drop the first
one and move the assignment to the second.
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20241004-gpio-notify-in-kernel-events-v1-2-8ac29e1df4fe@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Mathieu Dubois-Briand
Bartosz Golaszewski
Matti Vaittinen
Dan Carpenter
Andy Shevchenko
Krzysztof Kozlowski
Johan Hovold