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path: root/drivers/gpio/gpiolib-sysfs.c
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2017-12-20gpio: sysfs: avoid using kstrtol() in 'value' attribute writeChristophe Leroy1-2/+7
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>
2017-12-20gpio: sysfs: don't use sprintf() for 'value' attributeChristophe Leroy1-1/+3
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>
2017-12-20gpio: sysfs: correct error handling on 'value' attribute read.Christophe Leroy1-1/+5
'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>
2017-12-20gpio: sysfs: change 'value' attribute to preallocChristophe Leroy1-1/+1
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>
2017-12-03gpio: gpiolib: Generalise state persistence beyond sleepAndrew Jeffery1-5/+9
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>
2017-09-05Merge tag 'gpio-v4.14-1' of ↵Linus Torvalds1-4/+4
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 ...
2017-08-14gpio: sysfs: Fixup kerneldocThierry Reding1-4/+4
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>
2017-08-14gpio: reject invalid gpio before getting gpio_descMasami Hiramatsu1-2/+8
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: 0e9a5edf5d01 ("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>
2017-06-09gpio: use class_groups instead of class_attrsGreg Kroah-Hartman1-5/+8
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>
2016-09-12gpio: fix documentation for gpiod_unexportAmitesh Singh1-2/+2
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>
2016-02-25gpio: fix abi regression in sysfsBamvor Jian Zhang1-1/+11
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>
2016-02-11gpio: reflect base and ngpio into gpio_deviceLinus Walleij1-6/+6
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>
2016-02-11gpio: move descriptors into gpio_deviceLinus Walleij1-1/+1
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>
2016-02-11gpio: move sysfs mock device to the gpio_deviceLinus Walleij1-11/+12
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>
2016-02-09gpio: make the gpiochip a real deviceLinus Walleij1-5/+7
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>
2015-11-19gpio: change member .dev to .parentLinus Walleij1-2/+3
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>
2015-05-12gpio: sysfs: move irq trigger flags to class-device dataJohan Hovold1-23/+24
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>
2015-05-12gpio: sysfs: remove FLAG_SYSFS_DIRJohan Hovold1-8/+7
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>
2015-05-12gpio: sysfs: rename active-low helperJohan Hovold1-2/+2
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>
2015-05-12gpio: sysfs: fix race between gpiod export and unexportJohan Hovold1-25/+26
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>
2015-05-12gpio: sysfs: use per-gpio lockingJohan Hovold1-18/+34
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>
2015-05-12gpio: sysfs: clean up gpiod_export_link lockingJohan Hovold1-20/+8
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>
2015-05-12gpio: sysfs: clean up edge_storeJohan Hovold1-5/+7
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>
2015-05-12gpio: sysfs: split irq allocation and deallocationJohan Hovold1-37/+37
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>
2015-05-12gpio: sysfs: only call irq helper if neededJohan Hovold1-5/+14
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>
2015-05-12gpio: sysfs: clean up interrupt-interface implementationJohan Hovold1-36/+18
Store the value sysfs entry in the gpiod data rather than in a global table accessed through an index stored in the overloaded gpio-descriptor flag field. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: sysfs: remove redundant gpio-descriptor parametersJohan Hovold1-13/+11
Remove redundant gpio-descriptor parameters from sysfs_set_active_low and gpio_setup_irq. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: sysfs: add gpiod class-device dataJohan Hovold1-16/+46
Add gpiod class-device data. This is a first step in getting rid of the insane gpio-descriptor flag overloading, backward irq-interface implementation, and course grained sysfs-interface locking (a single static mutex for every operation on all exported gpios in a system). Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: sysfs: remove redundant export testsJohan Hovold1-51/+23
The attribute operations will never be called for an unregistered device so remove redundant checks for FLAG_EXPORT. Note that kernfs will also guarantee that any active sysfs operation has finished before the attribute is removed 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>
2015-05-12gpio: sysfs: release irq after class-device deregistrationJohan Hovold1-1/+5
Make sure to release any irq only after the class device has been deregistered. This avoids a race between gpiod_unexport and edge_store, where an irq could be allocated just before the gpio class device is deregistered without relying on FLAG_EXPORT and the global sysfs lock. Note that there is no need to hold the sysfs lock when releasing the irq after the class device is gone as kernfs will prevent further attribute operations. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: sysfs: use DEVICE_ATTR macrosJohan Hovold1-25/+18
Use DEVICE_ATTR_RO and DEVICE_ATTR_RW rather than specifying masks and callbacks directly. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: remove gpiod_sysfs_set_active_lowJohan Hovold1-46/+2
Remove gpiod_sysfs_set_active_low (and gpio_sysfs_set_active_low) which allowed code to change the polarity of a gpio line even after it had been exported through sysfs. Drivers should not care, and generally does not know, about gpio-line polarity which is a hardware feature that needs to be described by firmware. It is currently possible to define gpio-line polarity in device-tree and acpi firmware or using platform data. Userspace can also change the polarity through sysfs. Note that drivers using the legacy gpio interface could still use GPIOF_ACTIVE_LOW to change the polarity before exporting the gpio. There are no in-kernel users of this interface. Cc: Jonathan Corbet <corbet@lwn.net> Cc: Harry Wei <harryxiyou@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-doc@vger.kernel.org Cc: linux-kernel@zh-kernel.org Cc: linux-arch@vger.kernel.org Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: sysfs: rename gpiochip registration functionsJohan Hovold1-7/+9
Rename the gpio-chip export/unexport functions to the more descriptive names gpiochip_sysfs_register and gpiochip_sysfs_unregister. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: sysfs: clean up chip class-device handlingJohan Hovold1-26/+13
Clean gpio-chip class device registration and deregistration. The class device is registered when a gpio-chip is added (or from gpiolib_sysfs_init post-core init call), and deregistered when the chip is removed. Store the class device in struct gpio_chip directly rather than do a class-device lookup on deregistration. This also removes the need for the exported flag. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: sysfs: reduce gpiochip-export locking scopeJohan Hovold1-3/+4
Reduce scope of sysfs_lock protection during chip export and unexport, which is only needed to prevent gpiod (re-)exports during chip removal. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: sysfs: preparatory clean upsJohan Hovold1-4/+4
Put the recently introduced gpio-chip pointer to some more use in gpiod_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>
2015-05-12gpio: sysfs: fix redundant lock-as-irq handlingJohan Hovold1-7/+15
Drivers should call gpiochip_lock_as_irq (which prevents the pin direction from being changed) in their irq_request_resources callbacks but some drivers currently fail to do so. Instead a second, explicit and often redundant call to lock-as-irq is made by the sysfs-interface implementation after an irq has been requested. Move the explicit call before the irq-request to match the unlock done after the irq is later released. Note that this also fixes an irq leak, should the explicit call ever have failed. Also add a comment about removing the redundant call once the broken drivers have been fixed. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-04-30gpio: sysfs: fix memory leaks and device hotplugJohan Hovold1-0/+19
Unregister GPIOs requested through sysfs at chip remove to avoid leaking the associated memory and sysfs entries. The stale sysfs entries prevented the gpio numbers from being exported when the gpio range was later reused (e.g. at device reconnect). This also fixes the related module-reference leak. Note that kernfs makes sure that any on-going sysfs operations finish before the class devices are unregistered and that further accesses fail. The chip exported flag is used to prevent gpiod exports during removal. This also makes it harder to trigger, but does not fix, the related race between gpiochip_remove and export_store, which is really a race with gpiod_request that needs to be addressed separately. Also note that this would prevent the crashes (e.g. NULL-dereferences) at reconnect that affects pre-3.18 kernels, as well as use-after-free on operations on open attribute files on pre-3.14 kernels (prior to kernfs). Fixes: d8f388d8dc8d ("gpio: sysfs interface") Cc: stable <stable@vger.kernel.org> # v2.6.27: 01cca93a9491 Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-30gpio: sysfs: fix memory leak in gpiod_sysfs_set_active_lowJohan Hovold1-1/+1
Fix memory leak in the gpio sysfs interface due to failure to drop reference to device returned by class_find_device when setting the gpio-line polarity. Fixes: 0769746183ca ("gpiolib: add support for changing value polarity in sysfs") Cc: stable <stable@vger.kernel.org> # v2.6.33 Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-30gpio: sysfs: fix memory leak in gpiod_export_linkJohan Hovold1-0/+1
Fix memory leak in the gpio sysfs interface due to failure to drop reference to device returned by class_find_device when creating a link. Fixes: a4177ee7f1a8 ("gpiolib: allow exported GPIO nodes to be named using sysfs links") Cc: stable <stable@vger.kernel.org> # v2.6.32 Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-15gpio: sysfs: fix gpio attribute-creation raceJohan Hovold1-22/+39
Fix attribute-creation race with userspace by using the default group to create also the contingent gpio device attributes. Fixes: d8f388d8dc8d ("gpio: sysfs interface") Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-15gpio: sysfs: fix gpio device-attribute leakJohan Hovold1-15/+13
The gpio device attributes were never destroyed when the gpio was unexported (or on export failures). Use device_create_with_groups() to create the default device attributes of the gpio class device. Note that this also fixes the attribute-creation race with userspace for these attributes. Remove contingent attributes in export error path and on unexport. Fixes: d8f388d8dc8d ("gpio: sysfs interface") Cc: stable <stable@vger.kernel.org> # v2.6.27+ Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-15gpio: sysfs: fix gpio-chip device-attribute leakJohan Hovold1-11/+8
The gpio-chip device attributes were never destroyed when the device was removed. Fix by using device_create_with_groups() to create the device attributes of the chip class device. Note that this also fixes the attribute-creation race with userspace. Fixes: d8f388d8dc8d ("gpio: sysfs interface") Cc: stable <stable@vger.kernel.org> # v2.6.27+ Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-11-28gpio: remove const modifier from gpiod_get_direction()Alexandre Courbot1-1/+1
Although gpiod_get_direction() can be considered side-effect free for consumers, its internals involve setting or clearing bits in the affected GPIO descriptor, for which we need to force-cast the const descriptor variable to non-const. This could lead to incorrect behavior if the compiler decides to optimize here, so remove this const attribute. The intent is to make gpiod_get_direction() private anyway, so it does not really matter. Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-10-28gpio: rename gpio_lock_as_irq to gpiochip_lock_as_irqAlexandre Courbot1-2/+2
This function actually operates on a gpio_chip, so its prefix should reflect that fact for consistency with other functions defined in gpio/driver.h. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-24gpio: remove useless check in gpiolib_sysfs_init()Alexandre Courbot1-1/+1
An iterator variable cannot be NULL in its loop. Reported-by: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-23gpio: remove gpiod_lock/unlock_as_irq()Alexandre Courbot1-2/+2
gpio_lock/unlock_as_irq() are working with (chip, offset) arguments and are thus not using the old integer namespace. Therefore, there is no reason to have gpiod variants of these functions working with descriptors, especially since the (chip, offset) tuple is more suitable to the users of these functions (GPIO drivers, whereas GPIO descriptors are targeted at GPIO consumers). Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-23gpio: simplify gpiochip_export()Alexandre Courbot1-11/+9
For some reason gpiochip_export() would invalidate all the descriptors of a chip if exporting it to sysfs failed. This does not appear as necessary. Remove that part of the code. While we are at it, add a note about the non-safety of temporarily releasing a spinlock in the middle of the loop that protects its iterator, and explain why this is done. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-09gpio: move sysfs support to its own fileAlexandre Courbot1-0/+829
sysfs support is currently entangled within the core GPIO support, while it should relly just be a (privileged) user of the integer GPIO API. This patch is a first step towards making the gpiolib code more readable by splitting it into logical parts. Move all sysfs support to their own source file, and share static members of gpiolib that need to be in the private gpiolib.h file. In the future we will want to put some of them back into gpiolib.c, but this first patch let us at least identify them. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-23 14:12:48 +0300