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path: root/drivers/gpio/gpiolib-cdev.c
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2021-01-27gpiolib: cdev: clear debounce period if line set to outputKent Gibson1-0/+2
When set_config changes a line from input to output debounce is implicitly disabled, as debounce makes no sense for outputs, but the debounce period is not being cleared and is still reported in the line info. So clear the debounce period when the debouncer is stopped in edge_detector_stop(). Fixes: 65cff7046406 ("gpiolib: cdev: support setting debounce") Cc: stable@vger.kernel.org Signed-off-by: Kent Gibson <warthog618@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2021-01-03gpiolib: cdev: fix frame size warning in gpio_ioctl()Kent Gibson1-72/+73
The kernel test robot reports the following warning in [1]: drivers/gpio/gpiolib-cdev.c: In function 'gpio_ioctl': >>drivers/gpio/gpiolib-cdev.c:1437:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=] Refactor gpio_ioctl() to handle each ioctl in its own helper function and so reduce the variables stored on the stack to those explicitly required to service the ioctl at hand. The lineinfo_get_v1() helper handles both the GPIO_GET_LINEINFO_IOCTL and GPIO_GET_LINEINFO_WATCH_IOCTL, as per the corresponding v2 implementation - lineinfo_get(). [1] https://lore.kernel.org/lkml/202012270910.VW3qc1ER-lkp@intel.com/ Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Kent Gibson <warthog618@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-12-09Merge tag 'gpio-updates-for-v5.11' of ↵Linus Walleij1-11/+22
git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux into devel gpio updates for v5.11-rc1 - several refactoring patches of the core gpiolib code - add support for NXP PCAL9554B/C to gpio-pca953x - allow probing mockup devices from device tree - refactoring and improvements to gpio-rcar - improvements to locking in gpio-tegra - code shrink in gpiolib devres - get the irq offset from device tree in gpio-sifive - major refactoring of gpio-exar - convert gpio-mvebu pwm access to regmap - create a new submenu for virtual GPIO drivers - fix clang fall-through warnings treewide - minor driver refactoring and tweaks sprinkled all over
2020-12-09gpiolib: cdev: Flag invalid GPIOs as usedMarc Zyngier1-0/+1
When reporting the state of a GPIO to userspace, we never check for the actual validity of the line, meaning we report invalid lines as being usable. A subsequent request will fail though, which is an inconsistent behaviour from a userspace perspective. Instead, let's check for the validity of the line and report it as used if it is invalid. This allows a tool such as gpioinfo to report something sensible: gpiochip3 - 4 lines: line 0: unnamed unused input active-high line 1: unnamed kernel input active-high [used] line 2: unnamed kernel input active-high [used] line 3: unnamed unused input active-high In this example, lines 1 and 2 are invalid, and cannot be used by userspace. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20201204164739.781812-2-maz@kernel.org Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2020-12-05gpiolib: cdev: allow edge event timestamps to be configured as REALTIMEKent Gibson1-3/+18
Using CLOCK_REALTIME as the source for event timestamps is crucial for some specific applications, particularly those requiring timetamps relative to a PTP clock, so provide an option to switch the event timestamp source from the default CLOCK_MONOTONIC to CLOCK_REALTIME. Note that CLOCK_REALTIME was the default source clock for GPIO until Linux 5.7 when it was changed to CLOCK_MONOTONIC due to issues with the shifting of the realtime clock. Providing this option maintains the CLOCK_MONOTONIC as the default, while also providing a path forward for those dependent on the pre-5.7 behaviour. Suggested-by: Jack Winch <sunt.un.morcov@gmail.com> Signed-off-by: Kent Gibson <warthog618@gmail.com> Link: https://lore.kernel.org/r/20201014231158.34117-2-warthog618@gmail.com Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2020-10-30gpiolib: cdev: add GPIO_V2_LINE_FLAG_EDGE_BOTH and use it in edge_irq_thread()Kent Gibson1-2/+3
Add GPIO_V2_LINE_FLAG_EDGE_BOTH macro and use it in edge_irq_thread() to improve readability of edge handling cases. Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-10-28gpiolib: Switch to use compat_need_64bit_alignment_fixup() helperAndy Shevchenko1-16/+8
Use the new compat_need_64bit_alignment_fixup() helper to avoid ugly ifdeffery in IOCTL compatibility code. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Kent Gibson <warthog618@gmail.com> Depends-on: 527c412519eb ("compat: add a compat_need_64bit_alignment_fixup() helper") Link: https://lore.kernel.org/r/20201014103315.82662-1-andriy.shevchenko@linux.intel.com Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2020-10-26gpiolib: cdev: document that line eflags are sharedKent Gibson1-11/+21
The line.eflags field is shared so document this fact and highlight it throughout using READ_ONCE() and WRITE_ONCE() accessors. Also use a local copy of the eflags in edge_irq_thread() to ensure consistent control flow even if eflags changes. This is only a defensive measure as edge_irq_thread() is currently disabled when the eflags are changed. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-10-13Merge tag 'gpio-v5.10-1' of ↵Linus Torvalds1-53/+1261
git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio Pull GPIO updates from Linus Walleij: "This time very little driver changes but lots of core changes. We have some interesting cooperative work for ARM and Intel alike, making the GPIO subsystem more and more suitable for industrial systems and the like, in addition to the in-kernel users. We touch driver core (device properties) and lib/* by adding one simple string array free function, these are authored by Andy Shevchenko who is a well known and recognized core helpers maintainers so this should be fine. We also see some Android GKI-related modularization in the MXC drivers. Core changes: - The big core change is the updated (v2) userspace character device API. This corrects badly designed 64-bit alignment around the line events. We also add the debounce request feature. This echoes the often quotes passage from Frederick Brooks "The mythical man-month" to always throw one away, which we have seen before in things such as V4L2. So we put in a new one and deprecate and obsolete the old one. - All example tools in tools/gpio/* are migrated to the new API to set a good example. The libgpiod userspace library has been augmented to use this new API pretty much from day 1. - Some misc API hardening by using strn* function calls has been added as well. - Use the simpler IDA interface for GPIO chip instance enumeration. - Add device core function for counting string arrays in device properties. - Provide a generic library function kfree_strarray() that can be used throughout the kernel. Driver enhancements: - The DesignWare dwapb-gpio driver has been enhanced and now uses the IRQ handling in the gpiolib core. - The mockup and aggregator drivers have seen some substantial code clean-up and now use more of the core kernel inftrastructure. - Misc cleanups using dev_err_probe(). - The MXC drivers (Freescale/NXP) can now be built modularized, which makes modularized GKI Android kernels happy" * tag 'gpio-v5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (73 commits) gpiolib: Update header block in gpiolib-cdev.h gpiolib: cdev: switch from kstrdup() to kstrndup() docs: gpio: add a new document to its index.rst gpio: pca953x: Add support for the NXP PCAL9554B/C tools: gpio: add debounce support to gpio-event-mon tools: gpio: add multi-line monitoring to gpio-event-mon tools: gpio: port gpio-event-mon to v2 uAPI tools: gpio: port gpio-hammer to v2 uAPI tools: gpio: rename nlines to num_lines tools: gpio: port gpio-watch to v2 uAPI tools: gpio: port lsgpio to v2 uAPI gpio: uapi: document uAPI v1 as deprecated gpiolib: cdev: support setting debounce gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL gpiolib: cdev: support edge detection for uAPI v2 gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL gpiolib: add build option for CDEV v1 ABI gpiolib: make cdev a build option ...
2020-10-08gpiolib: cdev: switch from kstrdup() to kstrndup()Kent Gibson1-14/+13
Use kstrndup() to copy line labels from the userspace provided char array, rather than ensuring the char array contains a null terminator and using kstrdup(). Note that the length provided to kstrndup() still assumes that the char array does contain a null terminator, so the maximum string length is one less than the array. This is consistent with the previous behaviour. Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Kent Gibson <warthog618@gmail.com> Link: https://lore.kernel.org/r/20201005070246.20927-1-warthog618@gmail.com Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2020-10-07gpiolib: Disable compat ->read() code in UML caseAndy Shevchenko1-1/+1
It appears that UML (arch/um) has no compat.h header defined and hence can't compile a recently provided piece of code in GPIO library. Disable compat ->read() code in UML case to avoid compilation errors. While at it, use pattern which is already being used in the kernel elsewhere. Fixes: 5ad284ab3a01 ("gpiolib: Fix line event handling in syscall compatible mode") Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20201005131044.87276-1-andriy.shevchenko@linux.intel.com Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2020-09-30gpiolib: cdev: support setting debounceKent Gibson1-10/+237
Add support for setting debounce on a line via the GPIO uAPI. Where debounce is not supported by hardware, a software debounce is provided. The implementation of the software debouncer waits for the line to be stable for the debounce period before determining if a level change, and a corresponding edge event, has occurred. This provides maximum protection against glitches, but also introduces a debounce_period latency to edge events. The software debouncer is integrated with the edge detection as it utilises the line interrupt, and integration is simpler than getting the two to interwork. Where software debounce AND edge detection is required, the debouncer provides both. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-09-30gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTLKent Gibson1-0/+61
Add support for the GPIO_V2_LINE_SET_VALUES_IOCTL. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-09-30gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTLKent Gibson1-0/+88
Add support for GPIO_V2_LINE_SET_CONFIG_IOCTL, the uAPI v2 line set config ioctl. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-09-30gpiolib: cdev: support edge detection for uAPI v2Kent Gibson1-0/+277
Add support for edge detection to lines requested using GPIO_V2_GET_LINE_IOCTL. The edge_detector implementation is based on the v1 lineevent implementation. Unlike the v1 implementation, an overflow of the event buffer results in discarding older events, rather than the most recent, so the final event in a burst will correspond to the current state of the line. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-09-30gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and ↵Kent Gibson1-28/+168
GPIO_V2_GET_LINEINFO_WATCH_IOCTL Add support for GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL. The core of this change is the event kfifo switching to contain struct gpioline_info_changed_v2, instead of v1 as v2 is richer. The two uAPI versions are mostly independent - other than where they both provide line info changes via reads on the chip fd. As the info change structs differ between v1 and v2, the infowatch implementation tracks which version of the infowatch ioctl, either GPIO_GET_LINEINFO_WATCH_IOCTL or GPIO_V2_GET_LINEINFO_WATCH_IOCTL, initiates the initial watch and returns the corresponding info change struct to the read. The version supported on that fd locks to that version on the first watch request, so subsequent watches from that process must use the same uAPI version. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-09-30gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTLKent Gibson1-0/+424
Add support for requesting lines using the GPIO_V2_GET_LINE_IOCTL, and returning their current values using GPIO_V2_LINE_GET_VALUES_IOCTL. The struct linereq implementation is based on the v1 struct linehandle implementation. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-09-30gpiolib: cdev: replace strncpy() with strscpy()Kent Gibson1-16/+7
Replace usage of strncpy() with strscpy() to remove -Wstringop-truncation warnings. The structures being populated are zeroed, to prevent stack leakage as they are returned to userspace, so strscpy() performs the equivalent function without the warnings. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Kent Gibson <warthog618@gmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-09-30gpiolib: cdev: gpio_desc_to_lineinfo() should set info offsetKent Gibson1-1/+2
Set the value of the line info offset in gpio_desc_to_lineinfo(), rather than relying on it being passed in the info. This makes the function behave as you would expect from the name - it generates the line info corresponding to a given GPIO desc. Signed-off-by: Kent Gibson <warthog618@gmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-09-17gpiolib: Fix line event handling in syscall compatible modeAndy Shevchenko1-4/+30
The introduced line event handling ABI in the commit 61f922db7221 ("gpio: userspace ABI for reading GPIO line events") missed the fact that 64-bit kernel may serve for 32-bit applications. In such case the very first check in the lineevent_read() will fail due to alignment differences. To workaround this introduce lineevent_get_size() helper which returns actual size of the structure in user space. Fixes: 61f922db7221 ("gpio: userspace ABI for reading GPIO line events") Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Tested-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: refactor lineevent cleanup into lineevent_freeKent Gibson1-23/+21
Consolidate the cleanup of lineevents, currently duplicated in lineevent_create and lineevent_release, into a helper function lineevent_free. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: refactor linehandle cleanup into linehandle_freeKent Gibson1-20/+19
Consolidate the cleanup of linehandles, currently duplicated in linehandle_create and linehandle_release, into a helper function linehandle_free. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: remove recalculation of offsetKent Gibson1-13/+7
Remove recalculation of offset from desc, where desc itself was calculated from offset. There is no benefit from the desc -> hwgpio conversion in this context. The only implicit benefit of the offset -> desc -> hwgpio is the range check in the offset -> desc, but where desc is required you still get that, and where desc isn't required it is simpler to perform the range check directly. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: fix minor race in GET_LINEINFO_WATCHKent Gibson1-5/+5
Merge separate usage of test_bit/set_bit into test_and_set_bit to remove the possibility of a race between the test and set. Similarly test_bit and clear_bit. In the existing code it is possible for two threads to race past the test_bit and then set or clear the watch bit, and neither return EBUSY. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: rename priv to cdevKent Gibson1-45/+45
Rename priv to cdev to improve readability. The name "priv" indicates that the object is pointed to by file->private_data, not what the object is actually is. As it is always used to point to a struct gpio_chardev_data, renaming it to cdev is more appropriate. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: use blocking notifier call chain instead of atomicKent Gibson1-12/+12
Replace usage of atomic_notifier_call_chain with blocking_notifier_call_chain as the notifier function, lineinfo_changed_notify, calls gpio_desc_to_lineinfo, which calls pinctrl_gpio_can_use_line, which can sleep. The chain isn't being called from an atomic context so the the blocking notifier is a suitable substitute. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: remove pointless decrement of iKent Gibson1-2/+0
Remove pointless decrement of variable, and associated comment. While i is used subsequently, it is re-initialized so this decrement serves no purpose. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: rename numdescs to num_descsKent Gibson1-10/+10
Rename numdescs to num_descs to be more consistent with the naming of other counters and improve readability. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: rename 'filep' and 'filp' to 'file' to be consistent with ↵Kent Gibson1-35/+35
other use Rename 'filep' and 'filp' to 'file' to be consistent with other use and improve readability. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: refactor gpiohandle_flags_to_desc_flagsKent Gibson1-41/+19
Refactor the mapping from handle flags to desc flags into a helper function. The assign_bit is overkill where it is replacing the set_bit cases, as is rechecking bits known to be clear in some circumstances, but the DRY simplification more than makes up for any performance degradation, especially as this is not a hot path. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: minor indentation fixesKent Gibson1-14/+14
Make indentation consistent with other use to improve readability. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-07-12gpiolib: cdev: sort includesKent Gibson1-11/+11
Sort the includes of gpiolib-cdev.c to make it easier to identify if a module is included and to avoid duplication. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-06-20gpiolib: split character device into gpiolib-cdevKent Gibson1-0/+1154
Split the cdev specific functionality out of gpiolib.c and into gpiolib-cdev.c. This improves the readability and maintainability of both the cdev and core gpiolib code. Suggested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Kent Gibson <warthog618@gmail.com> Link: https://lore.kernel.org/r/20200616093615.5167-1-warthog618@gmail.com Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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