summaryrefslogtreecommitdiff
path: root/drivers/gpio/gpiolib-cdev.c
AgeCommit message (Collapse)Author
2020-10-07gpiolib: Disable compat ->read() code in UML caseAndy Shevchenko
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Shevchenko
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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 Gibson
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>