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path: root/Documentation/gpio/consumer.txt
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2014-08-29Documentation: gpio: documentation for optional getters functionsAlexandre Courbot
Add a mention about the _optional variants of (devm_)gpiod_get*(). Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-28gpio: add flags argument to gpiod_get*() functionsAlexandre Courbot
The huge majority of GPIOs have their direction and initial value set right after being obtained by one of the gpiod_get() functions. The integer GPIO API had gpio_request_one() that took a convenience flags parameter allowing to specify an direction and value applied to the returned GPIO. This feature greatly simplifies client code and ensures errors are always handled properly. A similar feature has been requested for the gpiod API. Since setting the direction of a GPIO is so often the very next action done after obtaining its descriptor, we prefer to extend the existing functions instead of introducing new functions that would raise the number of gpiod getters to 16 (!). The drawback of this approach is that all gpiod clients need to be updated. To limit the pain, temporary macros are introduced that allow gpiod_get*() to be called with or without the extra flags argument. They will be removed once all consumer code has been updated. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Mark Brown <broonie@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-06-04Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial into next Pull trivial tree changes from Jiri Kosina: "Usual pile of patches from trivial tree that make the world go round" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (23 commits) staging: go7007: remove reference to CONFIG_KMOD aic7xxx: Remove obsolete preprocessor define of: dma: doc fixes doc: fix incorrect formula to calculate CommitLimit value doc: Note need of bc in the kernel build from 3.10 onwards mm: Fix printk typo in dmapool.c modpost: Fix comment typo "Modules.symvers" Kconfig.debug: Grammar s/addition/additional/ wimax: Spelling s/than/that/, wording s/destinatary/recipient/ aic7xxx: Spelling s/termnation/termination/ arm64: mm: Remove superfluous "the" in comment of: Spelling s/anonymouns/anonymous/ dma: imx-sdma: Spelling s/determnine/determine/ ath10k: Improve grammar in comments ath6kl: Spelling s/determnine/determine/ of: Improve grammar for of_alias_get_id() documentation drm/exynos: Spelling s/contro/control/ radio-bcm2048.c: fix wrong overflow check doc: printk-formats: do not mention casts for u64/s64 doc: spelling error changes ...
2014-05-05doc: spelling error changesCarlos Garcia
Fixed multiple spelling errors. Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Carlos E. Garcia <carlos@cgarcia.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-02-07gpio: make gpiod_direction_output take a logical valuePhilipp Zabel
The documentation was not clear about whether gpio_direction_output should take a logical value or the physical level on the output line, i.e. whether the ACTIVE_LOW status would be taken into account. This converts gpiod_direction_output to use the logical level and adds a new gpiod_direction_output_raw for the raw value. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-12-12gpiolib: return -ENOENT if no GPIO mapping existsAlexandre Courbot
Some devices drivers make use of optional GPIO parameters. For such drivers, it is important to discriminate between the case where no GPIO mapping has been defined for the function they are requesting, and the case where a mapping exists but an error occured while resolving it or when acquiring the GPIO. This patch changes the family of gpiod_get() functions such that they will return -ENOENT if and only if no GPIO mapping is defined for the requested function. Other error codes are used when an actual error occured during the GPIO resolution. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-11-25Documentation: gpiolib: document new interfaceAlexandre Courbot
gpiolib now exports a new descriptor-based interface which deprecates the older integer-based one. This patch documents this new interface and also takes the opportunity to brush-up the GPIO documentation a little bit. The new descriptor-based interface follows the same consumer/driver model as many other kernel subsystems (e.g. clock, regulator), so its documentation has similarly been splitted into different files. The content of the former documentation has been reused whenever it made sense; however, some of its content did not apply to the new interface anymore and have this been removed. Likewise, new sections like the mapping of GPIOs to devices have been written from scratch. The deprecated legacy-based documentation is still available, untouched, under Documentation/gpio/gpio-legacy.txt. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>