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2014-08-29Documentation: gpio: documentation for optional getters functionsAlexandre Courbot1-1/+23
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 Courbot1-6/+20
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>
2014-07-28gpio: split gpiod board registration into machine headerLinus Walleij1-1/+1
As per example from the regulator subsystem: put all defines and functions related to registering board info for GPIO descriptors into a separate <linux/gpio/machine.h> header. Cc: Andrew Victor <linux@maxim.org.za> Cc: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Thierry Reding <thierry.reding@gmail.com> Acked-by: Stephen Warren <swarren@wwwdotorg.org> Reviewed-by: Alexandre Courbot <gnurou@gmail.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-24gpiolib: Export gpiochip_request_own_desc and gpiochip_free_own_descGuenter Roeck1-0/+21
Both functions were introduced to let gpio drivers request their own gpio pins. Without exporting the functions, this can however only be used by gpio drivers built into the kernel. Secondary impact is that the functions can not currently be used by platform initialization code associated with the gpio-pca953x driver. This code permits auto-export of gpio pins through platform data, but if this functionality is used, the module can no longer be unloaded due to the problem solved with the introduction of gpiochip_request_own_desc and gpiochip_free_own_desc. Export both function so they can be used from modules and from platform initialization code. Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> 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>
2014-06-04Merge branch 'for-linus' of ↵Linus Torvalds1-1/+1
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 Garcia1-1/+1
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>
2014-04-28gpio: document gpio irqchips a bit more, describe helpersLinus Walleij1-0/+59
This adds some documentation about the GPIO irqchips, what types exist etc. Acked-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-02-07gpio: make gpiod_direction_output take a logical valuePhilipp Zabel1-0/+1
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>
2014-02-03gpio: document how to make combined GPIO+irqchip driversLinus Walleij1-0/+35
Write a few words on how GPIO drivers supplying an irqchip should be written. Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-12-12gpiolib: return -ENOENT if no GPIO mapping existsAlexandre Courbot1-1/+5
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>
2013-12-09gpio: better lookup method for platform GPIOsAlexandre Courbot1-11/+17
Change the format of the platform GPIO lookup tables to make them less confusing and improve lookup efficiency. The previous format was a single linked-list that required to compare the device name and function ID of every single GPIO defined for each lookup. Switch that to a list of per-device tables, so that the lookup can be done in two steps, omitting the GPIOs that are not relevant for a particular device. The matching rules are now defined as follows: - The device name must match *exactly*, and can be NULL for GPIOs not assigned to a particular device, - If the function ID in the lookup table is NULL, the con_id argument of gpiod_get() will not be used for lookup. However, if it is defined, it must match exactly. - The index must always match. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-12-03Documentation: gpiolib: add 00-INDEX fileAlexandre Courbot1-0/+14
Give a short overview of the various GPIO documentation files. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-11-25Documentation: gpiolib: document new interfaceAlexandre Courbot6-0/+1436
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>