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* gpiolib: Ensure struct gpio is always definedMark Brown2011-10-24
| | | | | | | | | | | | Currently struct gpio is only defined when using gpiolib which makes the stub gpio_request_array() much less useful in drivers than is ideal as they can't work with struct gpio. Since there are no other definitions in kernel instead make the define always available no matter if gpiolib is selectable or selected, ensuring that drivers can always use the type. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* gpio: add GPIOF_ values regardless on kconfig settingsRandy Dunlap2011-06-16
| | | | | | | | | | | | Make GPIOF_ defined values available even when GPIOLIB nor GENERIC_GPIO is enabled by moving them to <linux/gpio.h>. Fixes these build errors in linux-next: sound/soc/codecs/ak4641.c:524: error: 'GPIOF_OUT_INIT_LOW' undeclared (first use in this function) sound/soc/codecs/wm8915.c:2921: error: 'GPIOF_OUT_INIT_LOW' undeclared (first use in this function) Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* gpio: make gpio_{request,free}_array gpio array parameter constLars-Peter Clausen2011-05-27
| | | | | | | | | | | gpio_{request,free}_array should not (and do not) modify the passed gpio array, so make the parameter const. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Eric Miao <eric.y.miao@gmail.com> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* gpio: Convert gpio_is_valid to return boolJoe Perches2011-05-26
| | | | | | | | | | | | | | Make the code a bit more readable. Instead of casting an int to an unsigned then comparing to MAX_NR_GPIOS, add a >= 0 test and let the compiler optimizer do the conversion to unsigned. The generated code should be the same. Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* include/gpio.h: remove remaining __must_check-annotiationsWolfram Sang2011-01-14
| | | | | | | | | | Commit 5f829e405ec4e96f711165a4a7b55c271d4363e2 (gpiolib: add missing functions to generic fallback) also introduced two. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Cc: Greg KH <gregkh@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Revert "gpiolib: annotate gpio-intialization with __must_check"Linus Torvalds2011-01-13
| | | | | | | | | | | | | | | | | This reverts commit 0fdae42d361bbb431ca0ab0efed5126a94821177, which wasn't really supposed to go in, and causes lots of annoying warnings. Quoth Andrew: "Complete brainfart - I meant to drop that patch ages ago." Quoth Greg: "Ick, yeah, that patch isn't ok to go in as-is, all of the callers need to be fixed up first, which is what I thought we had agreed on..." Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gpiolib: add missing functions to generic fallbackWolfram Sang2011-01-13
| | | | | | | | Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Greg KH <gregkh@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gpiolib: annotate gpio-intialization with __must_checkWolfram Sang2011-01-13
| | | | | | | | | | | | | | Because GPIOs can have crucial functions especially in embedded systems, we are better safe than sorry regarding their configuration. For gpio_request, the documentation is simply enforced: <quote>"The return value of gpio_request() must be checked."</quote> For gpio_direction_* and gpio_request_*, we now act accordingly. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Greg KH <gregkh@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gpiolib: Add 'struct gpio_chip' forward declaration for !GPIOLIB caseAnton Vorontsov2010-09-01
| | | | | | | | | | | | | | | | | | | | | With CONFIG_GPIOLIB=n, the 'struct gpio_chip' is not declared, so the following pops up on PowerPC: cc1: warnings being treated as errors In file included from arch/powerpc/platforms/52xx/mpc52xx_common.c:19: include/linux/of_gpio.h:74: warning: 'struct gpio_chip' declared inside parameter list include/linux/of_gpio.h:74: warning: its scope is only this definition or declaration, which is probably not what you want include/linux/of_gpio.h:75: warning: 'struct gpio_chip' declared inside parameter list make[2]: *** [arch/powerpc/platforms/52xx/mpc52xx_common.o] Error 1 This patch fixes the issue by providing the proper forward declaration. Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* gpiolib: introduce set_debounce methodFelipe Balbi2010-05-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A few architectures, like OMAP, allow you to set a debouncing time for the gpio before generating the IRQ. Teach gpiolib about that. Mark said: : This would be generally useful for embedded systems, especially where : the interrupt concerned is a wake source. It allows drivers to avoid : spurious interrupts from noisy sources so if the hardware supports it : the driver can avoid having to explicitly wait for the signal to become : stable and software has to cope with fewer events. We've lived without : it for quite some time, though. David said: : I looked at adding debounce support to the generic GPIO calls (and thus : gpiolib) some time back, but decided against it. I forget why at this : time (check list archives) but it wasn't because of lack of utility in : certain contexts. : : One thing to watch out for is just how variable the hardware capabilities : are. Atmel GPIOs have something like a fixed number of 32K clock cycles : for debounce, twl4030 had something odd, OMAPs were more like the Atmel : chips but with a different clock. In some cases debouncing had to be : ganged, not per-GPIO. And so forth. Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com> Cc: Tony Lindgren <tony@atomide.com> Cc: David Brownell <david-b@pacbell.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gpiolib: add support for changing value polarity in sysfsJani Nikula2009-12-16
| | | | | | | | | | | | | Drivers may use gpiolib sysfs as part of their public user space interface. The GPIO number and polarity might change from board to board. The gpio_export_link() call can be used to hide the GPIO number from user space. Add support for also hiding the GPIO line polarity changes from user space. Signed-off-by: Jani Nikula <ext-jani.1.nikula@nokia.com> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gpiolib: allow exported GPIO nodes to be named using sysfs linksJani Nikula2009-09-23
| | | | | | | | | | | | | | | | | | Commit 926b663ce8215ba448960e1ff6e58b67a2c3b99b (gpiolib: allow GPIOs to be named) already provides naming on the chip level. This patch provides more flexibility by allowing multiple names where ever in sysfs on a per GPIO basis. Adapted from David Brownell's comments on a similar concept: http://lkml.org/lkml/2009/4/20/203. [randy.dunlap@oracle.com: fix build for CONFIG_GENERIC_GPIO=n] Signed-off-by: Jani Nikula <ext-jani.1.nikula@nokia.com> Acked-by: David Brownell <david-b@pacbell.net> Cc: Daniel Silverstone <dsilvers@simtec.co.uk> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gpio_free might sleep, generic partUwe Kleine-König2008-10-16
| | | | | | | | | | | | | | According to the documentation gpio_free should only be called from task context only. To make this more explicit add a might sleep to all implementations. This is the generic part which changes gpiolib and the fallback implementation only. Signed-off-by: Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gpio: sysfs interfaceDavid Brownell2008-07-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds a simple sysfs interface for GPIOs. /sys/class/gpio /export ... asks the kernel to export a GPIO to userspace /unexport ... to return a GPIO to the kernel /gpioN ... for each exported GPIO #N /value ... always readable, writes fail for input GPIOs /direction ... r/w as: in, out (default low); write high, low /gpiochipN ... for each gpiochip; #N is its first GPIO /base ... (r/o) same as N /label ... (r/o) descriptive, not necessarily unique /ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1) GPIOs claimed by kernel code may be exported by its owner using a new gpio_export() call, which should be most useful for driver debugging. Such exports may optionally be done without a "direction" attribute. Userspace may ask to take over a GPIO by writing to a sysfs control file, helping to cope with incomplete board support or other "one-off" requirements that don't merit full kernel support: echo 23 > /sys/class/gpio/export ... will gpio_request(23, "sysfs") and gpio_export(23); use /sys/class/gpio/gpio-23/direction to (re)configure it, when that GPIO can be used as both input and output. echo 23 > /sys/class/gpio/unexport ... will gpio_free(23), when it was exported as above The extra D-space footprint is a few hundred bytes, except for the sysfs resources associated with each exported GPIO. The additional I-space footprint is about two thirds of the current size of gpiolib (!). Since no /dev node creation is involved, no "udev" support is needed. Related changes: * This adds a device pointer to "struct gpio_chip". When GPIO providers initialize that, sysfs gpio class devices become children of that device instead of being "virtual" devices. * The (few) gpio_chip providers which have such a device node have been updated. * Some gpio_chip drivers also needed to update their module "owner" field ... for which missing kerneldoc was added. * Some gpio_chips don't support input GPIOs. Those GPIOs are now flagged appropriately when the chip is registered. Based on previous patches, and discussion both on and off LKML. A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this merges to mainline. [akpm@linux-foundation.org: a few maintenance build fixes] Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de> Cc: Greg KH <greg@kroah.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gpio: build fixesDavid Brownell2008-05-24
| | | | | | | | | | | | This fixes various gpio-related build errors (mostly potential) reported in part by Russell King and Uwe Kleine-König. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Arnaud Patard <arnaud.patard@rtp-net.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gpio: <linux/gpio.h> and "no GPIO support here" stubsDavid Brownell2008-03-04
Add a <linux/gpio.h> defining fail/warn stubs for GPIO calls on platforms that don't support the GPIO programming interface. That includes the arch-specific implementation glue otherwise. This facilitates a new model for GPIO usage: drivers that can use GPIOs if they're available, but don't require them. One example of such a driver is NAND driver for various FreeScale chips. On platforms update with GPIO support, they can be used instead of a worst-case delay to verify that the BUSY signal is off. (Also includes a couple minor unrelated doc updates.) Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>