- Merged the GPIO descriptor API from Alexandre Courbot.
This is a first step toward trying to get rid of the
global GPIO numberspace for the future.
- Add an API so that driver can flag that a certain GPIO
line is being used by a irqchip backend for generating
IRQs, so that we can enforce checks, like not allowing
users to switch that line to an output at runtime, since
this makes no sense. Implemented corresponding calls
in a few select drivers.
- ACPI GPIO cleanups, refactorings and switch to using the
descriptor-based interface.
- Support for the TPS80036 Palmas GPIO variant.
- A new driver for the Broadcom Kona GPIO SoC IP block.
- Device tree support for the PCF857x driver.
- A set of ARM GPIO refactorings with the goal of getting
rid of a bunch of custom GPIO implementations from the
arch/arm/* tree:
- Move the IOP GPIO driver to the GPIO subsystem and
fix all users to use the gpiolib API for accessing
GPIOs. Delete the old custom GPIO implementation.
- Delete the unused custom PXA GPIO implemention.
- Convert all users of the IXP4 custom GPIO
implementation to use gpiolib and delete the custom
implementation.
- Delete the custom Gemini GPIO implementation, also
completely unused.
- Various cleanups and renamings.
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Merge tag 'gpio-v3.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO changes from Linus Walleij:
"Here is the bulk of GPIO changes for the v3.13 development cycle.
I've got ACKs for the things that affect other subsystems (or it's my
own subsystem, like pinctrl). Most of that pertain to an attempt from
my side to consolidate and get rid of custom GPIO implementations in
the ARM tree. I will continue doing this.
The main change this time is the new GPIO descriptor API, background
for this can be found in Corbet's summary from this january in LWN:
http://lwn.net/Articles/533632/
Summary:
- Merged the GPIO descriptor API from Alexandre Courbot. This is a
first step toward trying to get rid of the global GPIO numberspace
for the future.
- Add an API so that driver can flag that a certain GPIO line is
being used by a irqchip backend for generating IRQs, so that we can
enforce checks, like not allowing users to switch that line to an
output at runtime, since this makes no sense. Implemented
corresponding calls in a few select drivers.
- ACPI GPIO cleanups, refactorings and switch to using the
descriptor-based interface.
- Support for the TPS80036 Palmas GPIO variant.
- A new driver for the Broadcom Kona GPIO SoC IP block.
- Device tree support for the PCF857x driver.
- A set of ARM GPIO refactorings with the goal of getting rid of a
bunch of custom GPIO implementations from the arch/arm/* tree:
* Move the IOP GPIO driver to the GPIO subsystem and fix all users
to use the gpiolib API for accessing GPIOs. Delete the old
custom GPIO implementation.
* Delete the unused custom PXA GPIO implemention.
* Convert all users of the IXP4 custom GPIO implementation to use
gpiolib and delete the custom implementation.
* Delete the custom Gemini GPIO implementation, also completely
unused.
- Various cleanups and renamings"
* tag 'gpio-v3.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (85 commits)
gpio: gpio-mxs: Remove unneeded dt checks
gpio: pl061: don't depend on CONFIG_ARM
gpio: bcm-kona: add missing .owner to struct gpio_chip
gpiolib: provide a declaration of seq_file in gpio/driver.h
gpiolib: include gpio/consumer.h in of_gpio.h for desc_to_gpio()
gpio: provide stubs for devres gpio functions
gpiolib: devres: add missing headers
gpiolib: make GPIO_DEVRES depend on GPIOLIB
gpiolib: devres: fix devm_gpiod_get_index()
gpiolib / ACPI: document the GPIO descriptor based interface
gpiolib / ACPI: allow passing GPIOF_ACTIVE_LOW for GpioInt resources
gpiolib / ACPI: add ACPI support for gpiod_get_index()
gpiolib / ACPI: convert to gpiod interfaces
gpiolib: add gpiod_get() and gpiod_put() functions
gpiolib: port of_ functions to use gpiod
gpiolib: export descriptor-based GPIO interface
Fixup "MAINTAINERS: GPIO-INTEL-MID: add maintainer"
gpio: bcm281xx: Don't print addresses of GPIO area in probe()
gpio: tegra: use new gpio_lock_as_irq() API
gpio: rcar: Include linux/of.h header
...
commit 6b3d8145dcfdbbb43f13544e16f44f4574f941dd
"gpiolib: make GPIO_DEVRES depend on GPIOLIB"
breaks builds when device drivers are using devm_gpio*
devres functions without enabling GPIOLIB, relying on
the devres code to be compiled anyway.
Provide stubs so that we get these if we're using the
devres functions without GPIOLIB.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This patch exports the gpiod_* family of API functions, a safer
alternative to the legacy GPIO interface. Differences between the gpiod
and legacy gpio APIs are:
- gpio works with integers, whereas gpiod operates on opaque handlers
which cannot be forged or used before proper acquisition
- gpiod get/set functions are aware of the active low state of a GPIO
- gpio consumers should now include <linux/gpio/consumer.h> to access
the new interface, whereas chips drivers will use
<linux/gpio/driver.h>
The legacy gpio API is now built as inline functions on top of gpiod.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This patch adds the infrastructure required to register non-linear gpio
ranges through gpiolib and the standard GPIO device tree bindings.
Signed-off-by: Christian Ruppert <christian.ruppert@abilis.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
It is currently often possible in many GPIO drivers to request
a GPIO line to be used as IRQ after calling gpio_to_irq() and,
as the gpiolib is not aware of this, set the same line to
output and start driving it, with undesired side effects.
As it is a bogus usage scenario to request a line flagged as
output to used as IRQ, we introduce APIs to let gpiolib track
the use of a line as IRQ, and also set this flag from the
userspace ABI.
The API is symmetric so that lines can also be flagged from
.irq_enable() and unflagged from IRQ by .irq_disable().
The debugfs file is altered so that we see if a line is
reserved for IRQ.
Cc: Enric Balletbo i Serra <eballetbo@gmail.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
GENERIC_GPIO is now equivalent to GPIOLIB and features that depended on
GENERIC_GPIO can now depend on GPIOLIB to allow removal of this option.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Some architectures (e.g. blackfin) provide gpio API without requiring
GPIOLIB support (ARCH_WANT_OPTIONAL_GPIOLIB). devm_gpio_* functions
should also work for these architectures, since they do not really
depend on GPIOLIB.
Add a new option GPIO_DEVRES (enabled by default) to control the build
of devres.c. It also removes the empty version of devm_gpio_*
functions for !GENERIC_GPIO build from linux/gpio.h, and moves the
function declarations from asm-generic/gpio.h into linux/gpio.h.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
To be crystal clear on what the arguments mean in this
funtion dealing with both GPIO and PIN ranges with confusing
naming, we now have gpio_offset and pin_offset and we are
on the clear that these are offsets into the specific GPIO
and pin controller respectively. The GPIO chip itself will
of course keep track of the base offset into the global
GPIO number space.
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Like with commit 3c739ad0df
it is not always enough to specify all the pins of a gpio_chip
from offset zero to be added to a pin map range, since the
mapping from GPIO to pin controller may not be linear at all,
but need to be broken into a few consecutive sub-ranges or
1-pin entries for complicated cases. The ranges may also be
sparse.
This alters the signature of the function to accept offsets
into both the GPIO-chip local pinspace and the pin controller
local pinspace.
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The <*/gpio.h> includes are updated again: now we need to account
for the problem introduced by commit:
595679a8038584df7b9398bf34f61db3c038bfea
"gpiolib: fix up function prototypes etc"
Actually we need static inlines in include/asm-generic/gpio.h
as well since we may have GPIOLIB but not PINCTRL.
Make sure to move all the CONFIG_PINCTRL business
to the end of the file so we are sure we have
declared struct gpio_chip.
And we need to keep the static inlines in <linux/gpio.h>
but here for the !CONFIG_GENERIC_GPIO case, and then we
may as well throw in a few warnings like the other
prototypes there, if someone would have the bad taste
of compiling without GENERIC_GPIO even.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The fact that of_gpiochip_add_pin_range() and
gpiochip_add_pin_range() share too much code is fragile and
will invariably mean that bugs need to be fixed in two places
instead of one.
So separate the concerns of gpiolib.c and gpiolib-of.c and
have the latter call the former as back-end. This is necessary
also when going forward with other device descriptions such
as ACPI.
This is done by:
- Adding a return code to gpiochip_add_pin_range() so we can
reliably check whether this succeeds.
- Get rid of the custom of_pinctrl_add_gpio_range() from
pinctrl. Instead create of_pinctrl_get() to just retrive the
pin controller per se from an OF node. This composite
function was just begging to be deleted, it was way to
purpose-specific.
- Use pinctrl_dev_get_name() to get the name of the retrieved
pin controller and use that to call back into the generic
gpiochip_add_pin_range().
Now the pin range is only allocated and tied to a pin
controller from the core implementation in gpiolib.c.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Commit 69e1601bca88809dc118abd1becb02c15a02ec71
"gpiolib: provide provision to register pin ranges"
Got most of it's function prototypes wrong, so fix this up by:
- Moving the void declarations into static inlines in
<linux/gpio.h> (previously the actual prototypes were declared
here...)
- Declare the gpiochip_add_pin_range() and
gpiochip_remove_pin_ranges() functions in <asm-generic/gpio.h>
together with the pin range struct declaration itself.
- Actually only implement these very functions in gpiolib.c
if CONFIG_PINCTRL is set.
- Additionally export the symbols since modules will need to
be able to do this.
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
pinctrl subsystem needs gpio chip base to prepare set of gpio
pin ranges, which a given pinctrl driver can handle. This is
important to handle pinctrl gpio request calls in order to
program a given pin properly for gpio operation.
As gpio base is allocated dynamically during gpiochip
registration, presently there exists no clean way to pass this
information to the pinctrl subsystem.
After few discussions from [1], it was concluded that may be
gpio controller reporting the pin range it supports, is a
better way than pinctrl subsystem directly registering it.
[1] http://comments.gmane.org/gmane.linux.ports.arm.kernel/184816
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
[Edited documentation a bit]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The bit 2 and 3 in GPIO flag are allocated for the
flag OPEN_DRAIN/OPEN_SOURCE. These bits are reused
for the flag EXPORT/EXPORT_CHANGEABLE and so creating
conflict.
Fix this conflict by assigning bit 4 and 5 for the
flag EXPORT/EXPORT_CHANGEABLE.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Allow drivers to use the modern request and configure idiom together
with devres.
As with plain gpio_request() and gpio_request_one() we can't implement
the old school version in terms of _one() as this would force the
explicit selection of a direction in gpio_request() which could break
systems if we pick the wrong one. Implementing devm_gpio_request_one()
in terms of devm_gpio_request() would needlessly complicate things or
lead to duplication from the unmanaged version depending on how it's
done.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Rather than requiring architectures that use gpiolib but don't have any
need to define anything custom to copy an asm/gpio.h provide a Kconfig
symbol which architectures must select in order to include gpio.h and
for other architectures just provide the trivial implementation directly.
This makes it much easier to do gpiolib updates and is also a step towards
making gpiolib APIs available on every architecture.
For architectures with existing boilerplate code leave a stub header in
place which warns on direct inclusion of asm/gpio.h and includes
linux/gpio.h to catch code that's doing this. Direct inclusion of
asm/gpio.h has long been deprecated.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jonas Bonn <jonas@southpole.se>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Currently the managed gpio_request() and gpio_free() are not stubbed out
for configurations not using gpiolib - do that to aid use in drivers.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Introduce new flags to automatically export GPIOs when using the convenience
functions gpio_request_one() or gpio_request_array(). This eases support for
custom boards where lots of GPIOs need to be exported for customer
applications.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Primarily gpio device driver changes with some minor side effects
under arch/arm and arch/x86. Also includes a few core changes such as
explicitly supporting (electrical) open source and open drain outputs
and some help for parsing gpio devicetree properties.
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Merge tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux-2.6
Pull GPIO changes for v3.4 from Grant Likely:
"Primarily gpio device driver changes with some minor side effects
under arch/arm and arch/x86. Also includes a few core changes such as
explicitly supporting (electrical) open source and open drain outputs
and some help for parsing gpio devicetree properties."
Fix up context conflict due to Laxman Dewangan adding sleep control for
the tps65910 driver separately for gpio's and regulators.
* tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux-2.6: (34 commits)
gpio/ep93xx: Remove unused inline function and useless pr_err message
gpio/sodaville: Mark broken due to core irqdomain migration
gpio/omap: fix redundant decoding of gpio offset
gpio/omap: fix incorrect update to context.irqenable1
gpio/omap: fix incorrect context restore logic in omap_gpio_runtime_*
gpio/omap: fix missing dataout context save in _set_gpio_dataout_reg
gpio/omap: fix _set_gpio_irqenable implementation
gpio/omap: fix trigger type to unsigned
gpio/omap: fix wakeup_en register update in _set_gpio_wakeup()
gpio: tegra: tegra_gpio_config shouldn't be __init
gpio/davinci: fix enabling unbanked GPIO IRQs
gpio/davinci: fix oops on unbanked gpio irq request
gpio/omap: Fix section warning for omap_mpuio_alloc_gc()
ARM: tegra: export tegra_gpio_{en,dis}able
gpio/gpio-stmpe: Fix the value returned by _get_value routine
Documentation/gpio.txt: Explain expected pinctrl interaction
GPIO: LPC32xx: Add output reading to GPO P3
GPIO: LPC32xx: Fix missing bit selection mask
gpio/omap: fix wakeups on level-triggered GPIOs
gpio/omap: Fix IRQ handling for SPARSE_IRQ
...
Adding support for the open source gpio on which client
can specify the open source property through GPIO flag
GPIOF_OPEN_SOURCE at the time of gpio request.
The open source pins are normally pulled low and it
cannot be driven to output with value of 0 and so
when client request for setting the pin to LOW, the
gpio will be set to input direction to make pin in tristate
and hence PULL-DOWN on pins will make the state to LOW.
The open source pin can be driven to HIGH by setting output
with value of 1.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Adding support for the open drain gpio on which client
can specify the open drain property through GPIO flag
GPIOF_OPEN_DRAIN at the time of gpio request.
The open drain pins are normally pulled high and it
cannot be driven to output with value of 1 and so
when client request for setting the pin to HIGH, the
gpio will be set to input direction to make pin in tristate
and hence PULL-UP on pins will make the state to HIGH.
The open drain pin can be driven to LOW by setting output
with value of 0.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
If a header file is making use of BUG, BUG_ON, BUILD_BUG_ON, or any
other BUG variant in a static inline (i.e. not in a #define) then
that header really should be including <linux/bug.h> and not just
expecting it to be implicitly present.
We can make this change risk-free, since if the files using these
headers didn't have exposure to linux/bug.h already, they would have
been causing compile failures/warnings.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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>
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_{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>
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>
This reverts commit 0fdae42d36, 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>
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>
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>
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>
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>
Commit 926b663ce8 (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>
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>
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>
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>
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>
