Gcc cannot always see that BUG_ON(1) is guaranteed to not
return, so we get a warning message in some configurations:

drivers/gpio/gpio-aspeed.c: In function 'bank_reg':
drivers/gpio/gpio-aspeed.c:244:1: error: control reaches end of non-void function [-Werror=return-type]

Using a plain BUG() is easier here and avoids the problem.

Fixes: 44ddf559 ("gpio: aspeed: Rework register type accessors")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Two out of three calls to ->get_direction (excluding, of course,
gpiod_get_direction() itself) are using gpiod_get_direction() and
one is still open coded.

Replace the latter one to use same API for sake of consistency.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Since we put static variable to a header file it's copied to each module
that includes the header. But not all of them are actually used it.

Mark gpio_suffixes array with __maybe_unused to hide a compiler warning:

In file included from
drivers/gpio/gpiolib-legacy.c:6:0:
drivers/gpio/gpiolib.h:95:27: warning: ‘gpio_suffixes’ defined but not used [-Wunused-const-variable=]
 static const char * const gpio_suffixes[] = { "gpios", "gpio" };
                           ^~~~~~~~~~~~~
In file included from drivers/gpio/gpiolib-devprop.c:17:0:
drivers/gpio/gpiolib.h:95:27: warning: ‘gpio_suffixes’ defined but not used [-Wunused-const-variable=]
 static const char * const gpio_suffixes[] = { "gpios", "gpio" };
                           ^~~~~~~~~~~~~
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Following logic from commit: 22f6592b, GPIOHANDLE_REQUEST_OUTPUT
should handle errors same way as GPIOHANDLE_REQUEST_INPUT does, or else
the following error occurs:

gpio-mockup-chardev: gpio<gpiochip1> line<0> test flag<0x2> value<0>: No
such file or directory

despite the real result of gpio_pin_test(), gpio_debugfs_get() and
gpiotools_request_linehandle() functions.
Signed-off-by: NRafael David Tinoco <rafael.tinoco@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Avoid replication of error code conversion in non-DT GPIO consumers'
code by returning -EPROBE_DEFER from gpiod_find() in case a chip
identified by its label in a registered lookup table is not ready.

See https://lkml.org/lkml/2018/5/30/176 for example case.
Suggested-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: NJanusz Krzysztofik <jmkrzyszt@gmail.com>
Reviewed-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

In case we try to lock GPIO pin as IRQ when something going wrong
we print a misleading message.

Correct this by checking an error code from ->get_direction() in
gpiochip_lock_as_irq() and printing a corresponding message.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Some i.MX SoCs have GPIO clock gate in CCM, accessing
GPIO registers needs to enable GPIO clock gate first,
i.MX GPIO driver will enable clock gate if there is
clock property in GPIO node of dtb, add optional property
to i.MX GPIO binding doc.
Signed-off-by: NAnson Huang <Anson.Huang@nxp.com>
Reviewed-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This fixes some syntactic nits that makes the GPIO maintainer
happier. It is way easier to show by example and do it myself
than to try to explain it with comments. It's just my personal
taste of minimalism.

Cc: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Cc: NeilBrown <neil@brown.name>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add driver support for gpio of MT7621 SoC.
Signed-off-by: NSergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: NNeilBrown <neil@brown.name>
[Switched wording WIDTH to STRIDE]
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add a devicetree binding documentation for the mt7621 gpio.
Signed-off-by: NSergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: NNeilBrown <neil@brown.name>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

For easy grepping on debug purposes join string literals back in the
messages.

While here, fix couple of small indentation issues.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

On the Aspeed chip, the GPIOs can be under control of the ARM
chip or of the ColdFire coprocessor. (There's a third command
source, the LPC bus, which we don't use or support yet).

The control of which master is allowed to modify a given
GPIO is per-bank (8 GPIOs).

Unfortunately, systems already exist for which we want to
use GPIOs of both sources in the same bank.

This provides an API exported by the gpio-aspeed driver
that an aspeed coprocessor driver can use to "grab" some
GPIOs for use by the coprocessor, and allow the coprocessor
driver to provide callbacks for arbitrating access.

Once at least one GPIO of a given bank has been "grabbed"
by the coprocessor, the entire bank is marked as being
under coprocessor control. It's command source is switched
to the coprocessor.

If the ARM then tries to write to a GPIO in such a marked bank,
the provided callbacks are used to request access from the
coprocessor driver, which is responsible to doing whatever
is necessary to "pause" the coprocessor or prevent it from
trying to use the GPIOs while the ARM is doing its accesses.

During that time, the command source for the bank is temporarily
switched back to the ARM.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: NJoel Stanley <joel@jms.id.au>
Reviewed-by: NAndrew Jeffery <andrew@aj.id.au>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This adds the definitions for the command source registers
and a helper to set them.

Those registers allow to control which bus master on the
SoC is allowed to modify a given bank of GPIOs and will
be used by subsequent patches.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: NJoel Stanley <joel@jms.id.au>
Reviewed-by: NAndrew Jeffery <andrew@aj.id.au>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The Aspeed GPIO hardware has a quirk: the value register, for an
output GPIO, doesn't contain the last value written (the write
latch content) but the sampled input value.

This means that when reading back shortly after writing, you can
get an incorrect value as the input value is delayed by a few
synchronizers.

The HW supports a separate read-only register "Data Read Register"
which allows you to read the write latch instead.

This adds the definition for it, and uses it for the initial
population of the GPIO value cache. It will be used more in
subsequent patches.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: NJoel Stanley <joel@jms.id.au>
Reviewed-by: NAndrew Jeffery <andrew@aj.id.au>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Use a single accessor function for all register types instead
of several spread around. This will make it easier/cleaner
to introduce new registers and keep the mechanism in one
place.

The big switch/case is optimized at compile time since the
switch value is a constant.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: NJoel Stanley <joel@jms.id.au>
Reviewed-by: NAndrew Jeffery <andrew@aj.id.au>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Don't warn about missing interrupts support when the parent interrupt is
not defined. Enabling interrupts support would not make it work anyway.
Signed-off-by: NBaruch Siach <baruch@tkos.co.il>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

I don't like the __namespace and this is simple enough to just
inline at all sites.

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Acked-by: NAlessandro Rubini <rubini@gnudd.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This removes the custom implementation of the BIT() macro
and inlines all calls to the helper.

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Acked-by: NAlessandro Rubini <rubini@gnudd.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Acked-by: NAlessandro Rubini <rubini@gnudd.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This purely syntactic change switches unsigned char to
u8 in the driver.

Cc: Bruno Randolf <br1@einfach.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The chip has a bit for controlling open drain, and it is
easy to implement the callback to support open drain when
needed, so let's implement it.

Cc: Bruno Randolf <br1@einfach.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Bit 0 in the config register obviously controls the direction
of the GPIO so instead of hammering 0x0/0x1 into that register,
use read-modify-write so that we can also alter the other bits
in the register.

Cc: Bruno Randolf <br1@einfach.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

It's pretty simple to implement the .get_direction() for this
chip, so let's just do it.

Cc: Bruno Randolf <br1@einfach.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.

Cc: Bruno Randolf <br1@einfach.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

It's pretty simple to implement the .get_direction() for this
chip, so let's just do it.

Cc: Denis Turischev <denis.turischev@compulab.co.il>
Cc: Daniel Krueger <daniel.krueger@systec-electronic.com>
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.

Cc: Denis Turischev <denis.turischev@compulab.co.il>
Cc: Daniel Krueger <daniel.krueger@systec-electronic.com>
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add an implementation to get the current GPIO state.

The callback is used by the leds-gpio driver for example, in case the
current LED/GPIO state should be kept during driver load.
Signed-off-by: NMathias Kresin <dev@kresin.me>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add support for the Tegra194 GPIO bank configuration.
Signed-off-by: NMikko Perttunen <mperttunen@nvidia.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The Tegra194 GPIO controller is similar to the one in Tegra186.
Add relevant information to the device tree binding documentation.
Signed-off-by: NMikko Perttunen <mperttunen@nvidia.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The GPIO subsystem provides dummy GPIO consumer functions if GPIOLIB is
not enabled. Hence drivers that depend on GPIOLIB, but use GPIO consumer
functionality only, can still be compiled if GPIOLIB is not enabled.

Relax the dependency on GPIOLIB if COMPILE_TEST is enabled, where
appropriate.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NEvgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The GPIO (descriptor) API registers a "label" naming what is
currently using the GPIO line. Typically this is taken from
things like the device tree node, so "reset-gpios" will result
in he line being labeled "reset".

The technical effect is pretty much zero: the use is for
debug and introspection, such as "lsgpio" and debugfs files.

However sometimes the user want this cuddly feeling of
listing all GPIO lines and seeing exactly what they are for
and it gives a very fulfilling sense of control. Especially
in the cases when the device tree node doesn't provide a
good name, or anonymous GPIO lines assigned just to
"gpios" in the device tree because the usage is implicit.

For these cases it may be nice to be able to label the
line directly and explicitly.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>