User space can currently both read and set values of input lines using
the character device. This was not allowed by the old sysfs interface
nor is it a correct behavior.

Check the first descriptor in the set for the OUT flag when asked to
set values and return -EPERM if the line is input.
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Allow gpiolib to read back the current I/O direction configuration by
implementing the .get_direction() callback.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

One line in gpiolib_dbg_show() still fits 80 characters, so,
join it to be like that in order to increase readability.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

platform_get_resource() may fail and return NULL, so we should
better check it's return value to avoid a NULL pointer dereference
a bit later in the code.

This is detected by Coccinelle semantic patch.

@@
expression pdev, res, n, t, e, e1, e2;
@@

res = platform_get_resource(pdev, t, n);
+ if (!res)
+   return -EINVAL;
... when != res == NULL
e = devm_ioremap(e1, res->start, e2);
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Compile-testing the driver fails unless OF_GPIO is enabled:

drivers/gpio/gpio-mt7621.c: In function 'mediatek_gpio_bank_probe':
drivers/gpio/gpio-mt7621.c:228:10: error: 'struct gpio_chip' has no member named 'of_node'

Fixes: 4ba9c3af ("gpio: mt7621: Add a driver for MT7621")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

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: Arnd Bergmann <arnd@arndb.de>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus 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: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus 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: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus 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: Rafael David Tinoco <rafael.tinoco@linaro.org>
Signed-off-by: Linus 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: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Linus 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: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus 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: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Linus 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: Linus Walleij <linus.walleij@linaro.org>

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

Add a devicetree binding documentation for the mt7621 gpio.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: NeilBrown <neil@brown.name>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus 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: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus 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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus 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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus 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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus 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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus 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: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

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

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

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: Linus 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: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Linus 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: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

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

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

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: Linus 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: Linus 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: Linus 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: Linus 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: Linus 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: Linus 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: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus 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: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

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

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

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

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