Commit 9e4555d1e54a ("gpiolib: add support for scope-based management to
gpio_device") sought to add scope-based gpio_device refcounting, but
erroneously forgot a negation of IS_ERR_OR_NULL().

As a result, gpio_device_put() is not called if the gpio_device pointer
is valid (meaning the ref is leaked), but only called if the pointer is
NULL or an ERR_PTR().

While at it drop a superfluous trailing semicolon.

Fixes: 9e4555d1e54a ("gpiolib: add support for scope-based management to gpio_device")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Remove second `#include <linux/err.h>`. Remove `#include <asm/errno.h>`
too as it's included by `err.h`.

Signed-off-by: Wang Jinchao <wangjinchao@xfusion.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

gpio: remove gpiochip_is_requested()

- provide a safer alternative to gpiochip_is_requested()
- convert all existing users
- remove gpiochip_is_requested()

We have no external users of gpiochip_is_requested(). Let's remove it
and replace its internal calls with direct testing of the REQUESTED flag.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

Rework for_each_requested_gpio_in_range() to use the new helper to
retrieve a dynamically allocated copy of the descriptor label and free
it at the end of each iteration. We need to leverage the CLASS()'
destructor to make sure that the label is freed even when breaking out
of the loop.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

gpiochip_is_requested() not only has a misleading name but it returns
a pointer to a string that is freed when the descriptor is released.

Provide a new helper meant to replace it, which returns a copy of the
label string instead.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

Provide a getter for the GPIO device label string so that users don't
have to dereference struct gpio_chip directly.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

With all users of gpiochip_find() converted to using gpio_device_find(),
we can now remove this function from the kernel.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Let's start adding getters for the opaque struct gpio_device. Start with
a function allowing to retrieve the base GPIO number.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

Accessing struct gpio_chip backing a GPIO device is only allowed for the
actual providers of that chip.

Similarly to how we introduced gpio_device_find() in order to replace
the abused gpiochip_find(), let's introduce a counterpart to
gpiod_to_chip() that returns a reference to the GPIO device owning the
descriptor. This is done in order to later remove gpiod_to_chip()
entirely.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Peter Rosin <peda@axentia.se>
Acked-by: Linus Walleij <linus.walleij@linaro.org>