The conversion of all GPIO drivers to using the .set_rv() and
.set_multiple_rv() callbacks from struct gpio_chip (which - unlike their
predecessors - return an integer and allow the controller drivers to
indicate failures to users) is now complete and the legacy ones have
been removed. Rename the new callbacks back to their original names in
one sweeping change.

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

struct gpio_chip now has callbacks for setting line values that return
an integer, allowing to indicate failures. Convert the driver to using
them.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Link: https://lore.kernel.org/r/20250407-gpiochip-set-rv-gpio-part1-v1-4-78399683ca38@linaro.org
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

Setting GPIO direction = high, sometimes results in GPIO value = 0.

If a GPIO is pulled high, the following construction results in the
value being 0 when the desired value is 1:

$ echo "high" > /sys/class/gpio/gpio336/direction
$ cat /sys/class/gpio/gpio336/value
0

Before the GPIO direction is changed from an input to an output,
exar_set_value() is called with value = 1, but since the GPIO is an
input when exar_set_value() is called, _regmap_update_bits() reads a 1
due to an external pull-up.  regmap_set_bits() sets force_write =
false, so the value (1) is not written.  When the direction is then
changed, the GPIO becomes an output with the value of 0 (the hardware
default).

regmap_write_bits() sets force_write = true, so the value is always
written by exar_set_value() and an external pull-up doesn't affect the
outcome of setting direction = high.

The same can happen when a GPIO is pulled low, but the scenario is a
little more complicated.

$ echo high > /sys/class/gpio/gpio351/direction
$ cat /sys/class/gpio/gpio351/value
1

$ echo in > /sys/class/gpio/gpio351/direction
$ cat /sys/class/gpio/gpio351/value
0

$ echo low > /sys/class/gpio/gpio351/direction
$ cat /sys/class/gpio/gpio351/value
1

Fixes: 36fb7218e878 ("gpio: exar: switch to using regmap")
Co-developed-by: Matthew McClain <mmcclain@noprivs.com>
Signed-off-by: Matthew McClain <mmcclain@noprivs.com>
Signed-off-by: Sai Kumar Cholleti <skmr537@gmail.com>
Cc: stable@vger.kernel.org
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20241105071523.2372032-1-skmr537@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The platform_set_drvdata() was needed when the driver had an explicit
remove function.
That function got removed a while back, so we don't need to keep a pointer
(on 'dev->driver_data') for the private data of the driver anymore.

Reviewed-by: Alexandru Ardelean <alex@shruggie.ro>
Signed-off-by: Andrei Coardos <aboutphysycs@gmail.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

It's possible that PCI device can provide an IO port resource for
the device. regmap MMIO currently uses MMIO by default. With an
additional flag we enable support for IO port accesses.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: William Breathitt Gray <william.gray@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

When EXAR xr17v35x chips are cascaded in order to access the MPIO registers
(part of the Device Configuration Registers) of the secondary chips, an offset
needs to be applied based on the number of primary chip's UART channels.

Signed-off-by: Qingtao Cao <qingtao.cao@digi.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

We can simplify the error path in probe() and drop remove() entirely if
we provide a devm action for freeing the device ID.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

We can simplify the code in gpio-exar by using regmap. This allows us to
drop the mutex (regmap provides its own locking) and we can also reuse
regmap's bit operations instead of implementing our own update function.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Provide and use helpers for calculating the register address and bit
offset instead of hand coding it in every function.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

It's more elegant to use a helper local variable to store the address
of the underlying struct device than to dereference pdev everywhere. It
also has the benefit of avoiding unnecessary line breaks.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>