gpio: regmap: move drvdata to config data

Drop gpio_regmap_set_drvdata() and instead add it to the configuration
data passed to gpio_regmap_register().

gpio_regmap_set_drvdata() can't really be used in a race free way. This
is because the gpio_regmap object which is needed by _set_drvdata() is
returned by gpio_regmap_register(). On the other hand, the callbacks
which use the drvdata might already be called right after the
gpiochip_add() call in gpio_regmap_register(). Therefore, we have to
provide the drvdata early before we call gpiochip_add().

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

gpio: regmap: set gpio_chip of_node

This is needed for properly registering GPIO regmap as a child of a regmap
pin controller.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20210324081923.20379-3-noltari@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

gpio: regmap: fix type clash

GPIO_REGMAP_ADDR_ZERO() cast to unsigned long but the actual config
parameters are unsigned int. We use unsigned int here because that is
the type which is used by the underlying regmap.

Fixes: ebe363197e52 ("gpio: add a reusable generic gpio_chip using regmap")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200725232337.27581-1-michael@walle.cc
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

gpio: add a reusable generic gpio_chip using regmap

There are quite a lot simple GPIO controller which are using regmap to
access the hardware. This driver tries to be a base to unify existing
code into one place. This won't cover everything but it should be a good
starting point.

It does not implement its own irq_chip because there is already a
generic one for regmap based devices. Instead, the irq_chip will be
instantiated in the parent driver and its irq domain will be associate
to this driver.

For now it consists of the usual registers, like set (and an optional
clear) data register, an input register and direction registers.
Out-of-the-box, it supports consecutive register mappings and mappings
where the registers have gaps between them with a linear mapping between
GPIO offset and bit position. For weirder mappings the user can register
its own .xlate().

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200528145845.31436-3-michael@walle.cc
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>