OF: gpio: don't warn if ignored GPIO flag matches the behavior ...

Port of the upstream accepted change to the Linux kernel.

Some devicetrees specify the ACTIVE_LOW flag in the fixed regulator GPIO
handle. While this has always been ignored, it's consistent with the
behavior of the regulator binding in the absence of the
"enable-active-high" DT property. It doesn't make much sense to print a
user visible warning for a configuration which is consistent, so only
print the warning if the GPIO flag contradicts the behavior dictated by
by the enable-active-high property.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

OF: gpio: Add special quirk to parse regulator flags ...

To make fec work with devicetree on imx28-evk, partially port following
kernel patch:

|commit a603a2b
|Author: Linus Walleij <linus.walleij@linaro.org>
|Date:   Sat Dec 30 16:26:36 2017 +0100
|
|    gpio: of: Add special quirk to parse regulator flags
|
|    While most GPIOs are indicated to be active low or open drain using
|    their twocell flags, we have legacy regulator bindings to take into
|    account.
|
|    Add a quirk respecting the special boolean active-high and open
|    drain flags when parsing regulator nodes for GPIOs.
|
|    This makes it possible to get rid of duplicated inversion semantics
|    handling in the regulator core and any regulator drivers parsing
|    and handling this separately.
|
|    Unfortunately the old regulator inversion semantics are specified
|    such that the presence or absence of "enable-active-high" solely
|    controls the semantics, so we cannot deprecate this in favor
|    of the phandle-provided inversion flag, instead any such phandle
|    inversion flag provided in the second cell of a GPIO handle must be
|    actively ignored, so we print a warning to contain the situation
|    and make things easy for the users.
|
|    Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

OF: gpio: Silence error message on -EPROBE_DEFER ...

With deferred probing, -EPROBE_DEFER is not worth spilling an error.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

of_gpio: return error if no device found ...

of_get_named_gpio_flags used to return 'ret' when no device
is found, but 'ret' is zero here. Return an error instead.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

gpio: reduce noise when parsing DT ...

Some GPIOs are optional, so it might not be an error if we can not find
a DT property. Do the same thing as the Linux kernel and only print a
debug message not an error.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

OF: gpio: convert DT based gpio handling to new OF API ...

This creates a Linux OF API compatible counterpart of of_get_named_gpio_flags.
Existing of_get_named_gpio is converted to a static inline function, which is
in the corresponding of_gpio.h include. While at it, drivers/of/gpio.c is
also renamed to drivers/of/of_gpio.c to follow the of_ prefix naming scheme.
The new include is also added to existing users of of_get_named_gpio.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>