treewide: remove references to CREDITS ...

The CREDITS file was removed from barebox in 2015 by commit 6570288f2d97
("Remove the CREDITS file"). Remove references to it from several files.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

regulator: import Linux regulator_bulk API ...

Linux v5.6-rc1 contains 168 references to regultor_bulk_get, which
allows getting multiple regulators to set at once. Instead of open
coding them when porting code, port over the helpers to barebox.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

regulator: add function to get regulator by its name ...

Useful for getting regulators that are not correctly associated with a
device.

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

regulator: Assume probe deferral instead of missing regulator ...

Don't report requested regulator (via of_regulator_get()) as
non-existent if said regulator is missing from regulator list. Instead
report it as probe deferral to give other, unprobed, drivers a chance
to resolve this.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

regulator: Add support for setting regulator's voltage ...

Add code needed to implement regulator_set_voltage(). Currently only
bare minmum needed for ANATOP driver (added in follow up commit) is
supported.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

regulator: Convert drivers to use struct regulator_desc ...

To simplify porting kernel code, port a very basic struct
regulator_desc and convert all of the code to use it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

string: Fix (v)asprintf prototypes ...

Our asprintf and vasprintf have different prototypes than the glibc
functions. This causes trouble when we want to share barebox code
with userspace code. Change the prototypes for (v)asprintf to match
the glibc prototypes. Since the current (v)asprintf are convenient
to use change the existing functions to b(v)asprintf.

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

regulator: Add support for regulator-boot-on device tree property ...

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

regulator: Factor out functions to work with regulator_internal ...

Internally we only have a struct regulator_internal, so factor
out regulator_enable_internal and regulator_disable_internal
functions which can be called from regulator internal code.

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

regulator: allow to use it with non DT device ...

this will use the device name as regulator name

with the same Algo as clkdev for lookup

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Add initial regulator support ...

Provide minimal regulator support. Only supported operations are enabling
and disabling regulators. Association of devices with their regulators is
limited to devicetree only. If regulator support is disabled the API expands
to static inline stubs so consumers can still use the API.

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