reset: berlin: support module build

Make reset-berlin driver to be tristate module, support to build as
a module, this is useful for GKI.

Partially reverts commit ed4dba99cae8 ("reset: berlin: make it
explicitly non-modular")

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Link: https://lore.kernel.org/r/20210607181015.5b8d3711@xhacker.debian
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

reset: berlin: replace unsigned with unsigned int

Fixes a checkpatch warning:

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
#55: FILE: drivers/reset/reset-berlin.c:55:
+ unsigned offset, bit;

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

reset: berlin: make it explicitly non-modular

The Kconfig currently controlling compilation of this code is:

drivers/reset/Kconfig:config RESET_BERLIN
drivers/reset/Kconfig: bool "Berlin Reset Driver" if COMPILE_TEST
drivers/reset/Kconfig: default ARCH_BERLIN

or

arch/arm/mach-berlin/Kconfig:menuconfig ARCH_BERLIN
arch/arm/mach-berlin/Kconfig: bool "Marvell Berlin SoCs" if ARCH_MULTI_V7

or

arch/arm64/Kconfig.platforms:config ARCH_BERLIN
arch/arm64/Kconfig.platforms: bool "Marvell Berlin SoC Family"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

Since module_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Antoine Tenart <antoine.tenart@free-electrons.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

reset: berlin: Make reset_control_ops const

The berlin_reset_ops structure is never modified. Make it const.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Antoine Tenart <antoine.tenart@free-electrons.com>

reset: berlin: drop DT cell size check

Now that the DT cell size check has been moved to the core,
there is no need to check again.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

reset: check return value of reset_controller_register()

Currently, reset_controller_register() always return 0, but it would
be better to check its return code.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

reset: berlin: drop arch_initcall initialization

With proper platform driver probing for berlin reset driver, drop the
arch_initcall workaround.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

reset: berlin: convert to a platform driver

The Berlin reset controller was introduced without being a platform
driver because of a needed DT rework: the node describing the reset
controller also describes the pinctrl and clk controllers...

Prepare conversion by adding a platform driver probe to a new
compatible "marvell,berlin2-reset" with syscon regmap.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

reset: add the Berlin reset controller driver

Add a reset controller for Marvell Berlin SoCs which is used by the
USB PHYs drivers (for now).

Signed-off-by: Antoine Ténart <antoine.tenart@free-electrons.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>