soc: samsung: exynos-pmu: Add regmap support for SoCs that protect PMU regs

Some Exynos based SoCs like Tensor gs101 protect the PMU registers for
security hardening reasons so that they are only write accessible in el3
via an SMC call.

As most Exynos drivers that need to write PMU registers currently obtain a
regmap via syscon (phys, pinctrl, watchdog). Support for the above usecase
is implemented in this driver using a custom regmap similar to syscon to
handle the SMC call. Platforms that don't secure PMU registers, get a mmio
regmap like before. As regmaps abstract out the underlying register access
changes to the leaf drivers are minimal.

A new API exynos_get_pmu_regmap_by_phandle() is provided for leaf drivers
that currently use syscon_regmap_lookup_by_phandle(). This also handles
deferred probing.

Tested-by: Sam Protsenko <semen.protsenko@linaro.org>
Tested-by: Alexey Klimov <alexey.klimov@linaro.org>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Link: https://lore.kernel.org/r/20240220220613.797068-2-peter.griffin@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

soc: samsung: exynos-pmu: Re-introduce Exynos4212 support

Support for the Exynos4212 SoC was originally dropped as there were
no boards using it. We will be adding a device that uses it, so add
it back.

This reverts commit c40610198f35e8264f9175dafe74db6288a07eda.

Signed-off-by: Artur Weber <aweber.kernel@gmail.com>
Link: https://lore.kernel.org/r/20230501195525.6268-5-aweber.kernel@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

soc: samsung: Rename Samsung and Exynos to lowercase

Fix up inconsistent usage of upper and lowercase letters in "Samsung"
and "Exynos" names.

"SAMSUNG" and "EXYNOS" are not abbreviations but regular trademarked
names. Therefore they should be written with lowercase letters starting
with capital letter.

The lowercase "Exynos" name is promoted by its manufacturer Samsung
Electronics Co., Ltd., in advertisement materials and on website.

Although advertisement materials usually use uppercase "SAMSUNG", the
lowercase version is used in all legal aspects (e.g. on Wikipedia and in
privacy/legal statements on
https://www.samsung.com/semiconductor/privacy-global/).

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

soc: samsung: Add SPDX license identifiers

Replace GPL license statements with SPDX GPL-2.0 license identifiers.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

soc: samsung: Remove Exynos4212 related dead code

Support for Exynos4212 SoCs has been removed by commit bca9085e0ae9 ("ARM:
dts: exynos: remove Exynos4212 support (dead code)"), so there is no need
to keep remaining dead code related to this SoC version.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

soc: samsung: Do not build ARMv7 PMU drivers on ARMv8

The Exynos Power Management Unit (PMU) drivers contain quite large
static arrays of register values necessary for given Exynos SoC to enter
low power mode. All this data is useless for ARMv8 SoC like
Exynos5433, because the image will not be shared between ARMv7 and
ARMv8.

Add additional Kconfig symbol for selecting the SoC-specific driver
addons thus skipping the useless data in the final image (this is
similar approach to chosen for Exynos clock controller drivers):
- exynos-pmu driver will be compiled on both architectures ARMv7
and ARMv8,
- additional driver_data for ARMv7 SoCs will not be built on ARMv8
and a macro will return NULL for them in of_device_id - this should
be safe as these compatibles cannot match on ARMv7 and driver
anyway handles NULL driver_data,
- on ARMv8 compile only exynos-pmu driver which exposes the
syscon-regmap for PMU address space.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>

drivers: soc: Add support for Exynos PMU driver

This patch moves Exynos PMU driver implementation from "arm/mach-exynos"
to "drivers/soc/samsung". This driver is mainly used for setting misc
bits of register from PMU IP of Exynos SoC which will be required to
configure before Suspend/Resume. Currently all these settings are done
in "arch/arm/mach-exynos/pmu.c" but moving ahead for ARM64 based SoC
support, there is a need of this PMU driver in driver/* folder.

This driver uses existing DT binding information and there should
be no functionality change in the supported platforms.

Signed-off-by: Amit Daniel Kachhap <amitdanielk@gmail.com>
[tested on Peach-Pi (Exynos5880)]
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
[for testing on Trats2 (Exynos4412) and Odroid XU3 (Exynos5422)]
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
[k.kozlowski: Rebased, add necessary infrastructure for building and
selecting drivers/soc because original patchset was on top of movement
SROMc to drivers/soc]
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>