soc: samsung: exynos-chipid: convert to driver and merge exynos-asv
The Exynos Chip ID driver on Exynos SoCs has so far only informational
purpose - to expose the SoC device in sysfs. No other drivers depend on
it so there is really no benefit of initializing it early.
The code would be the most flexible if converted to a regular driver.
However there is already another driver - Exynos ASV (Adaptive Supply
Voltage) - which binds to the device node of Chip ID.
The solution is to convert the Exynos Chip ID to a built in driver and
merge the Exynos ASV into it.
This has several benefits:
1. Although the Exynos ASV driver binds to a device node present in all
Exynos DTS (generic compatible), it fails to probe except on the
supported ones (only Exynos5422). This means that the regular boot
process has a planned/normal device probe failure.
Merging the ASV into Chip ID will remove this probe failure because
the final driver will always bind, just with disabled ASV features.
2. Allows to use dev_info() as the SoC bus is present (since
core_initcall).
3. Could speed things up because of execution of Chip ID code in a SMP
environment (after bringing up secondary CPUs, unlike early_initcall),
This reduces the amount of work to be done early, when the kernel has
to bring up critical devices.
5. Makes the Chip ID code defer-probe friendly,
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20201207190517.262051-5-krzk@kernel.org
Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>
diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
index fc7f48a..5745d7e 100644
--- a/drivers/soc/samsung/Kconfig
+++ b/drivers/soc/samsung/Kconfig
@@ -7,21 +7,19 @@
if SOC_SAMSUNG
-config EXYNOS_ASV
- bool "Exynos Adaptive Supply Voltage support" if COMPILE_TEST
- depends on (ARCH_EXYNOS && EXYNOS_CHIPID) || COMPILE_TEST
- select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
-
# There is no need to enable these drivers for ARMv8
config EXYNOS_ASV_ARM
bool "Exynos ASV ARMv7-specific driver extensions" if COMPILE_TEST
- depends on EXYNOS_ASV
+ depends on EXYNOS_CHIPID
config EXYNOS_CHIPID
- bool "Exynos Chipid controller driver" if COMPILE_TEST
+ bool "Exynos ChipID controller and ASV driver" if COMPILE_TEST
depends on ARCH_EXYNOS || COMPILE_TEST
+ select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
select MFD_SYSCON
select SOC_BUS
+ help
+ Support for Samsung Exynos SoC ChipID and Adaptive Supply Voltage.
config EXYNOS_PMU
bool "Exynos PMU controller driver" if COMPILE_TEST