The S3C2416/S3C2450 SoCs support two sources for the armclk.

The first source is the so called armdiv which divides the msysclk down
to provide necessary cpu rates. In this mode the core voltage must be
always at 1.3V. The frequency from the armdiv is not allowed to be
lower than the hclk frequency.

In the second mode the armclk can be sourced directly from the hclk in
the so called "dynamic voltags scaling" (dvs) mode. Here the armdiv
isn't used at all. Also in this mode the core voltage may be lowered.
Existing hardware and tests with it suggest 1.0V as sufficient.

When changing the clock source to the armdiv from the hclk, the SoC
shows stability issues if the new frequency is higher than the current
hclk frequency. Hence the driver always forces the armdiv to the hclk
frequency before the source change and lets the cpufreq issue another
set_target call for higher frequencies.

To mark the hclk frequency as lower as the corresponding armdiv
frequency it is set 1MHz below the real frequency. This lets the cpufreq
framework change between 133MHz based on hclk and 133MHz based on armdiv
at will.
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
Tested-by: NAndrey Gusakov <dron0gus@gmail.com>
Signed-off-by: NDave Jones <davej@redhat.com>

exynos4210-cpufreq.c is not buildable on non-exynos builds, so it's
pointless allowing this option to be exposed.  Fix this by adding a
dependency on ARCH_EXYNOS.

drivers/cpufreq/exynos4210-cpufreq.c:20:29: error: mach/regs-clock.h: No such file or directory
drivers/cpufreq/exynos4210-cpufreq.c:21:26: error: mach/cpufreq.h: No such file or directory
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Cc: cpufreq@vger.kernel.org
Cc: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NDave Jones <davej@redhat.com>

To support various EXYNOS series SoCs commonly,
added exynos common structure.
exynos-cpufreq.c => EXYNOS series common cpufreq driver
exynos4210-cpufreq.c => EXYNOS4210 support cpufreq driver
Signed-off-by: NJaecheol Lee <jc.lee@samsung.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NDave Jones <davej@redhat.com>

Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NDave Jones <davej@redhat.com>

According to discussion of the ARM arch subsystem migration,
ARM cpufreq drivers move to drivers/cpufreq. So this patch
adds Kconfig.arm for ARM like x86 and adds Samsung S5PV210
and EXYNOS4210 cpufreq driver compile in there.
As a note, otherw will be moved.

Cc: Dave Jones <davej@redhat.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NDave Jones <davej@redhat.com>