Hi,
On Mon, Apr 28, 2014 at 10:35 PM, Inderpal Singh <inderpal.s@xxxxxxxxxxx> wrote:
> On some SoCs there could be requirements that two or more voltage
> regulators need to maintain certain skew for proper functioning.
>
> This patch implements a new vitual locker type regulator which can
> have multiple output and input regulators. The real regulators will
> be hidden under the virtual output regulators. The consumer of the
> real regulators need not change anything. Only the name of the real
> regulators need to be changed.
>
> This patch has been tested on exynos5420 based smdk5420.
>
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
> Signed-off-by: Inderpal Singh <inderpal.s@xxxxxxxxxxx>
> ---
> .../bindings/regulator/locker-regulator.txt | 36 ++
> drivers/regulator/Kconfig | 9 +
> drivers/regulator/Makefile | 1 +
> drivers/regulator/locker.c | 472 +++++++++++++++++++++
> include/linux/regulator/locker.h | 35 ++
> 5 files changed, 553 insertions(+)
I cornered Rob and Mark Rutland a little bit about this at ELC today
(sorry!). Neither of them was a huge ran of adding a pseudo device.
Rob suggested that Mark Brown might be the best person to give
direction here. Mark Brown: any thoughts?
Potentially we could also make this type of thing a core regulator property:
buck2_reg: BUCK2 {
regulator-name = "vdd_arm";
regulator-min-microvolt = <800000>;
regulator-max-microvolt = <1500000>;
regulator-always-on;
regulator-boot-on;
regulator-op-mode = <1>;
regulator-ramp-delay = <12500>;
};
buck3_reg: BUCK3 {
regulator-name = "vdd_int";
regulator-min-microvolt = <800000>;
regulator-max-microvolt = <1400000>;
regulator-always-on;
regulator-boot-on;
regulator-op-mode = <1>;
regulator-ramp-delay = <12500>;
regulator-lock-to = <&buck2>;
regulator-lock-within = <300000>;
};
Another option is to add no device tree code at all and add code to
the devfreq / cpufreq drivers used on this device. In order to do
this cleanly I think we'd need to extend the regulator core's
notification scheme to introduce a new event:
REGULATOR_EVENT_VOLTAGE_CHANGING that's called _before_ a voltage
change happened.
Or maybe there's some yet different (cleaner) solution that I haven't
thought of.
-Doug
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