[PATCH 2/2] ARM: mvebu: use regulator-boot-on on Armada 388 GP
Gregory CLEMENT
gregory.clement at free-electrons.com
Tue Dec 22 04:23:20 PST 2015
Hi Thomas,
On lun., déc. 21 2015, Thomas Petazzoni <thomas.petazzoni at free-electrons.com> wrote:
> Really, what we meant by regulator-always-on is that the regulators
> are already turned on by the bootloader, for which regulator-boot-on
> is a better description.
>
What happened if the bootloader do not turn the regulator on?
I fear that in this case the regulator won't be turned on at all.
> A net advantage of using regulator-boot-on is that the regulator is
> not touched at boot time by the kernel, which avoids having the hard
> drives spinning down and then up again, taking several (~5) seconds of
> additional boot time.
>
> In addition, there is no need to have such properties on the child
> regulators used for SATA. Having it on the parent regulator that
> really controls the GPIO is sufficient.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> ---
> arch/arm/boot/dts/armada-388-gp.dts | 24 ++++++++----------------
> 1 file changed, 8 insertions(+), 16 deletions(-)
>
> diff --git a/arch/arm/boot/dts/armada-388-gp.dts b/arch/arm/boot/dts/armada-388-gp.dts
> index d8dab0f..1ef6cc6 100644
>
> @@ -309,7 +309,7 @@
> regulator-min-microvolt = <5000000>;
> regulator-max-microvolt = <5000000>;
> enable-active-high;
> - regulator-always-on;
> + regulator-boot-on;
> gpio = <&expander0 4 GPIO_ACTIVE_HIGH>;
> };
This node had been removed by a patch you sent few days ago:
"ARM: mvebu: remove duplicated regulator definition in Armada 388 GP"
Thanks,
Gregory
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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