On 06/22/2019 11:11 PM, Mark Kettenis wrote:
>> From: Jagan Teki <ja...@amarulasolutions.com>
>> Date: Sat, 22 Jun 2019 20:17:13 +0530
>>
>> On Sat, Jun 22, 2019 at 2:46 AM Mark Kettenis <kette...@openbsd.org> wrote:
>>> Add missing regulator-init-microvolt property to vdd_log regulator.
>>>
>>> Signed-off-by: Mark Kettenis <kette...@openbsd.org>
>>> ---
>>> Without this property the pwm regulator driver prints a warning and
>>> the OpenBSD kernel crashes shortly after spinning up the big cores.
>>>
>>> arch/arm/dts/rk3399-rockpro64-u-boot.dtsi | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/arch/arm/dts/rk3399-rockpro64-u-boot.dtsi
>>> b/arch/arm/dts/rk3399-rockpro64-u-boot.dtsi
>>> index dbfa4ba9f8..f7f26d584f 100644
>>> --- a/arch/arm/dts/rk3399-rockpro64-u-boot.dtsi
>>> +++ b/arch/arm/dts/rk3399-rockpro64-u-boot.dtsi
>>> @@ -5,3 +5,7 @@
>>>
>>> #include "rk3399-u-boot.dtsi"
>>> #include "rk3399-sdram-lpddr4-100.dtsi"
>>> +
>>> +&vdd_log {
>>> + regulator-init-microvolt = <950000>;
>>> +};
>> This seems to be issue on whole? how does Linux work? if it required
>> in Linux better make a change there and sync here.
This is a pwm regulator, need to init in U-Boot instead of in kernel,
or else the kernel may hang in the regulator init.
And this pwm regulator suppose to be init with regulators_enable_boot_on().
I would apply the fix first with a rebase without lpddr4 patch set.
Applied to u-boot-rockchip/master.
Thanks,
- Kever
> It needs the fix to actually turn on the boot-on regulators as well.
> But yes, with this property in the device tree, U-Boot enables the
> regulator with the appropriate voltage and the crash I'm seeing is gone.
>
> I deliberately made this change in the rk3399-rockpro64-u-boot.dtsi
> file since the "regulator-init-microvolt" property is *not* defined by
> the Linux devicetree bindings. So I expect that a patch to change
> this in the Linux device tree would be rejected.
>
> Note that this regulator has a "regulator-boot-on" property. So Linux
> doesn't need to know the initial setting of this regulator as the
> bootloader/firmware is supposed to set it up.
>
> I don't know if folks running Linux are experiencing problems as wll;
> I don't run Linux on my boards ;). I suspect very few people are
> actually using mainline U-Boot on their boards. But it is also
> possible that the Linux kernel does enable this regulator when it
> boots, since it sees that it hasn't been enabled. It does have some
> fallback code to fix that up in case the bootloader/firmware didn't do
> things properly. But what voltage would it use?
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