[U-Boot] twl4030_power_init cleanup proposal

[Grazvydas Ignotas]

On Mon, Nov 30, 2009 at 6:17 PM, Tom <Tom.Rix at windriver.com> wrote:
> Grazvydas Ignotas wrote:
>>
>> hi,
>>
>> drivers/power/twl4030.c has a twl4030_power_init() function which is
>> called by most (all?) OMAP3 boards. What it does is enabling VAUX3,
>> VPLL2 and VDAC power supplies in TWL4030/TPS659x0 chip. However they
>> are all very board specific and in most cases not needed at all, at
>> least for booting the kernel. They also cause regulator warnings on
>> latest kernels.
>>
>> VAUX3: board specific, beagle doesn't have it connected at all, so it
>> wastes power there.
>> VPLL2: board specific, typically display related, as mainline u-boot
>> shows no graphics I think it can be removed.
>> VDAC: typically used to power TV-out DACs, can be removed. VDAC and
>> VPLL2 is already handled by kernel by DSS2.
>>
>> So I think VDAC, VPLL2 can be safely removed, probably VAUX3 too with
>> whole twl4030_power_init().
>>
>> Gražvydas
>
> Please provide specifics on the kernel warnings.
> These should be addressed.

regulator_init_complete: incomplete constraints, leaving VDAC on

This can be fixed in kernel itself by declaring regulators as
"boot_on" or "always_on", but I think it's better just to not turn
them on when they are not needed.

> The power setting should be done on board by board basis.
> If you are concerned about beagle, please provide a beagle specific
> patch.

ok will do that for pandora, as that's the hardware I have.

Gražvydas