Re: [PATCH] regulator: twl: Enable regulators over the powerbus as well

Ivaylo Dimitrov
2016-03-25T17:23:38Z

On 25.03.2016 19:05, Mark Brown wrote:
> On Fri, Mar 25, 2016 at 06:50:18PM +0200, Ivaylo Dimitrov wrote:
>> On 25.03.2016 18:19, Mark Brown wrote:
>
>>> What makes you claim that this is a bug in the framework? Does anything
>>> in the machine configuration say that changing the modes is allowed?
>
>> My understanding is that regulator core have to make sure an enabled
>> regulator to be in REGULATOR_STATUS_NORMAL. Now it enables the regulator,
>
> No, absolutely not. Modes are completely orthogonal to enabling and
> disabling the regulator - modes reflect an efficiency/accuracy tradeoff
> in the regulation, they are nothing to do with the regulator being
> enabled. Setting a mode should not affect the regulator enable state
> and enabling the regulator should not affect the mode.
>
>> It might be that I am not getting the logic behind.
>
> Yes, that seems to be the case.
>

Fair enough.

Now, what am I supposed to do to the fix the problem. Will try to
explain it in more details:

On Nokia N900 regulators are left in the mode last set by the bootloader
or by the stock kernel, depends on whether it is power-on or reboot from
stock kernel to mainline. That leads to problem with devices connected
to vmmc2 regulator - when the device is rebooted from stock kernel vmmc2
is left in "sleep" mode (REGULATOR_STATUS_STANDBY in terms of regulator
framework) and as noone in mainline kernel switches vmmc2 regulator to
normal (REGULATOR_STATUS_NORMAL) mode, devices supplied by it does not
get enough power to operate normally.