[PATCH 1/3] mmc: dw_mmc: use mmc_regulator_get_supply to handle regulators

[Seungwon Jeon]

On Fri, June 27, 2014, Doug Anderson wrote:
> Seungwon,
> 
> On Thu, Jun 26, 2014 at 3:30 AM, Seungwon Jeon <tgih.jun at samsung.com> wrote:
> > Hi Doug,
> >
> > On Thu, June 26, 2014, Doug Anderson wrote:
> >> Seungwon,
> >>
> >> On Wed, Jun 25, 2014 at 4:18 AM, Seungwon Jeon <tgih.jun at samsung.com> wrote:
> >> >> >> +       case MMC_POWER_ON:
> >> >> >> +               if (!IS_ERR(mmc->supply.vqmmc) &&
> >> >> >> +                               !test_bit(DW_MMC_IO_POWERED, &slot->flags)) {
> >> > You can use regulator_is_enabled() instead of flag bit, DW_MMC_IO_POWERED.
> >>
> >> I'd be a little worried about regulator_is_enabled() since regulators
> >> are reference counted.  What if someone else is sharing this
> >> regulator?  The regulator might happen to be enabled when you check it
> >> but unless you add your own dw_mmc reference count they might turn it
> >> off.
> > Cool, that's a possibility. Some assumption may need.
> > If mmc's core can guarantee its balance, I think we don't need to consider some flag.
> 
> I notice that the mmc core seems to keep a flag itself for vdd (the
> mmc->regulator_enabled flag).  That would imply that the core thought
> it was important to have the extra flag and that we should keep our
> own flag for vqmmc.
Ok, Good.

Thanks,
Seungwon Jeon
> 
> -Doug
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