[PATCH 1/2] mmc: dw_mmc: Handle late vmmc regulator with EPROBE_DEFER

[Tomasz Figa]

On Friday 07 of June 2013 11:24:04 Mark Brown wrote:
> On Fri, Jun 07, 2013 at 12:19:58PM +0200, Tomasz Figa wrote:
> > On Thursday 06 of June 2013 21:46:45 Doug Anderson wrote:
> > > dw_mmc is probed.  This regulator is optional, though a warning will
> > > be printed if it's missing.  The fact that the regulator is optional
> > > means that (at the moment) it's not possible to use a regulator that
> > > probes _after_ dw_mmc.
> > > 
> > > Fix this limitation by adding the ability to make vmmc required.  If
> > > a
> > > vmmc-supply is specified in the device tree we'll assume that vmmc
> > > is
> > > required.
> > 
> > This interesting case makes me think that regulator core should
> > differentiate between regulator lookup failure due to no lookup
> > specified and due to the regulator specified in lookup being
> > unavailable, returning appropriate (different) error codes.
> 
> It does exactly that in so far as it can - you get -ENODEV if there's
> definitely no supply and -EPROBE_DEFER otherwise.

Oh, right, thanks. I somehow felt that it should be doing this already, 
but I was looking at 3.9 on Free Electron's LXR. It does so since commit

1e4b545cdd regulator: core: return err value for regulator_get if there is 
no DT binding

so I think this patch should be reworked to check the returned error code 
instead.

Best regards,
Tomasz