Re: [PATCH 1/6] Revert "regulator: core: Handle full constraints systems when resolving supplies"

From: Sascha Hauer
Date: Wed Sep 30 2015 - 14:48:21 EST

On Wed, Sep 30, 2015 at 07:02:13PM +0100, Mark Brown wrote:
> On Wed, Sep 30, 2015 at 03:57:49PM +0200, Sascha Hauer wrote:
> > This reverts commit 9f7e25edb1575a6d2363dc003f9cc09d840657e2.
> >
> > When a regulator A is registered and is supplied by regulator B which is
> > not yet registered then a regulator_get on regulator A will set the As
> > supply to the dummy regulator. This is not correct, we should return
> > -EPROBE_DEFER instead as done without this patch.
> What makes you say this is not correct? In a system with fully
> specified supplies if we fail to resolve the supply we know that no
> supply will ever appear and so substitute in the dummy on the assumption
> that there is a supply with no software control.

The situation I'm in is:

gpc: gpc@020dc000 {
compatible = "fsl,imx6q-gpc";
pu-supply = <&reg_pu>;

reg_pu: regulator-vddpu@140 {
compatible = "fsl,anatop-regulator";
vin-supply = <&vddsoc_reg>;


pmic@58 {
compatible = "dlg,da9063";
regulators {
vddsoc_reg: bcore2 {
regulator-min-microvolt = <730000>;
regulator-max-microvolt = <1380000>;

During boot the fsl,imx6q-gpc is probed and tries to get its regulator.
fsl,anatop-regulator is already registered, the dlg,da9063 is not. The
call to regulator_get tries to resolve the supply using
regulator_resolve_supply. regulator_resolve_supply then calls
regulator_dev_lookup which returns NULL because the supply (vddsoc_reg)
is specified in the device tree but not yet present. &ret is correctly
filled with -EPROBE_DEFER in this case, but this is ignored. Instead due
to 9f7e25edb157 the dummy regulator is used. This case worked before


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