linux-kernel - Re: Regulator probe

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Date:   Fri, 09 Sep 2016 15:55:27 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Hunter, Adrian" <adrian.hunter@...el.com>
Subject: Re: Regulator probe

On Fri, 2016-09-09 at 13:17 +0100, Mark Brown wrote:
> On Wed, Sep 07, 2016 at 05:24:01PM +0300, Andy Shevchenko wrote:
> > 
> > On Tue, 2016-09-06 at 11:24 +0100, Mark Brown wrote:
> 
> > 
> > > 
> > > Nothing says you have to describe all regulators, you just need to
> > > tell the core you have told it about everything you're going to
> > > tell
> > > it about.  Until you do that the core has to assume that something
> > > may
> > > come along later and describe that supply.
> 
> > 
> > That's I would like to make work. For now we have fixed voltage
> > regulator which returns EPROBE_DEFER since GPIO IP is not
> > initialized
> > yet at that point. But regulator framework decides that it's not
> > possible case and overrides the error code.
> 
> What do you mean?  Of course we should handle probe deferral if we
> fail to get a resource like a GPIO.  Are you trying to say that this
> doesn't work for you?

No, it doesn't.

Fixed regulator probe is deferred:

reg-fixed-voltage reg-fixed-voltage.0.auto: Failed to register
regulator: -517

But:
sdhci-pci 0000:00:01.3: No vmmc regulator found

Code in sdhci driver is:
        ret = mmc_regulator_get_supply(mmc);
        if (ret == -EPROBE_DEFER)
                return ret;

mmc_regulator_get_supply():
...
        mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
        mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");

        if (IS_ERR(mmc->supply.vmmc)) {
                if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
                        return -EPROBE_DEFER;
                dev_dbg(dev, "No vmmc regulator found\n");
...


So _regulator_get() returns something else than -EPROBE_DEFER.


-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy