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SubjectRe: [PATCH] sunxi-rsb: Include OF based modalias in device uevent
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On Monday, November 27, 2017 4:35:02 PM CET Maxime Ripard wrote:
> Hi,
>
> On Mon, Nov 27, 2017 at 01:17:25PM +0100, Stefan Brüns wrote:
> > Include the OF-based modalias in the uevent sent when registering devices
> > on the sunxi RSB bus, so that user space has a chance to autoload the
> > kernel module for the device.
> >
> > Fixes a regression caused by commit 3f241bfa60bd ("arm64: allwinner: a64:
> > pine64: Use dcdc1 regulator for mmc0"). When the axp20x-rsb module for
> > the AXP803 PMIC is built as a module, it is not loaded and the system
> > ends up with an disfunctional MMC controller.
> >
> > Cc: stable <stable@vger.kernel.org>
> > Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
> > ---
> >
> > drivers/bus/sunxi-rsb.c | 13 +++++++++++++
> > 1 file changed, 13 insertions(+)
> >
> > diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c
> > index 328ca93781cf..37cb57244cbe 100644
> > --- a/drivers/bus/sunxi-rsb.c
> > +++ b/drivers/bus/sunxi-rsb.c
> > @@ -173,11 +173,24 @@ static int sunxi_rsb_device_remove(struct device
> > *dev)>
> > return drv->remove(to_sunxi_rsb_device(dev));
> >
> > }
> >
> > +static int sunxi_rsb_device_uevent(struct device *dev,
> > + struct kobj_uevent_env *env)
> > +{
> > + int ret;
> > +
> > + ret = of_device_uevent_modalias(dev, env);
> > + if (ret != -ENODEV)
> > + return ret;
>
> A comment explaining why we need to ignore the ENODEV error code would
> be great here.

Lazy answer - everyone else is doing the same, and nobody cared to add an
explanation.

For *some* drivers, this is likely because the same device may be enumerated
from e.g ACPI or OF, and for an ACPI device -ENODEV will be returned, as
dev->of_node is NULL.

For devices which are only usable in an OF context, this is bogus. Not sure
about sunxi-rsb.

> > + return 0;
> > +}
> > +
> >
> > static struct bus_type sunxi_rsb_bus = {
> >
> > .name = RSB_CTRL_NAME,
> > .match = sunxi_rsb_device_match,
> > .probe = sunxi_rsb_device_probe,
> > .remove = sunxi_rsb_device_remove,
> >
> > + .uevent = sunxi_rsb_device_uevent,
>
> Any reason to not use of_device_uevent_modalias directly here?

*If* sunxi-rsb can be used without OF, then yes, otherwise no.

Regards,

Stefan

--
Stefan Brüns / Bergstraße 21 / 52062 Aachen
home: +49 241 53809034 mobile: +49 151 50412019[unhandled content-type:application/pgp-signature]
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