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Message-ID: <20220117095559.GN18506@ediswmail.ad.cirrus.com> Date: Mon, 17 Jan 2022 09:55:59 +0000 From: Charles Keepax <ckeepax@...nsource.cirrus.com> To: Rob Herring <robh@...nel.org> CC: Peter Chen <peter.chen@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Linux USB List <linux-usb@...r.kernel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Arnd Bergmann <arnd@...db.de>, Tony Lindgren <tony@...mide.com> Subject: Re: ChipIdea USB regression On Mon, Jan 17, 2022 at 09:26:56AM +0000, Charles Keepax wrote: > On Sat, Jan 15, 2022 at 09:55:23AM -0600, Rob Herring wrote: > > On Fri, Jan 14, 2022 at 5:18 AM Charles Keepax > > <ckeepax@...nsource.cirrus.com> wrote: > > > On Fri, Jan 14, 2022 at 10:56:20AM +0000, Charles Keepax wrote: > > > So when that patch copies the DT node to the new platform device > > > in ci_hdrc_add_device it copies the compatible stuff as well as > > > the IRQ stuff it was targeting, this presumably causes the kernel > > > to bind a new copy of the driver to that new device, which probes > > > and calls ci_hdrc_add_device again repeating the process until > > > it dies. > > > > > > Kinda looks to me like the best solution might just be to revert > > > the patch, I am not sure I see how that copy of the DT is supposed > > > to work? > > > > It's not copying the DT, but yes AFAICT it does match and bind the > > child device on the parent driver using the compatible match instead > > of matching on driver name. I think we can use the of_reuse_node flag > > to avoid this in the match, but that needs some more investigation. > > Assuming you mean the of_node_reused flag, looks like it already > being set, your code does this: > > @@ -864,6 +864,7 @@ struct platform_device *ci_hdrc_add_device(struct device *dev, > pdev->dev.parent = dev; > + device_set_of_node_from_dev(&pdev->dev, dev); > > And that function does this: > > void device_set_of_node_from_dev(struct device *dev, const struct device *dev2) > { > of_node_put(dev->of_node); > dev->of_node = of_node_get(dev2->of_node); > dev->of_node_reused = true; > } > EXPORT_SYMBOL_GPL(device_set_of_node_from_dev); > > I guess maybe that flag doesn't do what it is supposed to for > some reason? > Ah ok it seems that flag is only currently used by the pinctrl subsystem, didn't realise that was quite so new and not used anywhere. I guess we probably need to add something to the platform device code to use that flag too, if that is the way we want to run with this. Thanks, Charles
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