linux-kernel - Re: [PATCH RFT/RFC] mfd: cs42l43: setup true links with software nodes

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Message-ID: <CAMRc=MdYcdrQSDWKDHrx4-Y4-y92AQqr73MoRC3ws-X==SL0MA@mail.gmail.com>
Date: Wed, 19 Nov 2025 12:06:57 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Charles Keepax <ckeepax@...nsource.cirrus.com>, David Rhodes <david.rhodes@...rus.com>, 
	Richard Fitzgerald <rf@...nsource.cirrus.com>, Lee Jones <lee@...nel.org>, 
	Mark Brown <broonie@...nel.org>, Philipp Zabel <p.zabel@...gutronix.de>, 
	Linus Walleij <linus.walleij@...aro.org>, Maciej Strozek <mstrozek@...nsource.cirrus.com>, 
	Andy Shevchenko <andy@...nel.org>, linux-sound@...r.kernel.org, 
	patches@...nsource.cirrus.com, linux-kernel@...r.kernel.org, 
	linux-spi@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH RFT/RFC] mfd: cs42l43: setup true links with software nodes

On Wed, Nov 19, 2025 at 11:58 AM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Wed, Nov 19, 2025 at 11:50:09AM +0100, Bartosz Golaszewski wrote:
> > On Wed, Nov 19, 2025 at 11:47 AM Charles Keepax
> > <ckeepax@...nsource.cirrus.com> wrote:
> > > On Wed, Nov 19, 2025 at 11:38:35AM +0100, Bartosz Golaszewski wrote:
>
> ...
>
> > > Cool, thanks for all your help here. Might take me a couple hours
> > > but I will get to the bottom of the EBUSY thing, and report back.
> >
> > Sure. Could you just post the stack trace down to where the EBUSY is
> > returned in drivers/base/swnode.c? I'd like to analyze the logic
> > myself too if that's not too much work for you.
>
>
> FWIW, there is also an interesting debug technique. Put in your driver where
> you get this error code something like this (after all #include directives):
>
> #undef EBUSY
> #define EBUSY __LINE__
>
> And then you get some error code which is line number in some C file. You can
> narrow down grepping of the EBUSY in the suspected files and get the one.
>
>         git grep -n -w EBUSY -- ...files of interest...
>
> Hope this saves some minutes for you.
>

Charles confirmed he gets it from device_add_software_node(). I want
to know how we're getting there and how we could end up already having
a software node.

Bartosz