linux-kernel - Re: [PATCH v2] mfd: syscon: allow to register syscon with a device

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Message-ID: <2637460.3ZCmmf9MXm@wuerfel>
Date:	Wed, 24 Feb 2016 17:26:46 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Philipp Zabel <p.zabel@...gutronix.de>
Cc:	Lee Jones <lee.jones@...aro.org>,
	Alexander Shiyan <shc_work@...l.ru>,
	Pankaj Dubey <pankaj.dubey@...sung.com>,
	Pawel Moll <pawel.moll@....com>,
	Wolfram Sang <wsa@...-dreams.de>,
	Peter Seiderer <ps.report@....net>,
	Tushar Behera <tushar.behera@...aro.org>,
	linux-kernel@...r.kernel.org, kernel@...gutronix.de
Subject: Re: [PATCH v2] mfd: syscon: allow to register syscon with a device

On Wednesday 24 February 2016 16:02:28 Philipp Zabel wrote:
> > > @@ -473,6 +474,12 @@ static const struct of_device_id imx6q_pinctrl_of_match[] = {
> > >  
> > >  static int imx6q_pinctrl_probe(struct platform_device *pdev)
> > >  {
> > > +       struct device_node *syscon_np;
> > > +
> > > +       syscon_np = of_find_compatible_node(NULL, NULL, "fsl,imx6q-iomuxc-gpr");
> > > +       if (syscon_np)
> > > +               syscon_register(&pdev->dev, syscon_np);
> > > +
> > >         return imx_pinctrl_probe(pdev, &imx6q_pinctrl_info);
> > >  }
> > >  
> > > The pinctrl driver is probed at arch_initcall time.
> > 
> > I still don't see it where you are getting with this. Is this just for
> > the debugfs interface or is there something else this does on top of
> > that?
> 
> Sorry, yes, this is about the missing debugfs functionality.

Ok, so maybe there is a different way of doing this: If I understood
it correctly, we now lost the debugfs handling on all syscon nodes?

Should we try to come up with a way to bring it back for all of them
then, rather than having to do it per device?

I can see two possible ways of doing that:

a) change the regmap code to provide a debugfs interface for all
   regmaps, including those without a device
b) change the syscon driver to explicitly register the debugfs
   interface at a later point in boot when the devices become
   available

	Arnd