Re: [PATCH v6 3/5] of/platform: Add stubs for of_platform_device_create/destroy()

From: Matthias Kaehlcke <mka@chromium.org>
To: Rob Herring <robh@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alan Stern <stern@rowland.harvard.edu>,
	Frank Rowand <frowand.list@gmail.com>,
	Ravi Chandra Sadineni <ravisadineni@chromium.org>,
	Peter Chen <peter.chen@nxp.com>,
	Michal Simek <michal.simek@xilinx.com>,
	Stephen Boyd <swboyd@chromium.org>,
	linux-kernel@vger.kernel.org, Bastien Nocera <hadess@hadess.net>,
	linux-usb@vger.kernel.org,
	Douglas Anderson <dianders@chromium.org>,
	devicetree@vger.kernel.org, Krzysztof Kozlowski <krzk@kernel.org>
Subject: Re: [PATCH v6 3/5] of/platform: Add stubs for of_platform_device_create/destroy()
Date: Tue, 9 Mar 2021 09:20:12 -0800	[thread overview]
Message-ID: <YEeuTBsU145OTSCk@google.com> (raw)
In-Reply-To: <20210308223251.GA3067045@robh.at.kernel.org>

On Mon, Mar 08, 2021 at 03:32:51PM -0700, Rob Herring wrote:
> On Fri, Mar 05, 2021 at 11:38:51AM -0800, Matthias Kaehlcke wrote:
> > Code for platform_device_create() and of_platform_device_create() is
> 
> You mean of_platform_device_create and of_platform_device_destroy?
> 
> Does of_platform_populate not work in your usecase?

of_platform_populate() would create a platform device for every node
under the USB controller or hub. While this could be restricted with
the 'matches' parameter it would still create two platform devices for
a hub controller that provides separate USB 2 and USB 3 hubs.

When of_platform_device_create() is used the onboard hub driver can
help to decide for which node the platform device should be created.

> > only generated if CONFIG_OF_ADDRESS=y. Add stubs to avoid unresolved
> > symbols when CONFIG_OF_ADDRESS is not set.
> > 
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > ---
> > 
> > Changes in v6:
> > - patch added to the series
> > 
> >  include/linux/of_platform.h | 22 ++++++++++++++++++----
> >  1 file changed, 18 insertions(+), 4 deletions(-)
> > 
> > diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h
> > index 84a966623e78..d15b6cd5e1c3 100644
> > --- a/include/linux/of_platform.h
> > +++ b/include/linux/of_platform.h
> > @@ -61,16 +61,18 @@ static inline struct platform_device *of_find_device_by_node(struct device_node
> >  }
> >  #endif
> >  
> > +extern int of_platform_bus_probe(struct device_node *root,
> > +				 const struct of_device_id *matches,
> > +				 struct device *parent);
> > +
> > +#ifdef CONFIG_OF_ADDRESS
> >  /* Platform devices and busses creation */
> >  extern struct platform_device *of_platform_device_create(struct device_node *np,
> >  						   const char *bus_id,
> >  						   struct device *parent);
> >  
> >  extern int of_platform_device_destroy(struct device *dev, void *data);
> > -extern int of_platform_bus_probe(struct device_node *root,
> > -				 const struct of_device_id *matches,
> > -				 struct device *parent);
> > -#ifdef CONFIG_OF_ADDRESS
> > +
> >  extern int of_platform_populate(struct device_node *root,
> >  				const struct of_device_id *matches,
> >  				const struct of_dev_auxdata *lookup,
> > @@ -84,6 +86,18 @@ extern int devm_of_platform_populate(struct device *dev);
> >  
> >  extern void devm_of_platform_depopulate(struct device *dev);
> >  #else
> > +/* Platform devices and busses creation */
> > +static inline struct platform_device *of_platform_device_create(struct device_node *np,
> > +								const char *bus_id,
> > +								struct device *parent)
> > +{
> > +	return NULL;
> > +}
> > +static inline int of_platform_device_destroy(struct device *dev, void *data)
> > +{
> > +	return -ENODEV;
> > +}
> > +
> >  static inline int of_platform_populate(struct device_node *root,
> >  					const struct of_device_id *matches,
> >  					const struct of_dev_auxdata *lookup,
> > -- 
> > 2.30.1.766.gb4fecdf3b7-goog
> > 