linux-kernel - Re: [PATCH v2] dt: platform driver: Fill the resources before probe and defer if needed

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Message-ID: <CACh+v5M+0+C2JJwLqcp6erWa81kt=j1HucHiE52ufj1SO9F75w@mail.gmail.com>
Date:	Mon, 17 Mar 2014 16:20:03 +0100
From:	Jean-Jacques Hiblot <jjhiblot@...phandler.com>
To:	Grant Likely <grant.likely@...retlab.ca>
Cc:	Jean-Jacques Hiblot <jjhiblot@...phandler.com>,
	devicetree <devicetree@...r.kernel.org>,
	gregkh <gregkh@...uxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"robh+dt" <robh+dt@...nel.org>,
	Gregory CLEMENT <gregory.clement@...e-electrons.com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2] dt: platform driver: Fill the resources before probe
 and defer if needed

2014-03-17 15:24 GMT+01:00 Grant Likely <grant.likely@...retlab.ca>:
> On Mon, 17 Mar 2014 12:07:37 +0100, Jean-Jacques Hiblot <jjhiblot@...phandler.com> wrote:
>> Hi Grant,
>>
>> Sorry for the delay, I was having nice vacations.
>>
>> 2014-03-08 8:37 GMT+01:00 Grant Likely <grant.likely@...aro.org>:
>> > On Fri, 21 Feb 2014 14:18:40 +0100, Jean-Jacques Hiblot <jjhiblot@...phandler.com> wrote:
>> >> The goal of this patch is to allow drivers to be probed even if at the time of
>> >> the DT parsing some of their ressources are not available yet.
>> >
>> > Hi Jean-Jacques
>> >
>> > [...]
>> >> +int of_platform_device_prepare(struct platform_device *dev)
>> >> +{
>> >> +     struct device_node *np;
>> >> +     int i, irq_index;
>> >> +     struct resource *res;
>> >> +
>> >> +     /*
>> >> +      * This function applies only devices described in the DT.
>> >> +      * Other platform devices have their ressources already populated.
>> >> +      */
>> >> +     np = dev->dev.of_node;
>> >> +     if (!np)
>> >> +             return 0;
>> >
>> > I believe we already talked about the above test. This function must
>> > only process devices created by of_platform_populate(). Merely checking
>> > the of_node pointer is not a sufficient test because there are other
>> > paths in the kernel for creating platform_devices that might get a node
>> > pointer attached to it.
>> Yes we talked about this, but only to move it into of_platform_device_prepare().
>> Is there an existing way to know for sure that the device has been
>> created by of_platform_populate() ? I could not find one.
>
> No there isn't. That information is used at population time and then
> discarded. We'd need to add a flag or registry to mark those devices.
OK. As I see it, this could be done either by adding a new flag to
struct device or by maintaining a private list of "of created" devices
in of/platform.c.
I favor modifying struct device as it's is by far the simplest but
it's also more intrusive. Any advice ?

Jean-Jacques

>
> g.
>
>>
>> Jean-Jacques
>> >
>> > g.
>> >
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
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