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

From: Jean-Jacques Hiblot
Date: Mon Mar 17 2014 - 11:20:31 EST


2014-03-17 15:24 GMT+01:00 Grant Likely <grant.likely@xxxxxxxxxxxx>:
> On Mon, 17 Mar 2014 12:07:37 +0100, Jean-Jacques Hiblot <jjhiblot@xxxxxxxxxxxxxxx> wrote:
>> Hi Grant,
>>
>> Sorry for the delay, I was having nice vacations.
>>
>> 2014-03-08 8:37 GMT+01:00 Grant Likely <grant.likely@xxxxxxxxxx>:
>> > On Fri, 21 Feb 2014 14:18:40 +0100, Jean-Jacques Hiblot <jjhiblot@xxxxxxxxxxxxxxx> 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.
>> >
>>
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>
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