[PATCH v5 01/23] driver core: Add pre_probe callback to bus_type

[Tomeu Vizoso]

On 17 September 2015 at 17:52, Alan Stern <stern at rowland.harvard.edu> wrote:
> On Thu, 17 Sep 2015, Tomeu Vizoso wrote:
>
>> Some buses (eg. AMBA) need access to some HW resources (it may need a
>> clock to be enabled so a device ID can be read) before a device can be
>> matched to a driver.
>>
>> The pre_probe callback allows the device-driver core to request the bus
>> to perform this initialization and can defer the probe if any of the
>> resources needed are missing.
>>
>> This gives us more flexibility when setting the order in which devices
>> are probed because the resources needed to get the matching information
>> don't need to be available by the time that the bus devices are
>> registered.
>
> Can't the subsystem do this itself in its matching routine?

That seems to work, thanks for the idea!

Regards,

Tomeu

> Alan Stern
>
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