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Sergei Shtylyov wrote:
> Hello.
> 
> Yusuf Caglar AKYUZ wrote:
>>> i'm trying to get an USB-stick running on a DVEVM-alike
>>> hardware on a recent kernel, but the USB host appears
>>> to be plain dead.
>>>
>>> I've digged a little into the kernel and my result is, that
>>> 'platform_driver_probe' in the end of 'musb_init' never
>>> ends calling 'musb_probe', thus resulting in the musb_driver
>>> being deregistered and ignored by the kernel.
>>>
>>> Digging deeper, the 'platform_driver_probe' enumerates the
>>> 'platform' bus but fails to find any suiting device. Thus, from
>>> the sources, it appears as if the construction misses a
>>> 'platform_device' representing the USB host controller.
>>>
>>> Because only the kernel and no hardware appears to be involved,
>>> it looks like a silly kernel configuration problem to me. I write to
>>> ask if someone knows the solution or could otherwise help.
>>>
>>> I can produce the result with 'davinci_evm_dm644x_defconfig'.
>> You said DVEVM-alike, does it have i2c port expander as well for
>> VBUS control?
>>   
> 
>   There's  much more wisdom in controlling DRVVBUS via plain GPIO than
> this horrible GPIO expander thing.
> 

Absolutely.

In fact we're using GPIO in our own boards and:

1) DRVVBUS control must be board specific.
2) Simply passing GPIO with platform data is not enough because
   polarity may even change.
3) I guess we don't need a workqueue for direct GPIO control.

What is the best way to achieve these goals? Passing a function
pointer via platform data to handle pin control at board* files, or
passing GPIO number and polarity via platform data while using
workqueue for all the cases?

Regards,
Caglar
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