Re: USB_DWC3_OF_SIMPLE

[Felipe Balbi <balbi@kernel.org>]

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Hi,

Jonathan Thibault <jonathan@navigue.com> writes:

> Greetings,
>
> I am currently trying to port OpenWRT to Ubiquiti's EdgeRouter 4 which 
> is a Cavium Octeon 7130.  While investigating to support XHCI (the 
> device has a single USB3 port), I ran into the dwc3 driver which 
> apparently supports that very chipset via the dwc3-of-simple glue.
>
> Looking at Ubiquiti's own firmware, it seems they are using a modified 
> version of the standard xhci-platform driver.
>
> So now I am faced with two different approaches:
>
> 1- Attempt to replicate Ubiquiti's modifications to xhci-plat.
>
> 2- Switch to dwc3-of-simple.
>
> With option 1, so far, I can get xhci to load by merely adding a 
> '.compatible =' member to usb_xhci_of_match[], but the driver complains 
> about LPM algorithms and disables LPM (which may be fine, I don't know 
> if it is even supported on this device).
>
> Option 2 (where you might hopefully help), potentially involves more 
> modification to the OpenWRT since their Octeon kernel config does not 
> appear to enable CONFIG_COMMON_CLK, which the driver depends on.  And I 
> do not know if I should also disable standard ohci and ehci drivers once 
> I manage to enable the USB_DWC3_OF_SIMPLE.
>
> I'm looking for recommendations on the best approach.  Keep in mind that 
> while I can cobble together some ugly but functional hacks, I am not an 
> experienced kernel dev.

Just switch to dwc3-of-simple, it already supports the SoC you're
dealing with. Try removing the dependency on CONFIG_COMMON_CLK. I think
we already get empty stubs when common clk is disabled.

If that works for you, that's an easy patch.

-- 
balbi

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