Re: [PATCH v2 3/5] Documentation: dt-bindings: Add snps,need-phy-for-wake for dwc2 USB

From: Felipe Balbi
Date: Thu Apr 25 2019 - 08:40:32 EST


Douglas Anderson <dianders@xxxxxxxxxxxx> writes:

> Some SoCs with a dwc2 USB controller may need to keep the PHY on to
> support remote wakeup. Allow specifying this as a device tree
> property.
>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---
> For relevant prior discussion on this patch, see:
>
> https://lkml.kernel.org/r/1435017144-2971-3-git-send-email-dianders@xxxxxxxxxxxx
>
> I didn't make any changes from the prior version since I never found
> out what Rob thought of my previous arguments. If folks want a
> change, perhaps they could choose from these options:
>
> 1. Assume that all dwc2 hosts would like to keep their PHY on for
> suspend if there's a USB wakeup enabled, thus we totally drop this
> binding. This doesn't seem super great to me since I'd bet that
> many devices that use dwc2 weren't designed for USB wakeup (they
> may not keep enough clocks or rails on) so we might be wasting
> power for nothing.
> 2. Rename this property to "snps,wakeup-from-suspend-with-phy" to make
> it more obvious that this property is intended both to document
> that wakeup from suspend is possible and that we need the PHY for
> said wakeup.
> 3. Rename this property to "snps,can-wakeup-from-suspend" and assume
> it's implicit that if we can wakeup from suspend that we need to
> keep the PHY on. If/when someone shows that a device exists using
> dwc2 where we can wakeup from suspend without the PHY they can add
> a new property.
>
> Changes in v2: None
>
> Documentation/devicetree/bindings/usb/dwc2.txt | 3 +++
> 1 file changed, 3 insertions(+)

checking file Documentation/devicetree/bindings/usb/dwc2.txt
Hunk #1 FAILED at 37.
Hunk #2 succeeded at 52 (offset -1 lines).
1 out of 2 hunks FAILED
--
balbi

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