[3/3] usb: dwc3: Support option to disable USB2 LPM

[Felipe Balbi <balbi@kernel.org>]

Hi,

Oliver Neukum <oneukum@suse.com> writes:
>> > > --- a/drivers/usb/dwc3/core.h
>> > > +++ b/drivers/usb/dwc3/core.h
>> > > @@ -971,6 +971,7 @@ struct dwc3_scratchpad_array {
>> > >   * @setup_packet_pending: true when there's a Setup Packet in FIFO. Workaround
>> > >   * @three_stage_setup: set if we perform a three phase setup
>> > >   * @usb3_lpm_capable: set if hadrware supports Link Power Management
>> > > + * @usb2_lpm_disable: set to disable usb2 lpm
>> > >   * @disable_scramble_quirk: set if we enable the disable scramble quirk
>> > >   * @u2exit_lfps_quirk: set if we enable u2exit lfps quirk
>> > >   * @u2ss_inp3_quirk: set if we enable P3 OK for U2/SS Inactive quirk
>> > > @@ -1146,6 +1147,7 @@ struct dwc3 {
>> > >         unsigned                setup_packet_pending:1;
>> > >         unsigned                three_stage_setup:1;
>> > >         unsigned                usb3_lpm_capable:1;
>> > > +       unsigned                usb2_lpm_disable:1;
>> > 
>> > Hi,
>> > 
>> > that may be a bit late, but why would this be a property of dwc3?
>> > Now, you may want to do this for a specific controller,
>> > but there is no reason to limit the flag to dwc3. We want this
>> > flag in the generic HCD attributes, so that other HCDs can share
>> > it. Maybe even expose it to sysfs.
>> 
>> this is used for the peripheral side of dwc3 too.
>
> same argument. Whether a gadget supports LPM is a question
> in no way specific to dwc3. And whether this exposes internal
> registers does not really matter. It is a capability of the HC
> for a generic issue.

for the gadget api we don't have enough UDCs supporting LPM to design a
proper generic api. Until then, it's best to keep this private to the
driver otherwise we may make the wrong decisions in the generic layer.