Hi Felipe-san,
> From: Felipe Balbi, Sent: Wednesday, March 29, 2017 5:03 PM
>
> Yoshihiro-san
>
> Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> writes:
> >> >> Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> writes:
> >> >> > Sadly, to change the role ("host" and "peripheral") of USB3.0 DRD
> >> >> > controller on R-Car Gen3, software has to set the DRD_CON register
> >> >> > which is included in a usb3.0 peripheral controler's register.
> >> >> > To simply implementation, the previous code always set peripheral mode
> >> >> > as hardcoded. However, to support usb role swap in the future,
> >> >> > the hardcoded is not good. So, this patch adds sysfs "role" to set
> >> >> > the mode by a user.
> >> >> > After applied this patch, since the DRD controller will act as host
> >> >> > mode after probed, a user needs to change the mode via the sysfs.
> >> >> >
> >> >> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> >> >>
> >> >> in patch 3, you add extcon to monitor ID and VBUS pins. Do you really
> >> >> need this sysfs file at all?
> >> >
> >> > Yes. This is because this "role" sysfs file cannot monitor the ID and VBUS pins.
> >> > The "role" only monitors the mode which is "host" or "peripheral".
> >>
> >> Right, I understand it can't monitor the state of ID/VBUS, but do you
> >> have a usecase for that file that's not covered by the other patches in
> >> the series? :-)
> >
> > Thank you for the comment. Since my English skill is not good,
> > I don't understand your question.
>
> oh, that's alright. I'll try to explain:
>
> I'm asking if you have any situation where you need userspace to change
> the role manually. I understand it's a very nice feature to have during
> development because it frees us from searching for "the right cable";
> but if the only application of this sysfs file is durinb development,
> then perhaps it should be exposed using debugfs instead ;-)
>
> Hopefully that's easier to understand now.
Thank you for the explanation! I understood this :)
This "b-device" mode is totally for development purpose.
- The old version SoC has a restriction (cannot monitor ID pin!),
So even if a board has B connector, I should turn the mode to peripheral.
- I would like to develop this driver using A connector on a board that is related
to SoC and board environment specification :)
So, I think this code is low priority thing for now.
Thus, I will remove this patch 1 and rebase other patches and resubmit later today.
Best regards,
Yoshihiro Shimoda
> --
> balbi
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