On Fri, Jul 12, 2013 at 12:42:10PM +0300, Alexander Shishkin wrote: > Peter Chen <peter.chen@xxxxxxxxxxxxx> writes: > > > On Fri, Jul 12, 2013 at 11:12:01AM +0300, Alexander Shishkin wrote: > >> Peter Chen <peter.chen@xxxxxxxxxxxxx> writes: > >> > >> > Since we need otgsc to know vbus's status at some chipidea > >> > controllers even it is peripheral-only mode. Besides, some > >> > SoCs (eg, AR9331 SoC) don't have otgsc register even > >> > the DCCPARAMS_DC and DCCPARAMS_HC are both 1 at CAP_DCCPARAMS. > >> > We inroduce otg_cap attribute to indicate if the controller > >> > is otg capable, defaultly, we follow the rule that if DCCPARAMS_DC > >> > and DCCPARAMS_HC are both 1 at CAP_DCCPARAMS are otg capable, but if there > >> > is exception, the platform can override it by device tree or platform data. > >> > > >> > Signed-off-by: Peter Chen <peter.chen@xxxxxxxxxxxxx> > >> > --- > >> > >> [...] > >> > >> > diff --git a/include/linux/usb/chipidea.h b/include/linux/usb/chipidea.h > >> > index 118bf66..0a906b4 100644 > >> > --- a/include/linux/usb/chipidea.h > >> > +++ b/include/linux/usb/chipidea.h > >> > @@ -7,6 +7,12 @@ > >> > > >> > #include <linux/usb/otg.h> > >> > > >> > +enum usb_otg_cap { > >> > + OTG_CAP_ATTR_IS_NOT_EXISTED = 0, > >> > + OTG_CAP_ATTR_IS_TRUE, > >> > + OTG_CAP_ATTR_IS_FALSE, > >> > +}; > >> > >> We don't really need all three, do we? We only need to know if the > >> controller *can't* do otg. The rest we can infer from dr_mode and > >> DCCPARAMS. So it can be another bit in flags rather than a separate > >> field in platdata. > >> > > > > In order to cover below two cases, I have no other idea. > > > > 1. For mips Soc (ARxxx), if dr_mode = otg and it is 1 for both > > mode at DCCPARAMS, It can switch role through proc or whatever, > > but NO otgsc register, it is NOT otg-capable. > > For this case, platform should set > > platdata->flags &= CI_HDRC_NO_OTG > > , which will set ci->is_otg = false. No ci->is_otg => no touching > OTGSC. > > > 2. For peripheral-only case at most chipidea controllers, > > the dr_mode = peripheral and it is 1 for both modes at DCCPARAMS, > > the otgsc can be visited, it is otg-capable. > > Then platform *doesn't* set CI_HDRC_NO_OTG and ci->is_otg is set to > true, because DCCPARAMS.DC==1 and DCCPARAMS.HC==1, but we only have one > role initialized, because of dr_mode==peripheral, so no role switching > happens, but OTGSC accesses are fine. > > Makes sense? > Agree, I will add the define of CI_HDRC_NO_OTG to struct ci_hdrc_platform_data, and add below comments /* Only set it when DCCPARAMS.DC==1 and DCCPARAMS.HC==1, * but otg is not supported (no register otgsc). */ -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html