Hi, On Wednesday 05 April 2017 07:40 PM, Raviteja Garimella wrote: > Hi Kishon, > > On Wed, Apr 5, 2017 at 7:04 PM, Kishon Vijay Abraham I <kishon@xxxxxx> wrote: >> Hi Ravi, >> >> On Wednesday 05 April 2017 06:30 PM, Raviteja Garimella wrote: >>> Hi Kishon, >>> >>> On Wed, Apr 5, 2017 at 4:30 PM, Kishon Vijay Abraham I <kishon@xxxxxx> wrote: >>>> Hi, >>>> >>>> On Tuesday 28 March 2017 05:57 PM, Raviteja Garimella wrote: >>>>> This is driver for USB DRD Phy used in Broadcom's Northstar2 >>>>> SoC. The phy can be configured to be in Device mode or Host >>>>> mode based on the type of cable connected to the port. The >>>>> driver registers to extcon framework to get appropriate >>>>> connect events for Host/Device cables connect/disconnect >>>>> states based on VBUS and ID interrupts. >>>> >>>> $patch should be phy: phy-bcm-ns2-usbdrd: USB DRD Phy driver for Broadcoms >>>> Northstar2. >>>> >>> >>> Will do. >>> >>>> Sorry for not letting you know this earlier. But I feel the design of the >>>> driver should be changed. Extcon shouldn't be used here. The extcon >>>> notifications should be sent to the consumer driver and the consumer driver >>>> should be responsible for invoking the phy ops. >>>> >>> >>> The consumer drivers here would be a UDC driver (USB device >>> controller), EHCI and OHCI host controller drivers. >>> I was already suggested in UDC driver review to deal with extcon in Phy driver. >>> >>> This phy connects to 2 host controllers, and one device controller. >>> That's the design in Broadcom Northstar2 >>> platform. The values of the VBUS and ID pins of this port are >>> determined based on the type of the cable (device cable >>> or host cable). And. phy has to be configured accordingly. >>> >>>> The phy ops being invoked during extcon events doesn't look right. >>> >>> Could you please elaborate on the concern, so that we can think of >>> mitigating those issues in this driver? >>> Since we are dealing with phy init/shutdown in this driver itself, are >>> you okay with moving the extcon handling code >>> out of phy ops ? >> >> yeah, For e.g., ns2_drd_phy_init is part of phy_ops and is being invoked from >> extcon events too. Can a phy which is initialized by a phy consumer (say your >> UDC invokes phy_init) can be shutdown by an extcon event? >> >> Maybe a clear explanation of when phy_ops here will be invoked and when it will >> set using extcon events might help. >> > > Say, we have a USB pendrive which is connected to the DRD port through > a host cable. > Now the PHY will be initialized to be in host mode. > When the pendrive is unplugged, and we now connect the NS2 device to > some linux PC, > now the PHY has to be shutdown, and re-initialized to be in Device mode. > > On unplug event, it is set neither to Host nor Device mode (basically > shutdown). Next time which ever cable is connected, the PHY is > initialized to the respective > mode. > > Please let me know if it's fine to do these initializations outside > phy ops, because those will > be irrelevant for phy consumers (the controllers) as it's anyways > dealt in the phy driver through > extcon. Yes. We shouldn't add phy_ops just for the sake of it. I think this should be made as a purely extcon driver (though there are a couple of bits that looks like initializing PHY) and keep it in drivers/extcon. Thanks Kishon -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
