Hi, On Monday 10 April 2017 12:57 PM, Raviteja Garimella wrote: > Hi, > > On Mon, Apr 10, 2017 at 10:55 AM, Kishon Vijay Abraham I <kishon@xxxxxx> wrote: >> 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. >> >> How does the consumer get to know whether they have to operate in host mode or >> device mode? >> > In NS2, we have host controllers and device controller (not OTG/other > that can switch > between host and device mode). It's only phy that can be in host/device mode. > Since both Host Controllers and Device Controller are connected to the same PHY, > it is based on the extcon logic (the type of cable connected) that PHY > will be in one > of the modes host/device and the respective controller will operate. So at a point of time either the host controller or the device controller will be active? and the PHY decides which of them should be active? Is that right? 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
