Hi, On Mon, Apr 10, 2017 at 2:07 PM, 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. > > 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. > Actually phy_ops would be required when we want phy to be shutdown/init during power management, where USB controllers would call them. I reworked on this driver to address the concerns raised here. Please check PATCH v5 that I will submit shortly. If we want to dynamically change the mode of PHY either to be in host mode or device mode or idle, we don't have to do a full PHY init/power on (that earlier required doing a PHY PLL lock and other resets). We just have to program couple of register bits that are dedicated for this purpose. I made those changes, now we don't have to call phy ops in the driver. Phy_ops will be called only by the consumer drivers. Thanks, Ravi > 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
