From mboxrd@z Thu Jan 1 00:00:00 1970 From: gregory.clement@free-electrons.com (Gregory CLEMENT) Date: Tue, 04 Aug 2015 15:08:36 +0200 Subject: MUSB dual-role on AM335x behaving weirdly In-Reply-To: References: <20150514190429.GT24269@saruman.tx.rr.com> <20150514192125.GU24269@saruman.tx.rr.com> <20150514192946.GV24269@saruman.tx.rr.com> <20150514212653.GC3338@piout.net> <20150526145118.GD26599@saruman.tx.rr.com> <20150527094205.GO3199@piout.net> <5594E56B.3040200@free-electrons.com> Message-ID: <55C0B954.3020106@free-electrons.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Bin, On 02/07/2015 19:05, Bin Liu wrote: > Hi, > > On Thu, Jul 2, 2015 at 2:16 AM, Gregory CLEMENT > wrote: >> Hi Felipe, >> >> On 27/05/2015 11:42, Alexandre Belloni wrote: >>> Hi, >>> >>> On 26/05/2015 at 09:51:18 -0500, Felipe Balbi wrote : >>>> On Thu, May 14, 2015 at 04:36:33PM -0500, Bin Liu wrote: >>>>> Alexandre, >>>>> >>>>> On Thu, May 14, 2015 at 4:26 PM, Alexandre Belloni >>>>> wrote: >>>>>> On 14/05/2015 at 16:16:12 -0500, Bin Liu wrote : >>>>>>> I think I found the root cause of the problem: board design issue - I >>>>>>> bet the custom board has too much cap on VBUS line. It should be < >>>>>>> 10uF. >>>>>>> >>>>>> >>>>>> We have a custom board that exhibits the issue but it only has a 100nF >>>>>> cap on VBUS. >>>>> >>>>> Have you measured the VBUS discharging? Is there any way to share your >>>>> schematics? >>>> >>>> Alexandre, any further comments ? >>>> >>> >>> Yeah, I have just got more info. >>> >>> This is the relevant part of the schematic: >>> http://free-electrons.com/~alexandre/usb.png >>> >>> The total VBUS capacitance is 200nF and the USB0 pins are connected >>> directly to the AM3358 pins. U1 is actually not fitted. >>> >>> We didn't measure VBUS discharging but we observe the OTG pin sensing >>> stops when plugging an OTG cable without any device. >> >> Do you have any news about this topic? >> >> >> Is there something else that we can do to help solving this issue? > > In the case of CONFIG_USB_MUSB_DUAL_ROLE=y and dr_mode=otg, how is the > gadget driver configured? It has to be a module not built-in. Indeed when I configured CONFIG_USB_MUSB_HDRC=m and CONFIG_USB_MUSB_DSPS=m it worked seamless. Thanks, Gregory > > Regards, > -Bin. > >> >> >> Thanks, >> >> Gregory >> >> >> -- >> Gregory Clement, Free Electrons >> Kernel, drivers, real-time and embedded Linux >> development, consulting, training and support. >> http://free-electrons.com -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com