Messages in this thread | | | Date | Wed, 03 Apr 2019 17:31:31 +0200 | From | Paul Cercueil <> | Subject | Re: [PATCH] usb: musb: Force-disable pullup on shutdown |
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Le mer. 3 avril 2019 à 15:26, Bin Liu <b-liu@ti.com> a écrit : > On Tue, Apr 02, 2019 at 09:58:42PM +0200, Paul Cercueil wrote: >> Hi, >> >> Le lun. 1 avril 2019 à 20:20, Bin Liu <b-liu@ti.com> a écrit : >> >On Mon, Apr 01, 2019 at 07:46:22PM +0200, Paul Cercueil wrote: >> >> >> >> >> >> Le lun. 1 avril 2019 à 19:17, Bin Liu <b-liu@ti.com> a écrit : >> >> >On Thu, Mar 21, 2019 at 03:42:46PM +0100, Paul Cercueil wrote: >> >> >> When the musb is shutdown, for instance when the driver is >> >>unloaded, >> >> >> force-disable the pullup. Otherwise, the host will still see >> >> >>the gadget >> >> >> device even after the shutdown. >> >> > >> >> >how would this happen? >> >> > >> >> >when musb-hdrc driver is unloaded, udc core removes the bound >> >>gadget >> >> >driver which calls musb_gadget_pullup() to disable the pullup. >> >> >> >> I'm testing with the jz4740-musb driver. I don't unload the >> >>module (it's >> >> built-in) but unbind it from sysfs. >> > >> >I did unbind too. >> > >> >root@am335x-evm:/sys/bus/platform/drivers/musb-hdrc# echo >> >musb-hdrc.0 > unbind >> > >> >or unbind the glue driver: >> > >> >root@am335x-evm:/sys/bus/platform/drivers/musb-dsps# echo >> >47401400.usb > unbind >> > >> >musb_gadget_pullup() is called in both cases. >> > >> >[ 3880.597014] [<bf444ab0>] (musb_gadget_pullup [musb_hdrc]) from >> >[<bf402cbc>] (usb_gadget_disconnect+0x3c/0xf4 [udc_core]) >> >[ 3880.607959] [<bf402cbc>] (usb_gadget_disconnect [udc_core]) >> >from [<bf403b28>] (usb_gadget_remove_driver+0x4c/0x90 [udc_core]) >> >[ 3880.619338] [<bf403b28>] (usb_gadget_remove_driver [udc_core]) >> >from [<bf403d20>] (usb_del_gadget_udc+0x5c/0xc0 [udc_core]) >> >> In my case this stops here, usb_del_gadget_udc() does not call >> usb_gadget_remove_driver(), that's why the pullup is never disabled. >> >> I guess that's because udc->driver is NULL; I'm testing with > > then the pullup should be disable by now. > >> CONFIG_USB_CONFIGFS, >> and I don't configure anything in sysfs before unbinding the driver. > > I didn't check on this, but I could imagine that > - when a configfs gadget is bound to the udc, .pullup() is called; > - when the configfs gadget is unbound from the udc, .pullup should be > called again to disable the pullup.
An important thing that I did not mention, is that the SoC boots from USB, so the pullup is active before the musb driver loads. Since in my case a configfs gadget is never bound, then .pullup() is never called, and when I unbind the driver the pullup is still enabled.
-Paul
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