From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Chen Subject: Re: [PATCH v9 08/14] usb: otg: add OTG/dual-role core Date: Sun, 12 Jun 2016 14:26:17 +0800 Message-ID: <20160612062617.GC22054@shlinux2> References: <1465376626-30122-1-git-send-email-rogerq@ti.com> <1465376626-30122-9-git-send-email-rogerq@ti.com> <20160608095336.GA4444@shlinux2> <5757EF7A.20604@ti.com> <20160608124204.GB10029@shlinux2> <575919BC.8080003@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <575919BC.8080003-l0cyMroinI0@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Roger Quadros Cc: peter.chen-KZfg59tc24xl57MIdRCFDg@public.gmane.org, balbi-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, mathias.nyman-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, Joao.Pinto-HKixBCOQz3hWk0Htik3J/w@public.gmane.org, sergei.shtylyov-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org, jun.li-KZfg59tc24xl57MIdRCFDg@public.gmane.org, grygorii.strashko-l0cyMroinI0@public.gmane.org, yoshihiro.shimoda.uh-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org, robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, nsekhar-l0cyMroinI0@public.gmane.org, b-liu-l0cyMroinI0@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On Thu, Jun 09, 2016 at 10:24:44AM +0300, Roger Quadros wrote: > On 08/06/16 15:42, Peter Chen wrote: > > On Wed, Jun 08, 2016 at 01:12:10PM +0300, Roger Quadros wrote: > >> Hi, > >> > >> On 08/06/16 12:53, Peter Chen wrote: > >>> On Wed, Jun 08, 2016 at 12:03:40PM +0300, Roger Quadros wrote: > >>>> +int usb_otg_unregister(struct device *dev) > >>>> +{ > >>>> + struct usb_otg *otg; > >>>> + > >>>> + mutex_lock(&otg_list_mutex); > >>>> + otg = usb_otg_get_data(dev); > >>>> + if (!otg) { > >>>> + dev_err(dev, "otg: %s: device not in otg list\n", > >>>> + __func__); > >>>> + mutex_unlock(&otg_list_mutex); > >>>> + return -EINVAL; > >>>> + } > >>>> + > >>>> + /* prevent unregister till both host & gadget have unregistered */ > >>>> + if (otg->host || otg->gadget) { > >>>> + dev_err(dev, "otg: %s: host/gadget still registered\n", > >>>> + __func__); > >>> > >>> You need to call mutex_unlock here > >> > >> Indeed. good catch. > >>> > >>>> + > >>>> +int usb_otg_gadget_ready(struct usb_gadget *gadget, bool ready) > >>>> +{ > >>> > >>> What this API is for? Why need it in this version? > >> > >> we moved gadget to otg registration from udc_bind_to_driver() to usb_add_gadget_udc_release(). > >> This means there is a window when gadget function driver (e.g. g_zero) is not loaded. > >> We don't want to start the gadget controller in that window. > >> > >> usb_otg_gadget_ready() is used by gadget core to notify the otg core when the function driver > >> is ready or not-ready. > >> > > > > Why you need to move this from gadget's probe to udc's probe? Currently, > > the sequence of gadget and udc's probe is random, but udc_bind_to_driver > > is called when udc is ready. > > > Because we need to support -EPROBE_DEFER at udc probe. > At udc_bind_to_driver there is no scope for -EPROBE_DEFER. > Why udc_bind_to_driver can't return -EPROBE_DEFER if register to OTG is failed? > Another issue is that we need to register with otg and have otg->caps available > before driver->bind() is called in udc_bind_to_driver(). Else gadget function > will not have the correct OTG descriptor. > You can do register before calling driver->bind. -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html