From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Chen Subject: Re: [PATCH v3 07/11] usb: otg: add OTG core Date: Mon, 20 Jul 2015 09:45:01 +0800 Message-ID: <20150720014500.GC4584@shlinux2> References: <1436350777-28056-1-git-send-email-rogerq@ti.com> <1436350777-28056-8-git-send-email-rogerq@ti.com> <20150717074832.GA4515@shlinux2> <55A8EFBA.1000504@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline In-Reply-To: <55A8EFBA.1000504@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: Roger Quadros Cc: Li Jun , stern@rowland.harvard.edu, balbi@ti.com, gregkh@linuxfoundation.org, dan.j.williams@intel.com, jun.li@freescale.com, mathias.nyman@linux.intel.com, tony@atomide.com, Joao.Pinto@synopsys.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org List-Id: linux-omap@vger.kernel.org On Fri, Jul 17, 2015 at 03:06:18PM +0300, Roger Quadros wrote: > >> + > >> +/** > >> + * OTG FSM ops function to start/stop host > >> + */ > >> +static int usb_otg_start_host(struct otg_fsm *fsm, int on) > >> +{ > >> + struct otg_data *otgd = container_of(fsm, struct otg_data, fsm); > >> + struct otg_hcd_ops *hcd_ops; > >> + > >> + dev_dbg(otgd->dev, "otg: %s %d\n", __func__, on); > >> + if (!fsm->otg->host) { > >> + WARN_ONCE(1, "otg: fsm running without host\n"); > >> + return 0; > >> + } > >> + > >> + if (on) { > >> + /* OTG device operations */ > >> + if (otgd->start_host) > >> + otgd->start_host(fsm, on); > >> + > >> + /* start host */ > >> + hcd_ops = otgd->primary_hcd.ops; > >> + hcd_ops->add(otgd->primary_hcd.hcd, otgd->primary_hcd.irqnum, > >> + otgd->primary_hcd.irqflags); > >> + if (otgd->shared_hcd.hcd) { > >> + hcd_ops = otgd->shared_hcd.ops; > >> + hcd_ops->add(otgd->shared_hcd.hcd, > >> + otgd->shared_hcd.irqnum, > >> + otgd->shared_hcd.irqflags); > >> + } > >> + } else { > >> + /* stop host */ > >> + if (otgd->shared_hcd.hcd) { > >> + hcd_ops = otgd->shared_hcd.ops; > >> + hcd_ops->remove(otgd->shared_hcd.hcd); > >> + } > >> + hcd_ops = otgd->primary_hcd.ops; > >> + hcd_ops->remove(otgd->primary_hcd.hcd); > >> + > >> + /* OTG device operations */ > >> + if (otgd->start_host) > >> + otgd->start_host(fsm, on); > >> + } > >> + > >> + return 0; > >> +} > > > > I do not see much benefit by this override function, usb_add/remove_hcd > > can be simply included by controller's start_host function, also there > > maybe some additional operations after usb_add_hcd, but this override > > function limit usb_add_hcd() is the last step. > > I had tried host start/stop way before but Alan's suggestion was to use > bind/unbind the host controller completely as that is much simpler > > [1] http://article.gmane.org/gmane.linux.usb.general/123842 > Jun may want we have some ways to override otg_fsm->ops by platform drivers, I think we all agree to call usb_add_hcd/usb_remove_hcd to start/stop host roles, just some platforms may need more than just call them. -- Best Regards, Peter Chen