From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Jackson Subject: Re: [PATCH] Allow MUSB DSPS to use "force host" mode Date: Fri, 22 Nov 2013 17:07:46 +0000 Message-ID: <528F8F62.7000801@newflow.co.uk> References: <528F7E8F.5050807@newflow.co.uk> <528F8741.1060406@linutronix.de> <528F8B35.8070408@newflow.co.uk> <528F8DF1.2060307@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <528F8DF1.2060307@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org To: Sebastian Andrzej Siewior Cc: linux-usb@vger.kernel.org, lkml , Felipe Balbi , Greg KH , jkosina@suse.cz, anatol.pomozov@gmail.com, "linux-omap@vger.kernel.org" , Bin Liu List-Id: linux-omap@vger.kernel.org On 22/11/13 17:01, Sebastian Andrzej Siewior wrote: > On 11/22/2013 05:49 PM, Mark Jackson wrote: >>> and the ID pin not on ground or 3.3V? >>> What are the side effects? I remember correctly Bin wanted to avoid >>> settings this if it could be avoided. >> >> Yes ... we have a host only USB port and an unconnected ID pin. > > Is it too late to connect that pin? Unfortunately, yes. The USB portion of the CPU board has not been needed until now, and although I did know about the unconnected pin, I also knew it could be fixed in s/w, so I wasn't too concerned. >> AFAIK it defaults to device mode so I can't see any devices that get >> plugged into the USB port. >> >> If I tweak the s/w to "force" host mode on, then everything appears to >> work okay. >> >> I guess it's more of a hardware oversight that we left the pin floating >> but in the real world, I guess someone may want this feature to they >> can change the usb port type ? > > This is something I would prefer to avoid if possible. We have the > dr_mode attribute in DT. Based on that one we act as a device or host. > Now if you decide (via dr_mode) either for host or device that means we > have to set that bit. Where I feel a little uncomfortable is when > someone having OTG runs in hostmode and attaches a host. > >> >> Either way, I need to fix the current h/w (which can be done via s/w) >> hence the patch. > I've seen many projects where this pin has been forgotten and it could > not be changed in SW and they patched the HW. Usually this is noticed > in the early phase and a wire is just soldered and the redesign has it > fixed. So I don't think that this is a big issue. > Do you insists on having this change merged upstream? No ... I didn't think it would be such an issue, so I'm happy to keep this as a local patch if that's any better. Mark J.