From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753935AbeCUV5q (ORCPT ); Wed, 21 Mar 2018 17:57:46 -0400 Received: from muru.com ([72.249.23.125]:33096 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753816AbeCUV5h (ORCPT ); Wed, 21 Mar 2018 17:57:37 -0400 Date: Wed, 21 Mar 2018 14:57:33 -0700 From: Tony Lindgren To: Pavel Machek Cc: Sebastian Reichel , kernel list , linux-arm-kernel , linux-omap@vger.kernel.org, nekit1000@gmail.com, mpartap@gmx.net Subject: Re: 4.16-rc5 on Motorola Droid 4 Message-ID: <20180321215733.GE5799@atomide.com> References: <20180318220418.GA22880@amd> <20180320140322.GU5799@atomide.com> <20180320170029.rv3u5wlvqxfl7z2v@earth.universe> <20180321203137.GA23637@amd> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180321203137.GA23637@amd> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Pavel Machek [180321 20:32]: > Hi! > > > > Maybe get somebody to help you locally with the debug cable > > > soldering? :) > > > > I suppose people from your hackerspace can help you. It's really > > easy to do. Soldering can be avoided btw. You can just use a pair > > of scissors to cut a USB -> Micro USB cable and use a knife to remove > > isolation. Then screw each of the 4 wires into a terminal strip. > > There are USB-TTL adapters available, that have an attached cable. > > If you also cut the connector from such a cable and connect it to > > the other side of the terminal strip you are done. No soldering > > involved ;) > > Hm. How big no-no is connecting USB-TTL adapter to D+/D- pins? Because > that's what I could do "easily" and seems to work ;-). Well if the VBUS line is not connected the PMIC is muxed to USB carkit mode so the lines go to the UART on the SoC through some level shifter. If it works it should not cause any issues, the symptoms I saw earlier was corrupted UART console and noticed that what worked best for me was 3.3V ftdi based devices out of the collection of random pl2303 and ftdi cables I had around. I guess somebody could try to measure the uart lines with a scope with nothing connected and sending out data from droid 4. Or look at the carkit spec for the UART voltage levels. Regards, Tony