From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vostrikov Andrey Subject: Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Date: Wed, 20 Jan 2016 23:09:39 +0300 Message-ID: <691920039.20160120230939@cogentembedded.com> References: <20150511013540.5709.93626.stgit@notabene.brown> <481E05A9-A192-438D-B092-D7700B30BBC4@goldelico.com> <20160113191542.GA12086@leverpostej> <1CD6CA14-AE4F-444F-A9A2-CF9B9485F2DC@goldelico.com> <20160115110106.GA3262@leverpostej> <69F8E1E5-EF49-4C8E-88E9-973F82F7102E@goldelico.com> <569913A1.80606@cogentembedded.com> <56992959.2020204@hurleysoftware.com> <744620565.20160116103445@cogentembedded.com> Reply-To: Vostrikov Andrey Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Dmitry Torokhov Cc: Rob Herring , Peter Hurley , "H. Nikolaus Schaller" , Mark Rutland , List for communicating with real GTA04 owners , Tomeu Vizoso , NeilBrown , One Thousand Gnomes , Arnd Bergmann , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Greg Kroah-Hartman , Sebastian Reichel , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Pavel Machek , "linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Grant Likely , Jiri Slaby , Marek Belisko List-Id: devicetree@vger.kernel.org Hi, Dmitry. > On Fri, Jan 15, 2016 at 11:34 PM, Vostrikov Andrey > wrote: >> >> Yes, such implementation will help. There is a need for interface like UART BUS that will probe devices without user space. >> Serial I/O for input subsystem defines new type of bus and uses dedicated line discipline, but it still unable to start driver by itself and requires call from 'inputattach' to open port, assign line discipline and go to forever wait on 'read'. > That was done mainly because almost none of the serial protocols could > be auto-probed, so device initialization/setup was moved out of kernel > and thus we have the separate line discipline and inputattach utility. This is understandable for "dummy" devices like mice, that only report input events. But in case there is "intellectual" MCU, that must reply on specific commands with specific response - it could be auto-probed. Especially when it is hardwired. Unfortunately, there is no API to do it. Opening port and attaching line discipline from kernel side does not look good. The only example is '/dev/console', which is implemented that way. > Thanks. -- Best regards, Andrey Vostrikov -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html