From mboxrd@z Thu Jan 1 00:00:00 1970 From: "gregkh@linuxfoundation.org" Subject: Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234 Date: Wed, 7 Aug 2019 18:56:46 +0200 Message-ID: <20190807165646.GA6584@kroah.com> References: <20190802194702.30249-1-stefan-gabriel.mirea@nxp.com> <20190802194702.30249-6-stefan-gabriel.mirea@nxp.com> <20190805153114.GA16836@kroah.com> <20190806184042.GA26041@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Stefan-gabriel Mirea Cc: "corbet@lwn.net" , "robh+dt@kernel.org" , "mark.rutland@arm.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "shawnguo@kernel.org" , Leo Li , "jslaby@suse.com" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-serial@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Cosmin Stefan Stoica , Larisa Ileana Grigore List-Id: linux-serial@vger.kernel.org On Wed, Aug 07, 2019 at 04:42:17PM +0000, Stefan-gabriel Mirea wrote: > On 8/6/2019 9:40 PM, gregkh@linuxfoundation.org wrote: > > On Tue, Aug 06, 2019 at 05:11:17PM +0000, Stefan-gabriel Mirea wrote: > >> On 8/5/2019 6:31 PM, gregkh@linuxfoundation.org wrote: > >>> On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote: > >>>> > >>>> +/* Freescale Linflex UART */ > >>>> +#define PORT_LINFLEXUART 121 > >>> > >>> Do you really need this modified? > >> > >> Hello Greg, > >> > >> This macro is meant to be assigned to port->type in the config_port > >> method from uart_ops, in order for verify_port to know if the received > >> serial_struct structure was really targeted for a LINFlex port. It > >> needs to be defined outside, to avoid "collisions" with other drivers. > > > > Yes, I know what it goes to, but does anyone in userspace actually use > > it? > > No, we do not use it from userspace, but kept the pattern only for > conformance. > > >> Other than that, I do not see anything wrong with the addition of a > >> define in serial_core.h for this purpose (which is also what most of the > >> serial drivers do, including amba-pl011.c, mentioned in > >> Documentation/driver-api/serial/driver.rst as providing the reference > >> implementation), so please be more specific. > > > > I am getting tired of dealing with merge issues with that list, and no > > one seems to be able to find where they are really needed for userspace, > > especially for new devices. What happens if you do not have use it? > > I see. If I drop its usage completely and leave 'type' from the > uart_port as 0, uart_port_startup() will fail when finding that > uport->type == PORT_UNKNOWN at [1] (there may be other effects as well, > e.g. due to the check in uart_configure_port[2]). > > So I suppose that I need to define some nonzero 'PORT_KNOWN' macro in > the driver and use that one internally for 'type'. Is my understanding > correct? Will there be any problems if I define it to a positive integer > which is already assigned to another driver, according to serial_core.h? Ugh, ok, that's messy, nevermind. Keep the #define in there, I will try to figure out how to move all of these at once sometime in the future... sorry for the noise. greg k-h