From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH 1/4] serial: 8250: Copy em485 from port to real port. Date: Wed, 06 Jun 2018 16:11:46 +0300 Message-ID: <2abe2137e699e5ae3100b97316da469f6d1c9bb9.camel@linux.intel.com> References: <20180606094942.71190-1-giulio.benetti@micronovasrl.com> <20180606094942.71190-4-giulio.benetti@micronovasrl.com> <069f5cd3309e83d13c74929f240720b232ea7251.camel@linux.intel.com> <0bc400b1-6178-2021-c9a3-3190d1a1de32@micronovasrl.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <0bc400b1-6178-2021-c9a3-3190d1a1de32@micronovasrl.com> Sender: linux-kernel-owner@vger.kernel.org To: Giulio Benetti Cc: matwey.kornilov@gmail.com, Greg Kroah-Hartman , Jiri Slaby , Matthias Brugger , Kees Cook , Allen Pais , Sean Young , "open list:SERIAL DRIVERS" , open list List-Id: linux-serial@vger.kernel.org On Wed, 2018-06-06 at 14:15 +0200, Giulio Benetti wrote: > Il 06/06/2018 13:56, Andy Shevchenko ha scritto: > > On Wed, 2018-06-06 at 11:49 +0200, Giulio Benetti wrote: > > > em485 gets lost during > > > > > > Copy em485 to final uart port. > > > > > > > Is it needed at all? > > > > The individual driver decides either to use software emulation (and > > calls explicitly serial8250_em485_init() for that) or do HW assisted > > stuff. > > In 8250_dw.c, during probe(), I need to call dw8250_rs485_config() > against local struct uart_8250_port uart = {}; > Inside serial8250_register_8250_port() not all uart fields are > copied(em485 too). > So after probe, em485 is NULL. > > Another way could be to call dw8250_rs485_config() against real uart > port, after calling serial8250_register_8250_port(), > would it make sense? Look at OMAP case closely. They have a callback to configure RS485 which is called in uart_set_rs485_config() which is called whenever user space does TIOCGRS485 IOCTL. So, it's completely driven by user space which makes sense by my opinion. -- Andy Shevchenko Intel Finland Oy