From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1FEB0C433EF for ; Mon, 14 Feb 2022 16:19:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356265AbiBNQT1 (ORCPT ); Mon, 14 Feb 2022 11:19:27 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:60384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235279AbiBNQTZ (ORCPT ); Mon, 14 Feb 2022 11:19:25 -0500 X-Greylist: delayed 325 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 14 Feb 2022 08:19:16 PST Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BFC9142EE7; Mon, 14 Feb 2022 08:19:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1644855555; bh=uSiLH41ols2or+PlxwtXv6HH6qStx8ca3yFi6b4NLDA=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=ZC7ys4YhFML+XPJP4mpPLukOKwb3QxulUMHO1uX8Hq+HpNupjBq/FCaMNZWCyzOrC j4XAOTnkQ82dP5VK3x9FkaVwl9jvII4DfttWmiXFtUL3EXEeKXVKBdSWBH71mgYOo8 29J1VuwkZ/58p81/nn9SE5mDcQhIMg3Fxj+h3Vas= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [192.168.178.70] ([149.172.237.68]) by mail.gmx.net (mrgmx004 [212.227.17.190]) with ESMTPSA (Nemesis) id 1N4hzZ-1oK5ig2JyZ-011et8; Mon, 14 Feb 2022 17:13:21 +0100 Subject: Re: [PATCH 1/9] serial: core: move RS485 configuration tasks from drivers into core To: Jiri Slaby , gregkh@linuxfoundation.org Cc: linux@armlinux.org.uk, richard.genoud@gmail.com, nicolas.ferre@microchip.com, alexandre.belloni@bootlin.com, ludovic.desroches@microchip.com, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com, mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com, lukas@wunner.de References: <20220213222737.15709-1-LinoSanfilippo@gmx.de> <20220213222737.15709-2-LinoSanfilippo@gmx.de> From: Lino Sanfilippo Message-ID: <9791fb9a-0c27-bfeb-5ff8-fb70f1968048@gmx.de> Date: Mon, 14 Feb 2022 17:13:20 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:YBdfvrtYI85+zaH+ORjAj6/z8NhLNObYZSKxNdCEkYmHpFKgUBz cvg3dOdbbi7AbkXhFtpSGhjhlkoJcur1g466o350MRispTjbtggc/xvrNm0IEnPKTmC4Fkg ROY/D/pVATsNvg4nEopPdn+DX0L1U4hzKUnMq65l9KuxdLJPNytzgJQ4VZ54vUVWFPmvQlR C3w+lEE3o7q8OAa4qDaLQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:pSOpZ7x17Fc=:woJNeKPRbcarBQfg1Sp6p7 EZIgFKw/ObO5hG40inIuLkbDrW1Cy7/VwTqs4SL8vVgokDaexgmTkVpPcpfkMVgEGXaC+131K 4MOJ40qg77xhl/2+g7sROXl0Gpev4OgRHgi8d8TOCHryUcg0C+xeH3jJUQ4rsAMO43iFAwH8F 75Toj4COP0vB9E19Bwik9eh0ykb+6Kf4ASJttjlHCAXoe0XfAdyyBSunQKrlCAglRtZe9HzUK oi1hvv9ayePRgRydJopIP6VlkO4I548O+ARH7wjVq1nTcLYa/y6XJaepY4Xa785OyxBEeK97Q r4HO7QJ0NVzeQmMR/TaaMX5d+1SBy3p7iXyk+fGvAALLUQIEwGDmjC80me3wmv25Y09Thsd+P r3TDp5YYU5zxoH0fDwewDIB0NN00k/daykXSa5lZEryBsk7L2KFj6LavAYexzwxTtkfWzNJJk FbWUzMRTW1utAZqfn79VzUjdHp8CyChiPxrEvTxxkBaAXqgn5bWjXGSLe79ZnvHjtbdi/INY1 rFGKejQMMz7kUqwAYqTf2ZqwAyvKR8csmuMT7fcvk1NAvx7bFgXd6MQUIBrrumCAGpmMyfmvU aZz2Ly5EU7gSzjXoeKvKZEuqiTKRH63DGcBKlFEUIk3RaRoeW6oi6byeqAHBmR+iXwBcHbKu6 a/G9Hv63wvfuUBBDVJCwWQztHY7+uOg+KlLHzLqKfqoDXAVZfyuvWOJKiuAS+redDyvtLbQGB V2eXimZUERoDCGoFgvy2jkR0q2k2wg82foqSOhBQTbMvJVf4eMnPCSTTaO/c5b+HzflTN8VlF 24OW7D3XS9fDozKPj5Z3MYrX3GKAkiDzuEbp2vbXBndwDASH3mm0UVetIVI+g/39rI+UwN9YM GWJbDrnRsL3NKXXssaoqD8JtDdPk3F/jMtg8Naw8KEnJBfPmuHkZjIoptMzEymDsDpWZGZljI er4IGuIcrlknVgq173Hrr1C+2dX5woLtmBq7AXP3JnUfZs3Qowf4HQAWUPPEAkV/rJ7fTMs52 br0Rg8YOY1vLM1kQ58Gt+ffgs02crf7kRhTh2xwNgKGy3tnH4D2fPtXZsKNMQGm4LrkbAVBoH wngwmUzMkytIXs= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 14.02.22 at 06:41, Jiri Slaby wrote: > On 13. 02. 22, 23:27, Lino Sanfilippo wrote: >> Several drivers that support setting the RS485 configuration via usersp= ace >> implement on or more of the following tasks: >> >> - in case of an invalid RTS configuration (both RTS after send and RTS = on >> =C2=A0=C2=A0 send set or both unset) fall back to enable RTS on send an= d disable RTS >> =C2=A0=C2=A0 after send >> >> - nullify the padding field of the returned serial_rs485 struct >> >> - copy the configuration into the uart port struct >> >> - limit RTS delays to 100 ms >> >> Move these tasks into the serial core to make them generic and to provi= de >> a consistent beheviour among all drivers. >> >> Signed-off-by: Lino Sanfilippo >> --- >> =C2=A0 drivers/tty/serial/serial_core.c | 13 +++++++++++++ >> =C2=A0 1 file changed, 13 insertions(+) >> >> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/seri= al_core.c >> index 846192a7b4bf..3fab4070359c 100644 >> --- a/drivers/tty/serial/serial_core.c >> +++ b/drivers/tty/serial/serial_core.c >> @@ -1282,8 +1282,21 @@ static int uart_set_rs485_config(struct uart_por= t *port, >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (copy_from_user(&rs485, rs485_user, s= izeof(*rs485_user))) >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return -EFAULT; >> =C2=A0 +=C2=A0=C2=A0=C2=A0 /* pick sane settings if the user hasn't */ >> +=C2=A0=C2=A0=C2=A0 if (!(rs485.flags & SER_RS485_RTS_ON_SEND) =3D=3D >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 !(rs485.flags & SER_RS485_R= TS_AFTER_SEND)) { >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 rs485.flags |=3D SER_RS485_= RTS_ON_SEND; >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 rs485.flags &=3D ~SER_RS485= _RTS_AFTER_SEND; >> +=C2=A0=C2=A0=C2=A0 } >> +=C2=A0=C2=A0=C2=A0 /* clamp the delays to [0, 100ms] */ >> +=C2=A0=C2=A0=C2=A0 rs485.delay_rts_before_send =3D min(rs485.delay_rts= _before_send, 100U); >> +=C2=A0=C2=A0=C2=A0 rs485.delay_rts_after_send =3D min(rs485.delay_rts_= after_send, 100U); > > Why is this magic 100? The only drivers that seem to care about a max value for the RTS delays us= e 100 ms (omap-serial, amba pl011, 8250) so I chose this to stay compatible with th= e current driver implementations. 100 ms also seems large enough to be used as a gen= eral max value. > Can we have that number somehow documented? You should define a macro fo= r that anyway. Ok, I will do so. > >> +=C2=A0=C2=A0=C2=A0 memset(rs485.padding, 0, sizeof(rs485.padding)); > > What is this memset good for? Drivers like max310x, amba-pl011, 8250_pci, 8250_fintek, 8250_lpc18xx seem= to care about returning a serial_rs485 struct with cleared padding field to userspace. S= o they all clear that field on their own. Although not really necessary, to me this seems t= o be a good default behavior, so I added it to the serial core. > >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 spin_lock_irqsave(&port->lock, flags); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ret =3D port->rs485_config(port, &rs485)= ; >> +=C2=A0=C2=A0=C2=A0 if (!ret) >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 port->rs485 =3D rs485; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 spin_unlock_irqrestore(&port->lock, flag= s); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (ret) >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return ret; > > thanks, Thanks for the review! Regards, Lino