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 89534C25B42 for ; Sat, 21 Oct 2023 17:03:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231794AbjJURCy (ORCPT ); Sat, 21 Oct 2023 13:02:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231782AbjJURCv (ORCPT ); Sat, 21 Oct 2023 13:02:51 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F2F6124; Sat, 21 Oct 2023 10:02:43 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BA79C433C8; Sat, 21 Oct 2023 17:02:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1697907762; bh=ZR0ckwmKzr4OchS2lwegZntLrbRhjuWKJprTwNRlhKA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=zzx55b4erPsj7YZNMNfFtL2EtmGTBx0Bp8qXeeztQVL8bzemR3zSoIF3OqMZBWbVy TKGFpCdKi1sb9UX1yXAEWGoFIdo7ftlaHaZahg/CvnyYEf6+MgJ73glavxb/S2a5Ug ZDAIJqhM9BGAtQ2ipnOOIME9F6CNOGlX9qsRlrfE= Date: Sat, 21 Oct 2023 19:02:40 +0200 From: Greg KH To: Frank Li Cc: alexandre.belloni@bootlin.com, conor.culhane@silvaco.com, imx@lists.linux.dev, jirislaby@kernel.org, joe@perches.com, linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, miquel.raynal@bootlin.com Subject: Re: [PATCH v2 1/1] tty: i3c: add TTY over I3C master support Message-ID: <2023102105-outfit-legroom-1633@gregkh> References: <20231020160027.3663772-1-Frank.Li@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231020160027.3663772-1-Frank.Li@nxp.com> Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Note, your subject line needs to change. On Fri, Oct 20, 2023 at 12:00:27PM -0400, Frank Li wrote: > In typical embedded Linux systems, UART consoles require at least two pins, > TX and RX. In scenarios where I2C/I3C devices like sensors or PMICs are > present, we can save these two pins by using this driver. Pins is crucial "Pins are crucial" > resources, especially in small chip packages. > > This introduces support for using the I3C bus to transfer console tty data, > effectively replacing the need for dedicated UART pins. This not only > conserves valuable pin resources but also facilitates testing of I3C's > advanced features, including early termination, in-band interrupt (IBI) > support, and the creation of more complex data patterns. Additionally, > it aids in identifying and addressing issues within the I3C controller > driver. But where is the serial data ending up at? Not a normal uart, what is on the other end? And do line settings mean anything here? > > Signed-off-by: Frank Li > --- > > Notes: > This patch depend on > https://lore.kernel.org/imx/20231018205929.3435110-1-Frank.Li@nxp.com/T/#t Let's wait for those to be accepted first, right? > +static DEFINE_IDR(i3c_tty_minors); > +static DEFINE_MUTEX(i3c_tty_minors_lock); I thought idr didn't need a mutex anymore, are you sure this is still needed? > +static struct tty_driver *i3c_tty_driver; > + > +#define I3C_TTY_MINORS 256 Do you really need 256 minors? > +#define I3C_TTY_TRANS_SIZE 16 > +#define I3C_TTY_RX_STOP 0 > +#define I3C_TTY_RETRY 20 > +#define I3C_TTY_YIELD_US 100 > + > +struct ttyi3c_port { > + struct tty_port port; > + int minor; > + spinlock_t xlock; /* protect xmit */ > + char tx_buff[I3C_TTY_TRANS_SIZE]; > + char rx_buff[I3C_TTY_TRANS_SIZE]; > + struct i3c_device *i3cdev; > + struct work_struct txwork; > + struct work_struct rxwork; > + struct completion txcomplete; > + unsigned long status; > + int buf_overrun; You set buf_overrun but never do anything with it. Why care about it? Other than these minor things, looks sane, nice work. thanks, greg k-h