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 3E458C4332F for ; Wed, 1 Nov 2023 06:50:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231261AbjKAGuC (ORCPT ); Wed, 1 Nov 2023 02:50:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231240AbjKAGuC (ORCPT ); Wed, 1 Nov 2023 02:50:02 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9EA35A6; Tue, 31 Oct 2023 23:49:56 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5249C433C8; Wed, 1 Nov 2023 06:49:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698821396; bh=IrJZzwa1LgUljgZ2pNJ6BxSyMe71q3iklIBfrKxqK5g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=zz4teDGVyicLH+2JW0PTJ/4ys7ufZO5iW4ESyOqVpIzH++E1HRi7nYG3N+BJCa6ja sWDNEPGZ6CyFu0VTP3itptGAxbgW+oGvrnMTZSmA38HcsW6ND8od9LDYmCznkCNNSB pvWFb3+LKGTKPu2DkztOkcBPwFeWrgQHjxLfTOyA= Date: Wed, 1 Nov 2023 07:49:48 +0100 From: Greg Kroah-Hartman To: Crescent CY Hsieh Cc: Jiri Slaby , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org Subject: Re: [PATCH v2] tty: serial: Add RS422 flag to struct serial_rs485 Message-ID: <2023110127-wireless-candy-c298@gregkh> References: <20231101064404.45711-1-crescentcy.hsieh@moxa.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231101064404.45711-1-crescentcy.hsieh@moxa.com> Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Wed, Nov 01, 2023 at 02:44:04PM +0800, Crescent CY Hsieh wrote: > Add "SER_RS422_ENABLED" flag within struct serial_rs485, so that serial > port can switching interface into RS422 if supported by using ioctl > command "TIOCSRS485". > > In case of interfaces confliction, add checks within > uart_sanitize_serial_rs485() such that only one of RS422/RS485 is set. > > Signed-off-by: Crescent CY Hsieh > > --- > Changes in v2: > - Revise the logic that checks whether RS422/RS485 are enabled > simultaneously. > > v1: https://lore.kernel.org/all/20231030053632.5109-1-crescentcy.hsieh@moxa.com/ > > --- > drivers/tty/serial/serial_core.c | 19 +++++++++++++++++-- > include/uapi/linux/serial.h | 4 ++++ > 2 files changed, 21 insertions(+), 2 deletions(-) > > diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c > index 831d03361..54a104c52 100644 > --- a/drivers/tty/serial/serial_core.c > +++ b/drivers/tty/serial/serial_core.c > @@ -1305,7 +1305,7 @@ static int uart_get_icount(struct tty_struct *tty, > > #define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \ > SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \ > - SER_RS485_TERMINATE_BUS) > + SER_RS485_TERMINATE_BUS | SER_RS422_ENABLED) A new flag is "legacy"? > > static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485) > { > @@ -1371,11 +1371,26 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4 > { > u32 supported_flags = port->rs485_supported.flags; > > - if (!(rs485->flags & SER_RS485_ENABLED)) { > + if (!(rs485->flags & (SER_RS485_ENABLED | SER_RS422_ENABLED))) { > memset(rs485, 0, sizeof(*rs485)); > return; > } > > + /* Pick sane setting if the user enables both interfaces */ > + if (rs485->flags & SER_RS485_ENABLED && rs485->flags & SER_RS422_ENABLED) { > + dev_warn_ratelimited(port->dev, > + "%s (%d): Invalid serial interface setting, using RS485 instead\n", > + port->name, port->line); Why is this ratelimited? What would cause lots of repeats of this? > + rs485->flags &= ~SER_RS422_ENABLED; > + } > + > + /* Clear other bits and return if RS422 is enabled */ > + if (rs485->flags & SER_RS422_ENABLED) { > + memset(rs485, 0, sizeof(*rs485)); > + rs485->flags |= SER_RS422_ENABLED; > + return; > + } > + > /* Pick sane settings if the user hasn't */ > if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) && > !(rs485->flags & SER_RS485_RTS_ON_SEND) == > diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h > index 53bc1af67..427609fd5 100644 > --- a/include/uapi/linux/serial.h > +++ b/include/uapi/linux/serial.h > @@ -137,6 +137,8 @@ struct serial_icounter_struct { > * * %SER_RS485_ADDRB - Enable RS485 addressing mode. > * * %SER_RS485_ADDR_RECV - Receive address filter (enables @addr_recv). Requires %SER_RS485_ADDRB. > * * %SER_RS485_ADDR_DEST - Destination address (enables @addr_dest). Requires %SER_RS485_ADDRB. > + * > + * * %SER_RS422_ENABLED - RS422 enabled. > */ > struct serial_rs485 { > __u32 flags; > @@ -149,6 +151,8 @@ struct serial_rs485 { > #define SER_RS485_ADDR_RECV (1 << 7) > #define SER_RS485_ADDR_DEST (1 << 8) > > +#define SER_RS422_ENABLED (1 << 9) Why the extra blank line before this? And why isn't it using the proper BIT() type macro instead (yeah, the others are not, I understand...) Also, what userspace code is going to use this? How is it tested? thanks, greg k-h