From patchwork Tue May 31 04:37:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Mychaela N. Falconia" X-Patchwork-Id: 577768 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 DD5EBC433EF for ; Tue, 31 May 2022 04:37:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243846AbiEaEhM (ORCPT ); Tue, 31 May 2022 00:37:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240933AbiEaEhJ (ORCPT ); Tue, 31 May 2022 00:37:09 -0400 Received: from freecalypso.org (freecalypso.org [195.154.163.71]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D2AB522FB; Mon, 30 May 2022 21:37:08 -0700 (PDT) Received: by freecalypso.org (Postfix, from userid 1001) id 13427374023E; Tue, 31 May 2022 04:37:07 +0000 (UTC) From: "Mychaela N. Falconia" To: Johan Hovold , Greg Kroah-Hartman , Jiri Slaby Cc: linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, mychaela.falconia@gmail.com Subject: [PATCH v2 4/6] USB: serial: add sysfs attribute to suppress ready signalling on open In-Reply-To: <20220531043356.8CAB637401A9@freecalypso.org> References: <20220531043356.8CAB637401A9@freecalypso.org> Message-Id: <20220531043707.13427374023E@freecalypso.org> Date: Tue, 31 May 2022 04:37:06 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Johan Hovold Add a nordy sysfs attribute to suppress raising the modem-control lines on open to signal DTE readiness. This can be used to prevent undesirable side-effects on open for applications where the DTR and RTS lines are used for non-standard purposes such as generating power-on and reset pulses. Signed-off-by: Johan Hovold Signed-off-by: Mychaela N. Falconia --- drivers/usb/serial/bus.c | 35 +++++++++++++++++++++++++++++++++-- 1 file changed, 33 insertions(+), 2 deletions(-) diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c index 9e38142acd38..25f8218b2bce 100644 --- a/drivers/usb/serial/bus.c +++ b/drivers/usb/serial/bus.c @@ -29,6 +29,37 @@ static int usb_serial_device_match(struct device *dev, return 0; } +static ssize_t nordy_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct usb_serial_port *port = dev_get_drvdata(dev); + + return sprintf(buf, "%d\n", tty_port_nordy(&port->port)); +} + +static ssize_t nordy_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct usb_serial_port *port = dev_get_drvdata(dev); + bool val; + int ret; + + ret = kstrtobool(buf, &val); + if (ret) + return ret; + + tty_port_set_nordy(&port->port, val); + + return count; +} +static DEVICE_ATTR_RW(nordy); + +static struct attribute *tty_attrs[] = { + &dev_attr_nordy.attr, + NULL +}; +ATTRIBUTE_GROUPS(tty); + static int usb_serial_device_probe(struct device *dev) { struct usb_serial_port *port = to_usb_serial_port(dev); @@ -50,8 +81,8 @@ static int usb_serial_device_probe(struct device *dev) } minor = port->minor; - tty_dev = tty_port_register_device(&port->port, usb_serial_tty_driver, - minor, dev); + tty_dev = tty_port_register_device_attr(&port->port, + usb_serial_tty_driver, minor, dev, port, tty_groups); if (IS_ERR(tty_dev)) { retval = PTR_ERR(tty_dev); goto err_port_remove;