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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10306C433E0 for ; Tue, 9 Jun 2020 18:02:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE4E720734 for ; Tue, 9 Jun 2020 18:02:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591725726; bh=61wbgqZP6RiTlB2en8fs2oA+5228qjJ/z3HAiGnFn+A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UF59NHMYQefcRVLP6Elc9Pe54NSirEtvR2Y8YQ5emnBB/399M1BQfyB+tjA8hE+zl M7P2d+XWMfrruerKIKpdMYv2j9r/lAk7jcO4NS6NmH+cBq1Yjo2P+/g51ysnQEiYJF dfF2n5CWIWysWJ3VRVh0jHnKjsowbO3qmpNKGAMU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387837AbgFISCF (ORCPT ); Tue, 9 Jun 2020 14:02:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:45064 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731696AbgFIRxs (ORCPT ); Tue, 9 Jun 2020 13:53:48 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A926C20734; Tue, 9 Jun 2020 17:53:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591725228; bh=61wbgqZP6RiTlB2en8fs2oA+5228qjJ/z3HAiGnFn+A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BLpXqw6FgWG9zguQeLFPFMxGiubI9Ekaxza42YwjMI5++wa8JUAlGTkogbuNaURgq ZYWV37MuhKiDcLsT783n0TK6A3yyLM1FmQEEjU5NtxDge/tFCPK7TRNElmJLQbJg5A 6K0W++e7muZ7uuPdFuDxgbHJqnB5t9BHsNR52Tp4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Hanselmann , Johan Hovold Subject: [PATCH 5.6 21/41] USB: serial: ch341: add basis for quirk detection Date: Tue, 9 Jun 2020 19:45:23 +0200 Message-Id: <20200609174114.150309933@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200609174112.129412236@linuxfoundation.org> References: <20200609174112.129412236@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michael Hanselmann commit c404bf4aa9236cb4d1068e499ae42acf48a6ff97 upstream. A subset of CH341 devices does not support all features, namely the prescaler is limited to a reduced precision and there is no support for sending a RS232 break condition. This patch adds a detection function which will be extended to set quirk flags as they're implemented. The author's affected device has an imprint of "340" on the turquoise-colored plug, but not all such devices appear to be affected. Signed-off-by: Michael Hanselmann Link: https://lore.kernel.org/r/1e1ae0da6082bb528a44ef323d4e1d3733d38858.1585697281.git.public@hansmi.ch [ johan: use long type for quirks; rephrase and use port device for messages; handle short reads; set quirk flags directly in helper function ] Cc: stable # 5.5 Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/ch341.c | 53 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -87,6 +87,7 @@ struct ch341_private { u8 mcr; u8 msr; u8 lcr; + unsigned long quirks; }; static void ch341_set_termios(struct tty_struct *tty, @@ -308,6 +309,53 @@ out: kfree(buffer); return r; } +static int ch341_detect_quirks(struct usb_serial_port *port) +{ + struct ch341_private *priv = usb_get_serial_port_data(port); + struct usb_device *udev = port->serial->dev; + const unsigned int size = 2; + unsigned long quirks = 0; + char *buffer; + int r; + + buffer = kmalloc(size, GFP_KERNEL); + if (!buffer) + return -ENOMEM; + + /* + * A subset of CH34x devices does not support all features. The + * prescaler is limited and there is no support for sending a RS232 + * break condition. A read failure when trying to set up the latter is + * used to detect these devices. + */ + r = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), CH341_REQ_READ_REG, + USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, + CH341_REG_BREAK, 0, buffer, size, DEFAULT_TIMEOUT); + if (r == -EPIPE) { + dev_dbg(&port->dev, "break control not supported\n"); + r = 0; + goto out; + } + + if (r != size) { + if (r >= 0) + r = -EIO; + dev_err(&port->dev, "failed to read break control: %d\n", r); + goto out; + } + + r = 0; +out: + kfree(buffer); + + if (quirks) { + dev_dbg(&port->dev, "enabling quirk flags: 0x%02lx\n", quirks); + priv->quirks |= quirks; + } + + return r; +} + static int ch341_port_probe(struct usb_serial_port *port) { struct ch341_private *priv; @@ -330,6 +378,11 @@ static int ch341_port_probe(struct usb_s goto error; usb_set_serial_port_data(port, priv); + + r = ch341_detect_quirks(port); + if (r < 0) + goto error; + return 0; error: kfree(priv);