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 0CEC4C433F5 for ; Mon, 21 Feb 2022 08:48:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344083AbiBUIsg (ORCPT ); Mon, 21 Feb 2022 03:48:36 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:39852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231215AbiBUIsb (ORCPT ); Mon, 21 Feb 2022 03:48:31 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C2092BB for ; Mon, 21 Feb 2022 00:48:09 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C372260FF6 for ; Mon, 21 Feb 2022 08:48:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27A79C340E9; Mon, 21 Feb 2022 08:48:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645433288; bh=F9sqcLyspIX4pzjZ2h+Guk2EJ//c30PKHdsONCNhaYI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=L1aQk9rwgZ1kKxQJxv2uV6IZh31IxE3pzMwtt0NIFrqPt6gfq4U2+hnGtbUOjU7rU PIHdUFYBBVFecTZwmuZN2spctUA4kxYyfqs04h3AavsQLtwZPLzsIXNo8RBnsszy9t UFhdSUlujcR+76Ov/dlJu+wKeSBR7qY/5420uH955sWGsQ8jBiqp7+w1tAhj/QIENW eN9LmNG4JxTzziQH6DHPHGVrpXGGQdTUSHZiKP9RXJsSLVGLvqkdXSyqMBghGpG+bV DzlQtjAfoCP6NY5gkuOmlEIF7DvMxuBqchmpzv+A+uYm9kt5wJHEgGclmjjjbw4w9q ZFNZ3pt+oVbww== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1nM4MW-0003rn-OE; Mon, 21 Feb 2022 09:48:04 +0100 Date: Mon, 21 Feb 2022 09:48:04 +0100 From: Johan Hovold To: Dmytro Bagrii Cc: Jan-Niklas Burfeind , Greg KH , linux-usb@vger.kernel.org, Frank A Kingswood , Frank Zago Subject: Re: [PATCH] Revert "USB: serial: ch341: add new Product ID for CH341A" Message-ID: References: <20220207000822.697343-1-dimich.dmb@gmail.com> <6df2c9e6-8757-d5e4-0c27-d47f53bee2e1@gmail.com> <02efa491-39fe-e4f3-d617-a6f17ceba6a5@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <02efa491-39fe-e4f3-d617-a6f17ceba6a5@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Thu, Feb 10, 2022 at 07:41:22AM +0200, Dmytro Bagrii wrote: > On 09.02.22 16:18, Johan Hovold wrote: > > I don't remember all the details, but judging from a quick look it seems > > we're just waiting for someone to resend the revert with a proper > > explanation. > > > > It would be good if Jan-Niklas could chime in too and confirm if he's > > able to use the device in UART mode instead. > > I'd like to take a look at that keeyees device from original commit > message to see if it has EEPROM chip. I can hypothesize that some > manufacturer of a CH341-based programmer could use external configuration > EEPROM and mixed-up PID value. I haven't experiment with configuring > CH341A with EEPROM but suppose it's possible to burn any custom VID:PID > there. I don't think ch341 driver has to handle any of such custom > VID/PID, especially if it conflicts with an original VID/PID assigned by > chip manufacturer. In case of some peculiar devices it's possible to bind > custom VID:PID to the driver via sysfs. > > But it's just my hypothetical assumption how ch341-based device with PID > 5512 could work as UART in that case. > > I just checked if CH341 that i have can work as UART when configured as > I2C/SPI (PID 5512). I doesn't work: no output signal on TX pin, no > loopback echo when RX connected to self TX. Thanks for confirming. Johan