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dkim=none (message not signed) header.d=none;dmarc=fail action=none header.from=foss.st.com; Received-SPF: Fail (protection.outlook.com: domain of foss.st.com does not designate 164.130.1.59 as permitted sender) receiver=protection.outlook.com; client-ip=164.130.1.59; helo=smtpO365.st.com; Received: from smtpO365.st.com (164.130.1.59) by AM3PEPF0000A791.mail.protection.outlook.com (10.167.16.120) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9632.12 via Frontend Transport; Mon, 23 Feb 2026 14:24:46 +0000 Received: from STKDAG1NODE2.st.com (10.75.128.133) by smtpo365.st.com (10.250.44.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29; Mon, 23 Feb 2026 15:27:01 +0100 Received: from [10.48.87.127] (10.48.87.127) by STKDAG1NODE2.st.com (10.75.128.133) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29; Mon, 23 Feb 2026 15:24:45 +0100 Message-ID: Date: Mon, 23 Feb 2026 15:24:43 +0100 Precedence: bulk X-Mailing-List: imx@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 3/4] gpio: rpmsg: add generic rpmsg GPIO driver To: Linus Walleij , Shenwei Wang CC: Andrew Lunn , Bartosz Golaszewski , Jonathan Corbet , Rob Herring , "Krzysztof Kozlowski" , Conor Dooley , "Bjorn Andersson" , Mathieu Poirier , Frank Li , Sascha Hauer , Shuah Khan , "linux-gpio@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Pengutronix Kernel Team" , Fabio Estevam , "Peng Fan" , "devicetree@vger.kernel.org" , "linux-remoteproc@vger.kernel.org" , "imx@lists.linux.dev" , "linux-arm-kernel@lists.infradead.org" , dl-linux-imx , Bartosz Golaszewski References: <20260212213656.662437-1-shenwei.wang@nxp.com> <20260212213656.662437-4-shenwei.wang@nxp.com> <13f9d767-61d6-4e29-b36e-6dcc860ccb11@lunn.ch> <396819f2-dd00-4c09-8bc7-c035a5282a56@lunn.ch> Content-Language: en-US From: Arnaud POULIQUEN In-Reply-To: Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: ikV5BsX8SRIQc/UE8inwvpvw13u35cjAwxqTIkoM6AVKhOMXAuvsCKwkL5DnmbjJb68fmH6G5qqtYdxp+67BXAmsiQ3WoDrRz8exODpGGiWMiR9cm9dbkPvr8iA5d9Wd0MMz9YDkkYAM97RAhp0qsT5vtGp0NOzwyzKtFbPjT1x1XfaFl4l8RJXqtfEtWrA/QvaB+KuaGG+5mYkmFGXulrmiTgSEEgEOgn+gKmzM1+gdlWnjOu7+SUN2u7idLRwdGan8CaCRD/OUkxxXkvDxAWf/tuGZtAsEf7Hb3mPn0cdOc+pcmp/jyrQcFuotUX5lEJDDoZPJeay13QHbKiTkcoT6MZqAeXB6Ko4kM3SeNIGD9NbEZ3j3ObuEBNYEzvnrO1RrvmP+SYeyxQ8+MDz35yGT9TYMDk4uMWfkFHHymLtioq1vrdLnb29X/7icEenf X-OriginatorOrg: foss.st.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Feb 2026 14:24:46.5702 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: ca4d156f-e8e5-4c6a-35b6-08de72e74bb8 X-MS-Exchange-CrossTenant-Id: 75e027c9-20d5-47d5-b82f-77d7cd041e8f X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=75e027c9-20d5-47d5-b82f-77d7cd041e8f;Ip=[164.130.1.59];Helo=[smtpO365.st.com] X-MS-Exchange-CrossTenant-AuthSource: AM3PEPF0000A791.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: GV1PR10MB6516 Hello Linus, On 2/22/26 15:48, Linus Walleij wrote: > On Fri, Feb 20, 2026 at 7:57 PM Shenwei Wang wrote: > >> Given that, I’d like to hear from the GPIO subsystem maintainers — @Linus Walleij and >> @Bartosz Golaszewski — on whether a driver that works with the current hardware/firmware >> design could still be acceptable for upstream inclusion. My understanding is that upstream >> generally supports existing, real-world hardware as long as the driver meets subsystem standards. > > What a swell party this has become. > > In this kind of situations I usually refer to > Documentation/process/management-style.rst > Thank you for pointing out the document, I was not aware of its existence. Very informative! That help me to understand you proposal below. > What is the message I as a maintainer is getting from NXP regarding > "gpio: rpmsg: add generic rpmsg GPIO driver"? > > Arnaud, who is the only person in this discussion who actually wrote > a standard RPMSG driver (drivers/tty/rpmsg_tty.c), must ACK this > patch if it wants to call itself a "generic" RPMSG GPIO driver, if he > does not, then it isn't. In Fact there are already 2 "generic" drivers, the second one it the drivers/rpmsg/rpmsg_char.c, both are used on several platforms. It is in my plan to test the rpmsg-gpio on ST platform if we go with the generic approach. > > Is it generic? If it is not, let's call it "NXP rpmsg GPIO driver" and rename > files etc accordingly. Maybe it can share code with the actual generic > RPMSG driver once that arrives, that is more of a library question. I would like to (re)express my concerns regarding the creation of an NXP-specific driver. To clarify my concerns, ST, like probably some other SoC vendors, has rpmsg-gpio and rpmsg-i2c drivers in downstream with plans to upstream them. If we proceed in this direction: -Any vendor wishing to upstream an rpmsg-gpio driver might submit their own platform-specific version. - If NXP upstreams other rpmsg drivers, these will likely remain NXP-centric to maintain compatibility with their legacy firmware and the nxp-rpmsg-gpio driver, leading to platform-specific versions in several frameworks. - The implementation will impact not only the Linux side but also the remote side. Indeed, some operating systems like Zephyr or NuttX implement the rpmsg device side (Zephyr already implements the rpmsg-tty) Maintaining a generic approach for RPMsg, similar to what is done for Virtio, seems to me a more reliable solution, even though it may induce some downstream costs (ST would also need to break compatibility with legacy ST remote proc firmware). In the end, I am just trying to influence the direction for RPMsg, but based on the discussions in this thread, it seems others share similar expectations, which should probably be taken into account as well. Thanks and Regards, Arnaud I just want to > > Yours, > Linus Walleij