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Tue, 22 Apr 2025 02:41:11 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ThreadId: Tb1fe2b3b8ab1c58e Date: Tue, 22 Apr 2025 08:40:51 +0200 From: "Arnd Bergmann" To: "Frieder Schrempf" , "Peng Fan" , "Pankaj Gupta" , linux-arm-kernel@lists.infradead.org, "Conor Dooley" , devicetree@vger.kernel.org, imx@lists.linux.dev, "Krzysztof Kozlowski" , linux-kernel@vger.kernel.org, "Rob Herring" , "Sascha Hauer" , "Shawn Guo" , "Srinivas Kandagatla" Cc: "Frieder Schrempf" , "Fabio Estevam" , "Frank Li" , "Geert Uytterhoeven" , "Greg Kroah-Hartman" , "Pengutronix Kernel Team" , =?UTF-8?Q?Rafa=C5=82_Mi=C5=82ecki?= , "Shengjiu Wang" , "Shenwei Wang" , "Xu Yang" , "Yoshihiro Shimoda" Message-Id: <6ee90a9e-cfa0-45f5-8036-bf04cb19db46@app.fastmail.com> In-Reply-To: <20250416142715.1042363-1-frieder@fris.de> References: <20250416142715.1042363-1-frieder@fris.de> Subject: Re: [RFC PATCH 0/5] Add NVMEM driver for i.MX93 OTP access through ELE Content-Type: text/plain Content-Transfer-Encoding: 7bit On Wed, Apr 16, 2025, at 16:26, Frieder Schrempf wrote: > Therefore I implemented a simple driver that uses the ELE S400 API only, as the > FSB access (1) doesn't provide any benefits except for that it doesn't depend > on the ELE firmware being available. This is used by us downstream. > > For the upstream solution I would like to have some feedback on how to move > on: > > 1. switch imx-ocotp-ele.c to use ELE API exclusively > -> this will create a hard dependency on the ELE firmware/driver > being available Could this cause problems for real-time Linux users? Usually going through a firmware driver adds more latency than doing the thing from Linux directly, and the firmware is usually not preemptable. In particular, programming a one-time fuse is likely a slow operation in hardware, so it may still be necessary to support both methods if there are users that need to update the fuses on real-time systems. Arnd