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bh=KUxpJqYYa0VhNofPWE55WEfT0pzSsC+tc3Iw1yJfJ80=; b=HKxugvqmlXpYp00MdUMi8LdjB/ut+8I3zFW6xoA9fpxouy34H7l4QeEH1BXYeBOE7FxOE9 NjQNxmrt6ulvJwxDl30gHKLWJVYbXabaScEloreVGrP+rikqz0/W84cCWMSgkEV6pEPH35 YSkiOVtvZQmbC5WBMXXMIgbrS71E0PZqMzeP+NCrWcFcX93tadIRVjAQ8A9tfIXM1jxKaI SuX6hqE52+3qO6W2bu5QjqYnXPsI0GwvUwtlbNS6AaqWB2b7Uy3ZgKjnQYUoT9jbq9quM1 lf/0rDB21QVeASXPQ/PTNk8FNmD5by4w2OLHa48KLXakvZE970v99pA5YSpuJg== From: Miquel Raynal To: Rob Herring Cc: Manikandan.M@microchip.com, krzk@kernel.org, pratyush@kernel.org, mwalle@kernel.org, takahiro.kuwano@infineon.com, richard@nod.at, vigneshr@ti.com, krzk+dt@kernel.org, conor+dt@kernel.org, srini@kernel.org, Nicolas.Ferre@microchip.com, alexandre.belloni@bootlin.com, claudiu.beznea@tuxon.dev, linux@armlinux.org.uk, richardcochran@gmail.com, linusw@kernel.org, arnd@arndb.de, michael@walle.cc, linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org Subject: Re: [PATCH v4 1/7] dt-bindings: mtd: jedec,spi-nor: allow the SFDP to be exposed via NVMEM In-Reply-To: <20260702163723.GA227454-robh@kernel.org> (Rob Herring's message of "Thu, 2 Jul 2026 11:37:23 -0500") References: <20260630092406.150587-1-manikandan.m@microchip.com> <20260630092406.150587-2-manikandan.m@microchip.com> <20260702-utopian-termite-of-perfection-f1f3ec@quoll> <860213fd-6a4b-42d4-a8f7-7308e070f09e@microchip.com> <20260702163723.GA227454-robh@kernel.org> User-Agent: mu4e 1.12.7; emacs 30.2 Date: Fri, 03 Jul 2026 12:10:32 +0200 Message-ID: <8733y0penb.fsf@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260703_031043_771897_7302CCFC X-CRM114-Status: GOOD ( 13.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 02/07/2026 at 11:37:23 -05, Rob Herring wrote: > On Thu, Jul 02, 2026 at 06:55:15AM +0000, Manikandan.M@microchip.com wrot= e: >> Hi Krzysztof, >>=20 >> On 7/2/26 11:46 AM, Krzysztof Kozlowski wrote: >> > EXTERNAL EMAIL: Do not click links or open attachments unless you know= the content is safe >> >=20 >> > On Tue, Jun 30, 2026 at 02:54:00PM +0530, Manikandan Muralidharan wrot= e: >> >> Add an optional "sfdp" child node (compatible "jedec,sfdp") that >> >> describes the SFDP as a read-only NVMEM provider via nvmem.yaml, so i= ts >> >=20 >> > What is SFDP? >> >=20 >> SFDP is the Serial Flash Discoverable Parameters -- a JEDEC-standardised >> (JESD216) read-only parameter table present in most SPI NOR flashes, the= =20 >> table contents provide basic information about the flash. There are=20 >> standard tables which are specified by the JEDEC standard and there are= =20 >> vendor tables. > > Is SFDP present or not discoverable? Or we have a table of discoverable=20 > parameters that itself is not discoverable. SFDP is almost always there. I don't think there are any non SFDP chips manufactured today (?). The thing is, even if we don't need to define it in DT, we might need to point to it in order to extract eg. a unique ID or a MAC address through the NVMEM interface. SFDP is split into several sub-tables, the first one is mandatory, but then there are optional tables which can be discovered dynamically. Thanks, Miqu=C3=A8l