From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.3ffe.de (0001.3ffe.de [159.69.201.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8D0E31E5207; Fri, 3 Jul 2026 13:05:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.69.201.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783083930; cv=none; b=H4Xn5AoYPaQrSAAWwPYLs6CnAmzKJtQoPwDwqjx8VBBgGSDRRBQL3Hfo/YhLnW8SFz6rDUYYs+yr8zj88r2HUgbHbWf6pQf/qqu92EiqGuoqa3g+vLBIhEeT/FLWt6PQQBCKz3jk3aiaXOilPQqswYLbgFaEQyyIU/HjxwAVe1w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783083930; c=relaxed/simple; bh=pkRciNKbQ0ifl/vl6bLmmiWMxJohwsx+I+xkNEl8x9k=; h=Mime-Version:Content-Type:Date:Message-Id:Subject:Cc:From:To: References:In-Reply-To; b=s63VMeNIJFSJK/tbXW/+RZzXnhVfspjtt+DfqrrEfeO4YTruDYXhBlf3/dqApkKTD25FeQT8n6qpekwIjWnJKGUJ6eWY0J0W9UdjAXtiaTfi0BWs2ETYmrb+by1WJSPLV5fS4v4578550qlxXjLjQsxS883q4JvtazgeM/y6mms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=walle.cc; spf=pass smtp.mailfrom=walle.cc; dkim=pass (2048-bit key) header.d=walle.cc header.i=@walle.cc header.b=nbrNh1zR; arc=none smtp.client-ip=159.69.201.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=walle.cc Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=walle.cc Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=walle.cc header.i=@walle.cc header.b="nbrNh1zR" Received: from localhost (unknown [IPv6:2a02:810b:4320:1000:4685:ff:fe12:5967]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mail.3ffe.de (Postfix) with ESMTPSA id 08A4D4E2; Fri, 3 Jul 2026 15:05:20 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2022082101; t=1783083920; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OreQQ0XdKsQWlU/ho4QuvNgm2eEyh+R1RO2QdadtGn8=; b=nbrNh1zRQhB03C1yi+przXweH4RnERZffAT3vCSDaaxFgOrgAE3JWwxbVruloGmMtqMku6 T0AD0QKO85hwr06F2IJL9gKTBfGEYHPc9gCGM9BAbBkT9GLr6KFcq80FuRVMVlFY84ZJ01 /ZT59/9gw0hoskPrAhdBxSIlLd857e/7CKd0ZAYJ9GBaqAgTDBOp1pWkJR3y0eyVwj2C21 Wl+VrFYl3v7WRGDz8sjsns9LPSiqfPnjo2mf1c8lqxtacN2yZRDbCgvSHOFh1CVV6IH5ga XVRmYNWdAmYfOXvdAT8gY979h7ypsdOF0e3iWSproq2mdHOZqf/rcwxsygAS6A== Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Fri, 03 Jul 2026 15:05:19 +0200 Message-Id: Subject: Re: [PATCH v4 1/7] dt-bindings: mtd: jedec,spi-nor: allow the SFDP to be exposed via NVMEM Cc: , , , , , , , , , , , , , , , , , , , , , From: "Michael Walle" To: "Miquel Raynal" , "Rob Herring" X-Mailer: aerc 0.20.0 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> <8733y0penb.fsf@bootlin.com> In-Reply-To: <8733y0penb.fsf@bootlin.com> On Fri Jul 3, 2026 at 12:10 PM CEST, Miquel Raynal wrote: > 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 wro= te: >>> Hi Krzysztof, >>>=20 >>> On 7/2/26 11:46 AM, Krzysztof Kozlowski wrote: >>> > EXTERNAL EMAIL: Do not click links or open attachments unless you kno= w the content is safe >>> >=20 >>> > On Tue, Jun 30, 2026 at 02:54:00PM +0530, Manikandan Muralidharan wro= te: >>> >> Add an optional "sfdp" child node (compatible "jedec,sfdp") that >>> >> describes the SFDP as a read-only NVMEM provider via nvmem.yaml, so = its >>> >=20 >>> > What is SFDP? >>> >=20 >>> SFDP is the Serial Flash Discoverable Parameters -- a JEDEC-standardise= d >>> (JESD216) read-only parameter table present in most SPI NOR flashes, th= e=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 (?). Oh i bet there are, and IIRC there were some additions lately. Not sure if the chip was new though. > 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. Exactly. We can detect whether is a SFDP table or not, by trying to read its signature using the RDSFDP opcode. But as Miquel pointed out, that's not what this is about. For the nvmem part being useful, we have to have some node to point to. At the moment, there are three different kind of NVMEM devices an spi nor flash can create: - partitions - factory OTP (i.e. OTP by the flash manufacturer) - user OTP (i.e. what an OEM could write to) Now there's a fourth one: SFDP. It can contain vendor specific tables, which in the mchp case is used to store a mac address, which is then used for a NIC. So we somehow has to organize all of them, thus the sfdp node. A more complete example would be: flash@0 { compatible =3D "jedec,spi-nor"; partitions { compatible =3D "fixed-partitions"; partition@0 { compatible =3D "nvmem-cells"; }; }; otp-1 { compatible =3D "factory-otp"; }; otp-2 { compatible =3D "user-otp"; }; sfdp { compatile =3D "jedec,sfdp"; }; }; All being NVMEM devices and expose some kind of data used for drivers. HTH -michael > 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 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F1E06C43458 for ; Fri, 3 Jul 2026 13:05:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:References:To:From:Cc: Subject:Message-Id:Date:Mime-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; 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Fri, 3 Jul 2026 15:05:20 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2022082101; t=1783083920; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OreQQ0XdKsQWlU/ho4QuvNgm2eEyh+R1RO2QdadtGn8=; b=nbrNh1zRQhB03C1yi+przXweH4RnERZffAT3vCSDaaxFgOrgAE3JWwxbVruloGmMtqMku6 T0AD0QKO85hwr06F2IJL9gKTBfGEYHPc9gCGM9BAbBkT9GLr6KFcq80FuRVMVlFY84ZJ01 /ZT59/9gw0hoskPrAhdBxSIlLd857e/7CKd0ZAYJ9GBaqAgTDBOp1pWkJR3y0eyVwj2C21 Wl+VrFYl3v7WRGDz8sjsns9LPSiqfPnjo2mf1c8lqxtacN2yZRDbCgvSHOFh1CVV6IH5ga XVRmYNWdAmYfOXvdAT8gY979h7ypsdOF0e3iWSproq2mdHOZqf/rcwxsygAS6A== Mime-Version: 1.0 Date: Fri, 03 Jul 2026 15:05:19 +0200 Message-Id: Subject: Re: [PATCH v4 1/7] dt-bindings: mtd: jedec,spi-nor: allow the SFDP to be exposed via NVMEM Cc: , , , , , , , , , , , , , , , , , , , , , From: "Michael Walle" To: "Miquel Raynal" , "Rob Herring" X-Mailer: aerc 0.20.0 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> <8733y0penb.fsf@bootlin.com> In-Reply-To: <8733y0penb.fsf@bootlin.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260703_060532_126656_08083FDD X-CRM114-Status: GOOD ( 20.14 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org T24gRnJpIEp1bCAzLCAyMDI2IGF0IDEyOjEwIFBNIENFU1QsIE1pcXVlbCBSYXluYWwgd3JvdGU6 Cj4gT24gMDIvMDcvMjAyNiBhdCAxMTozNzoyMyAtMDUsIFJvYiBIZXJyaW5nIDxyb2JoQGtlcm5l bC5vcmc+IHdyb3RlOgo+Cj4+IE9uIFRodSwgSnVsIDAyLCAyMDI2IGF0IDA2OjU1OjE1QU0gKzAw MDAsIE1hbmlrYW5kYW4uTUBtaWNyb2NoaXAuY29tIHdyb3RlOgo+Pj4gSGkgS3J6eXN6dG9mLAo+ Pj4gCj4+PiBPbiA3LzIvMjYgMTE6NDYgQU0sIEtyenlzenRvZiBLb3psb3dza2kgd3JvdGU6Cj4+ PiA+IEVYVEVSTkFMIEVNQUlMOiBEbyBub3QgY2xpY2sgbGlua3Mgb3Igb3BlbiBhdHRhY2htZW50 cyB1bmxlc3MgeW91IGtub3cgdGhlIGNvbnRlbnQgaXMgc2FmZQo+Pj4gPiAKPj4+ID4gT24gVHVl LCBKdW4gMzAsIDIwMjYgYXQgMDI6NTQ6MDBQTSArMDUzMCwgTWFuaWthbmRhbiBNdXJhbGlkaGFy YW4gd3JvdGU6Cj4+PiA+PiBBZGQgYW4gb3B0aW9uYWwgInNmZHAiIGNoaWxkIG5vZGUgKGNvbXBh dGlibGUgImplZGVjLHNmZHAiKSB0aGF0Cj4+PiA+PiBkZXNjcmliZXMgdGhlIFNGRFAgYXMgYSBy ZWFkLW9ubHkgTlZNRU0gcHJvdmlkZXIgdmlhIG52bWVtLnlhbWwsIHNvIGl0cwo+Pj4gPiAKPj4+ ID4gV2hhdCBpcyBTRkRQPwo+Pj4gPiAKPj4+IFNGRFAgaXMgdGhlIFNlcmlhbCBGbGFzaCBEaXNj b3ZlcmFibGUgUGFyYW1ldGVycyAtLSBhIEpFREVDLXN0YW5kYXJkaXNlZAo+Pj4gKEpFU0QyMTYp IHJlYWQtb25seSBwYXJhbWV0ZXIgdGFibGUgcHJlc2VudCBpbiBtb3N0IFNQSSBOT1IgZmxhc2hl cywgdGhlIAo+Pj4gdGFibGUgY29udGVudHMgcHJvdmlkZSBiYXNpYyBpbmZvcm1hdGlvbiBhYm91 dCB0aGUgZmxhc2guIFRoZXJlIGFyZSAKPj4+IHN0YW5kYXJkIHRhYmxlcyB3aGljaCBhcmUgc3Bl Y2lmaWVkIGJ5IHRoZSBKRURFQyBzdGFuZGFyZCBhbmQgdGhlcmUgYXJlIAo+Pj4gdmVuZG9yIHRh Ymxlcy4KPj4KPj4gSXMgU0ZEUCBwcmVzZW50IG9yIG5vdCBkaXNjb3ZlcmFibGU/IE9yIHdlIGhh dmUgYSB0YWJsZSBvZiBkaXNjb3ZlcmFibGUgCj4+IHBhcmFtZXRlcnMgdGhhdCBpdHNlbGYgaXMg bm90IGRpc2NvdmVyYWJsZS4KPgo+IFNGRFAgaXMgYWxtb3N0IGFsd2F5cyB0aGVyZS4gSSBkb24n dCB0aGluayB0aGVyZSBhcmUgYW55IG5vbiBTRkRQIGNoaXBzCj4gbWFudWZhY3R1cmVkIHRvZGF5 ICg/KS4KCk9oIGkgYmV0IHRoZXJlIGFyZSwgYW5kIElJUkMgdGhlcmUgd2VyZSBzb21lIGFkZGl0 aW9ucyBsYXRlbHkuIE5vdApzdXJlIGlmIHRoZSBjaGlwIHdhcyBuZXcgdGhvdWdoLgoKPiBUaGUg dGhpbmcgaXMsIGV2ZW4gaWYgd2UgZG9uJ3QgbmVlZCB0byBkZWZpbmUgaXQKPiBpbiBEVCwgd2Ug bWlnaHQgbmVlZCB0byBwb2ludCB0byBpdCBpbiBvcmRlciB0byBleHRyYWN0IGVnLiBhIHVuaXF1 ZSBJRAo+IG9yIGEgTUFDIGFkZHJlc3MgdGhyb3VnaCB0aGUgTlZNRU0gaW50ZXJmYWNlLgoKRXhh Y3RseS4gV2UgY2FuIGRldGVjdCB3aGV0aGVyIGlzIGEgU0ZEUCB0YWJsZSBvciBub3QsIGJ5IHRy eWluZyB0bwpyZWFkIGl0cyBzaWduYXR1cmUgdXNpbmcgdGhlIFJEU0ZEUCBvcGNvZGUuIEJ1dCBh cyBNaXF1ZWwgcG9pbnRlZApvdXQsIHRoYXQncyBub3Qgd2hhdCB0aGlzIGlzIGFib3V0LiBGb3Ig dGhlIG52bWVtIHBhcnQgYmVpbmcgdXNlZnVsLAp3ZSBoYXZlIHRvIGhhdmUgc29tZSBub2RlIHRv IHBvaW50IHRvLiBBdCB0aGUgbW9tZW50LCB0aGVyZSBhcmUKdGhyZWUgZGlmZmVyZW50IGtpbmQg b2YgTlZNRU0gZGV2aWNlcyBhbiBzcGkgbm9yIGZsYXNoIGNhbiBjcmVhdGU6CiAtIHBhcnRpdGlv bnMKIC0gZmFjdG9yeSBPVFAgKGkuZS4gT1RQIGJ5IHRoZSBmbGFzaCBtYW51ZmFjdHVyZXIpCiAt IHVzZXIgT1RQIChpLmUuIHdoYXQgYW4gT0VNIGNvdWxkIHdyaXRlIHRvKQoKTm93IHRoZXJlJ3Mg YSBmb3VydGggb25lOiBTRkRQLiBJdCBjYW4gY29udGFpbiB2ZW5kb3Igc3BlY2lmaWMKdGFibGVz LCB3aGljaCBpbiB0aGUgbWNocCBjYXNlIGlzIHVzZWQgdG8gc3RvcmUgYSBtYWMgYWRkcmVzcywK d2hpY2ggaXMgdGhlbiB1c2VkIGZvciBhIE5JQy4KClNvIHdlIHNvbWVob3cgaGFzIHRvIG9yZ2Fu aXplIGFsbCBvZiB0aGVtLCB0aHVzIHRoZSBzZmRwIG5vZGUuIEEKbW9yZSBjb21wbGV0ZSBleGFt cGxlIHdvdWxkIGJlOgoKZmxhc2hAMCB7Cgljb21wYXRpYmxlID0gImplZGVjLHNwaS1ub3IiOwoK CXBhcnRpdGlvbnMgewoJCWNvbXBhdGlibGUgPSAiZml4ZWQtcGFydGl0aW9ucyI7CgoJCXBhcnRp dGlvbkAwIHsKCQkJY29tcGF0aWJsZSA9ICJudm1lbS1jZWxscyI7CgkJfTsKCX07CgoJb3RwLTEg ewoJCWNvbXBhdGlibGUgPSAiZmFjdG9yeS1vdHAiOwoJfTsKCglvdHAtMiB7CgkJY29tcGF0aWJs ZSA9ICJ1c2VyLW90cCI7Cgl9OwoKCXNmZHAgewoJCWNvbXBhdGlsZSA9ICJqZWRlYyxzZmRwIjsK CX07Cn07CgpBbGwgYmVpbmcgTlZNRU0gZGV2aWNlcyBhbmQgZXhwb3NlIHNvbWUga2luZCBvZiBk YXRhIHVzZWQgZm9yCmRyaXZlcnMuCgpIVEgKLW1pY2hhZWwKCj4gU0ZEUCBpcyBzcGxpdCBpbnRv IHNldmVyYWwgc3ViLXRhYmxlcywgdGhlIGZpcnN0IG9uZSBpcyBtYW5kYXRvcnksIGJ1dAo+IHRo ZW4gdGhlcmUgYXJlIG9wdGlvbmFsIHRhYmxlcyB3aGljaCBjYW4gYmUgZGlzY292ZXJlZCBkeW5h bWljYWxseS4KPgo+IFRoYW5rcywKPiBNaXF1w6hsCgoKX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCkxpbnV4IE1URCBkaXNjdXNzaW9uIG1haWxp bmcgbGlzdApodHRwOi8vbGlzdHMuaW5mcmFkZWFkLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4 LW10ZC8K