From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.tq-group.com (mx1.tq-group.com [93.104.207.81]) (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 071A8168C3A; Fri, 21 Jun 2024 07:49:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.104.207.81 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718956147; cv=none; b=flDdB5tnbRIgY4GkhX9J8QMtVKQ9Bl90xw43IVKtjr2pI7wHPh00JWOiBjLYMWq6iRVwsEZVpAVRmfdx0SoNUeyGUOH/2OISZOTUJ1LWB+DWTzOkrTGZYDm79KW1qBMJ17ADe7DkbSgtMWBzBCCtsUxQWa/sit7U+RhVIKUWs3I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718956147; c=relaxed/simple; bh=wIlmEkajVgionahbTspK538zjM57VKi+YSPROMBtrCM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Q5AwTCeo8jcKRq++lXckAeNBb0R3ollWizFBpWCNxhafWw4aFFpdHANTH/7S5Um+e+Rm1uvJurQSTQmM3San68dLmgDs8Fvopfj30nvb0UM7zfRf1U2uagBYP4Wm2+II4SpswsV1DiAiVikkiJp8uvhb69WZQCGZH6kkteEuk3E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ew.tq-group.com; spf=pass smtp.mailfrom=ew.tq-group.com; dkim=pass (2048-bit key) header.d=tq-group.com header.i=@tq-group.com header.b=DBlbpCdB; dkim=fail (0-bit key) header.d=ew.tq-group.com header.i=@ew.tq-group.com header.b=mgMFAjs5 reason="key not found in DNS"; arc=none smtp.client-ip=93.104.207.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ew.tq-group.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ew.tq-group.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=tq-group.com header.i=@tq-group.com header.b="DBlbpCdB"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=ew.tq-group.com header.i=@ew.tq-group.com header.b="mgMFAjs5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1718956143; x=1750492143; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=wIlmEkajVgionahbTspK538zjM57VKi+YSPROMBtrCM=; b=DBlbpCdBlgvg89nMtcbkjg2pf3QGeUKROKke80Dv0mLdVSedaFVhuxUl Xqkp10yan6dKajxkbGlhm9/rupsF7Y4vt3m8F2/rwxkydR0ryIt9NAr+z WaRfCGgvFKw+jeWbGwC/oqd5lGO3zlTaEB4xa/ZIIB+QfYEszmaotfyM6 rPAv72Aygro5Io7zJ4gsbrAQUvdc5EGvnT0Pj49R7Ecaq/lW45xVuGZEJ vFg2CErI4QLuXOB/JsJDDcP5+lyUK0OOTxEVQeBQhu0RO0fL5H3tlqKUg 1qjHSm7zmAC4iP4rv0P404O33LJm4lr79tt2ygbA0EsBcGvP1uEZ+ZCEx A==; X-CSE-ConnectionGUID: s8GHXRv/SRCOEcMmDwWgyg== X-CSE-MsgGUID: SQUcTY4bRNqbIS5VTrS2oA== X-IronPort-AV: E=Sophos;i="6.08,254,1712613600"; d="scan'208";a="37515205" Received: from vmailcow01.tq-net.de ([10.150.86.48]) by mx1.tq-group.com with ESMTP; 21 Jun 2024 09:48:59 +0200 Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id A9407160A30; Fri, 21 Jun 2024 09:48:53 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ew.tq-group.com; s=dkim; t=1718956135; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=wIlmEkajVgionahbTspK538zjM57VKi+YSPROMBtrCM=; b=mgMFAjs5PkqL7DA5WhALlYJLzMWua/S6uYkLRX1dtyDPUUkdkChkAN/ZLy6tAht+56Giwf IGikV/5Kopjj4czSVeOmOznPBmfGgwxS4nYkeHknIukwuWOedcpGgY9KQEa1ZbWFwWhTC5 gFn+wfN5MCD6bSU5fKCYXGlXJ3dvQKPN9SubqLy/1xGp0nbxL6p/5KJAP+jzhzdoeWToks 19nxDRcY/soKwOhotRxhwLVtNwKA25I0wEVoPTKsSH7tlezsVdYjidK76xZjl3wr6WHq79 LrteIRg4wvOAyXyFaI9PJ9PWASzeGFVBHormvE2TWHDozerE1Ep5AWGNOdONKg== From: Alexander Stein To: Tudor Ambarus , Pratyush Yadav , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Michael Walle , Thorsten Scherer Cc: linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Marek Vasut , Imre Kaloz , Andrew Lunn , Flavio Suligoi Subject: Re: [PATCH] dt-bindings: mtd: spi-nor: deprecate Everspin MRAM devices Date: Fri, 21 Jun 2024 09:48:56 +0200 Message-ID: <114624730.nniJfEyVGO@steina-w> Organization: TQ-Systems GmbH In-Reply-To: References: <20240604074231.1874972-1-mwalle@kernel.org> <23574950.6Emhk5qWAg@steina-w> 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="iso-8859-1" X-Last-TLS-Session-Version: TLSv1.3 Hi, removing Uwe from CC as this address bounces. Am Freitag, 21. Juni 2024, 09:09:56 CEST schrieb Michael Walle: > On Fri Jun 21, 2024 at 8:49 AM CEST, Alexander Stein wrote: > > Hi everyone, > > > > sorry for being late to the party. I just noticed this discussion while > > reading [1]. > > > > Am Dienstag, 4. Juni 2024, 09:42:31 CEST schrieb Michael Walle: > > > These devices are more like an AT25 compatible EEPROM instead of > > > flashes. Like an EEPROM the user doesn't need to explicitly erase the > > > memory, nor are there sectors or pages. Thus, instead of the SPI-NOR > > > (flash) driver, one should instead use the at25 EEPROM driver. > > >=20 > > > Signed-off-by: Michael Walle > > > Cc: Uwe Kleine-K=F6nig > > > Cc: Thorsten Scherer > > > Cc: Marek Vasut > > > Cc: Imre Kaloz > > > Cc: Andrew Lunn > > > Cc: Flavio Suligoi > > > --- > > > The referenced binding only supports the true AT25 compatible EEPROMs > > > where you have to specify additional properties like size and page si= ze > > > or cypress FRAM devices where all the properties are discovered by the > > > driver. I don't have the actual hardware, therefore I can't work on a > > > proper driver and binding. But I really want to deprecate the use of > > > these EEPROM like devices in SPI-NOR. So as a first step, mark the > > > devices in the DT bindings as deprecated. > > >=20 > > > There are three in-tree users of this. I hope I've CCed all the relev= ant > > > people. With the switch to the at25 driver also comes a user-space > > > facing change: there is no more MTD device. Instead there is an "eepr= om" > > > file in /sys now, just like for every other EEPROM. > > >=20 > > > Marek already expressed, that the sps1 dts can likely be removed > > > altogether. I'd like to hear from the other board DTS maintainers if > > > they seem some problems moving to the EEPROM interface - or maybe that > > > device isn't used at all anyway. So in the end, we can hopefully move > > > all the users over to the at25 driver. > > > > So instead of spi-nor you want to use at25 for this MRAM devices? >=20 > Yes. >=20 > > AFAICS at25 is a spi only driver, but spi-nor is a spi-mem driver. So I= am > > wondering if at25 driver is capable of using QSPI hosts. >=20 > spi-mem support could be added to the at25 driver. But probably > mainly because there are SPI controllers out there which only have > an interface to attach memory (like the FlexSPI from NXP). Yes, FlexSPI is my current area of interest. > > Everspin EMxxLXB devices are capable of running in xSPI modes. > > Regarding QSPI (DSPI/OSPI as well) I assumed spi-nor is a given, but ma= ybe > > I am completely wrong here. Maybe someone could clarify this. >=20 > These newer devices should also support the erase command, right? So > they can be a "real" flash. If they support SFDP, the would even be > supported out of the box. The mentioned everspin devices are much > older and behaves more like an EEPROM instead of a flash. I see this is about older devices, I got misled by the subject. The new devices EMxxLX devices do not support SFDP. There are erase command= s, but unless you want to set sectors/whole chip to a defined state, this seems unneeded, so SPI_NOR_NO_ERASE would be sensible. I'm wondering if the comment in [1] is still applicable unconditionally, as there still is a use-case for spi-nor on flexspi. Best regards, Alexander [1] https://lore.kernel.org/linux-kernel/D0C9NCOMI27O.2VW2U3FNFTSPK@kernel.= org/ =2D-=20 TQ-Systems GmbH | M=FChlstra=DFe 2, Gut Delling | 82229 Seefeld, Germany Amtsgericht M=FCnchen, HRB 105018 Gesch=E4ftsf=FChrer: Detlef Schneider, R=FCdiger Stahl, Stefan Schneider http://www.tq-group.com/