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bh=BsbNWYH2izjNOlDmI6SDg0Mqw8LEsK+UeDW79yunUl8=; b=2mSyo6ob2XjgIYSC6YCVIviauScosz4++r4o2nlrcqQmCtc37rKKI/nelCWMCXnv7L5gwv kzg9BeDuf4FNeNKQPGgcMjGdrcz+6XdgWB+ALzXsfqlvu47abJSsUOA/BQ23IxpHUK4skv wDlqudx4SA6+bPFD02rtBT3LxbHaT86ovWvv5Ne8w48KiA6sa2bHAcCrAmUtAj4DsOMCBg SV0D9313Gthd0PjoA5TbUVXlLNvtxaQO4LszmbeY4APM6KvwVcRj4kreiL/Vgp+Fn4IwQ5 jhfX1+NJ06sOhFQ67Mx/we1is+1MPU6dM2U76t7+lxy2kHxLS3uK3vOKOP5JAQ== From: Miquel Raynal To: Rob Herring Cc: Santhosh Kumar K , broonie@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, richard@nod.at, vigneshr@ti.com, pratyush@kernel.org, mwalle@kernel.org, takahiro.kuwano@infineon.com, linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, praneeth@ti.com, u-kumar1@ti.com, a-dutta@ti.com Subject: Re: [PATCH v3 02/13] spi: dt-bindings: cdns,qspi-nor: add PHY tuning pattern partition property In-Reply-To: <20260602164945.GA475455-robh@kernel.org> (Rob Herring's message of "Tue, 2 Jun 2026 11:49:45 -0500") References: <20260527175527.2247679-1-s-k6@ti.com> <20260527175527.2247679-3-s-k6@ti.com> <20260602164945.GA475455-robh@kernel.org> User-Agent: mu4e 1.12.7; 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arc=none smtp.client-ip=185.246.85.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="2mSyo6ob" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id D62944E40115; Wed, 3 Jun 2026 16:01:13 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id A1B675FA0A; Wed, 3 Jun 2026 16:01:13 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 5AF7410888CCD; Wed, 3 Jun 2026 18:01:08 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1780502472; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=BsbNWYH2izjNOlDmI6SDg0Mqw8LEsK+UeDW79yunUl8=; b=2mSyo6ob2XjgIYSC6YCVIviauScosz4++r4o2nlrcqQmCtc37rKKI/nelCWMCXnv7L5gwv kzg9BeDuf4FNeNKQPGgcMjGdrcz+6XdgWB+ALzXsfqlvu47abJSsUOA/BQ23IxpHUK4skv wDlqudx4SA6+bPFD02rtBT3LxbHaT86ovWvv5Ne8w48KiA6sa2bHAcCrAmUtAj4DsOMCBg SV0D9313Gthd0PjoA5TbUVXlLNvtxaQO4LszmbeY4APM6KvwVcRj4kreiL/Vgp+Fn4IwQ5 jhfX1+NJ06sOhFQ67Mx/we1is+1MPU6dM2U76t7+lxy2kHxLS3uK3vOKOP5JAQ== From: Miquel Raynal To: Rob Herring Cc: Santhosh Kumar K , broonie@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, richard@nod.at, vigneshr@ti.com, pratyush@kernel.org, mwalle@kernel.org, takahiro.kuwano@infineon.com, linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, praneeth@ti.com, u-kumar1@ti.com, a-dutta@ti.com Subject: Re: [PATCH v3 02/13] spi: dt-bindings: cdns,qspi-nor: add PHY tuning pattern partition property In-Reply-To: <20260602164945.GA475455-robh@kernel.org> (Rob Herring's message of "Tue, 2 Jun 2026 11:49:45 -0500") References: <20260527175527.2247679-1-s-k6@ti.com> <20260527175527.2247679-3-s-k6@ti.com> <20260602164945.GA475455-robh@kernel.org> User-Agent: mu4e 1.12.7; emacs 30.2 Date: Wed, 03 Jun 2026 18:01:07 +0200 Message-ID: <87zf1by5oc.fsf@bootlin.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Last-TLS-Session-Version: TLSv1.3 Hello, On 02/06/2026 at 11:49:45 -05, Rob Herring wrote: > On Wed, May 27, 2026 at 11:25:16PM +0530, Santhosh Kumar K wrote: >> PHY tuning requires a known data pattern to be readable from flash. >> When no partition is explicitly identified, the controller must search >> all available partitions to locate the pattern by label, which adds >> overhead and relies on label naming conventions outside the >> controller's control. > > I agree 'label' is not the best choice. Software should not care what=20 > 'label' contains. It should really be 'compatible' instead. But compatible does not seem relevant in this case, right? We are just flagging the location of "some useful data for the controller". >> Add cdns,phy-pattern-partition, a phandle property that allows the DT >> author to directly reference the flash partition holding the PHY tuning >> pattern. The controller uses this partition during calibration, avoiding >> the partition search entirely. > > Do you have any data that this approach being "direct" is faster? In=20 > fact, it might be worse. Instead of searching just the limited number of= =20 > partition subnodes, you now search the entire tree for a matching=20 > phandle value. We do have phandle caching, so that might save you > here. True, but besides performance considerations, I personally do not find elegant using a partition name/label, but maybe that's just personal taste :-) Thanks, Miqu=C3=A8l