From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 499793D7D98; Thu, 4 Jun 2026 08:36:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780562216; cv=none; b=ZiUOMUbbfk9aRhb474uWBm7OPOT0DeZAHl+jgFmonlETeTSnatn8VVG9bYIJSoi/q+U1ARicpabb/ZqnP2vVTuzVb2p40SKodzlPhqZk4rDoWNcO2G3OtE1mIqBN1Qkdkpm73+62W/R5vpcd9NGiLXaXEd19tMUyf86HZbWEydk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780562216; c=relaxed/simple; bh=+KBwoOcDHJ/gKB5QNN8WBfHE175dP+I++e/xL05rNAk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OY9//KnAQYiZP1URgvyJGsGgJ9cx+Cgcc2HQkRy1b2b29bD5zPAcH11/BYsfpfs/QVN0fjEqtPncVQaAk+u7ybGuL9FMsWl/xeUVDvvfaFxef3OAyJTPmFDuhuWyjpYvh9s58JmJYQL1xSm/pkokJ+di8Z2mkPXFH8Kb4tnuMOM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JFP86ilL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JFP86ilL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF7AB1F00893; Thu, 4 Jun 2026 08:36:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780562215; bh=+KBwoOcDHJ/gKB5QNN8WBfHE175dP+I++e/xL05rNAk=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=JFP86ilLCCHzhJlqAKq/rUnRl1SFMEP5JZc+9kfbd0g5Yyrj19XwaIgaXEo4lNSon KEC0GHXJ66zJqXcab7/+19KIRifpwdxz/H/PLecO5y8ITPQBOJNf9F0lpc/TJ0xBrE 2cQ9czqdmbN22/cC0Gtgt4ESBNsKcwak6Bp+huArDvhLcA76DrGPY82vjZy6ppj0qk MsKrXRNoMt7NYYudcD+4oV7ZtgZJF6JhPcUXduUHfIY6YtyDkIrp/Ezwgl86Uh0cgo R8ok/WBhqGzgaN6TcCvGv1Q+gc3IcyZCxPTmM5EUGKi8133ww+tf0JOvR3J39CUzY6 5ylbvc9KAvvYw== Date: Thu, 4 Jun 2026 09:36:49 +0100 From: Conor Dooley To: Miquel Raynal Cc: Santhosh Kumar K , broonie@kernel.org, robh@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 01/13] spi: dt-bindings: allow spi-max-frequency to specify a frequency pair Message-ID: <20260604-shrunk-acclaim-25368d7ad63e@spud> References: <20260527175527.2247679-2-s-k6@ti.com> <20260528-clergyman-kindling-20971775ba78@spud> <87cxy92llq.fsf@bootlin.com> <20260602-aptly-bunkbed-1bd3a8d63d54@spud> <875x3zzkji.fsf@bootlin.com> <20260603-neatly-twine-e89b923f5cb6@spud> <87o6hry4d4.fsf@bootlin.com> <20260603-balance-encounter-94f69e1577f3@spud> <87ik7yydyv.fsf@bootlin.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="I/LOsxQxq90rgY8F" Content-Disposition: inline In-Reply-To: <87ik7yydyv.fsf@bootlin.com> --I/LOsxQxq90rgY8F Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 04, 2026 at 09:14:16AM +0200, Miquel Raynal wrote: > Hi Conor, >=20 > >> >> > Right, and this I guess is what scuppers letting the controller d= river > >> >> > sort the configuration out itself and leaving the property as-is. > >> >> > It could be that the speed in spi-max-frequency is lower than the= "base > >> >> > speed" of the controller but because of board routing or device > >> >> > capability that the tuned mode is still required, right? > >> >>=20 > >> >> I do not actually expect any tuned mode/frequency to be mandatory. > >> > > >> > I think you misunderstood my use of "required", I meant that the new > >> > property/information was needed in the scenario I described, not tha= t it > >> > should be a required property in a binding. > >>=20 > >> Yes I misunderstood the term indeed. However I still fail to catch what > >> you meant here, I'm sorry. Would you mind rephrasing? > > > > I was talking about a scenario where you want to use the tuned mode to > > achieve the maximum rate because of the device and/or board configurati= on, > > but the rate is below the point where the controller would need tuning. > > Say the controller needs tuning above 8 Hz but the conditions require > > tuning to achieve more than 5 Hz. In this example, if the device can do > > 6 Hz, spi-max-frequency (in the current form) would be set to 6 Hz, and > > the controller would not enable the tuned mode, leading to problems > > because the inflection point determined from the controller compatible > > of 8 Hz would not have been reached. >=20 > I don't think this is a real situation. If the "conditions", as you say > (ie. PCB routing, mostly) require tuning above 5, then spi-max-frequency > should be 5. Then tuning mode would never be used. Remember, this is a theoretical world where spi-max-frequency would contain the tuned frequency and the controller was using compatible-specific speed thresholds to determine if tuning was required. > It is the frequency that is reachable without any > tuning. Tuning is just a plus. If tuning fails, we fallback to the > regular "base" speed, which just works. >=20 > Thanks, > Miqu=E8l --I/LOsxQxq90rgY8F Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCaiE5IQAKCRB4tDGHoIJi 0vh1AP4hwOVyHbur7c1ahOyaxI1idZEZt+yStGb1CnSi+78HSAEA5OgLzntrwzuS 46xL3MdoZvkkFkrRs+kEEXgrTZygVQU= =RuuS -----END PGP SIGNATURE----- --I/LOsxQxq90rgY8F--