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 D9BF839A7F4; Fri, 5 Jun 2026 15:21:05 +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=1780672866; cv=none; b=Vr1VNCvjUJgXMsoxRpqoEJ/amlWaFcF5FHev++98Muf0xl9JuYp5ObvO7FRI2YTytVqDXL01qwq9e6VaiaKHaAEftJ8hykSuFA80zFN5W9NFY70BygLeMACe9gQW3AewYxCi/JrtkFRj8+MnIik4WKE9e/7CdfJB3voJ7IxoAgk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780672866; c=relaxed/simple; bh=vw91GZNtqBFohd/dG1WeoM+tMXZptKE7kVHQJDsCpOs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XnQ8OXrh3rNeaTehFpdKdkhSJbNWu1op9GYTjwjwB/XyMc+XTISYP1OIoUEgeqUgJnk9xQ7PULoXKVN08fENaABeJH2Gq4LxQRm/zkj2XFaLcQHD0svOmxOxMQIDim16aHzpbuKXoQk5FOYTkaYRHfHmXki8wsjcvq8JfMQGBwI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QrD1vjtK; 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="QrD1vjtK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A43C1F00893; Fri, 5 Jun 2026 15:21:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780672865; bh=vw91GZNtqBFohd/dG1WeoM+tMXZptKE7kVHQJDsCpOs=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=QrD1vjtK+SkysmU4faIqnr8ZN6m9IEZx4MtrX9q2kfLLNKJzB3Dy3rRqj6etwUTX3 H5+h1QlUbbXgkXEdyMhmOsLNj+Zo+RKomonT2jiUT9Xxj4q43D2Mhn+qrKnzubTxw+ eIiQ/F4T1QScIFYEYDxbn8PZ9vGvGVJi1M6t/TKjqfVOW9FH2WWqO/Zt/DqdoDco9r 1OhvnXMmT0/QSlObCncM+8K0HqAG62kbceKT4okzLYR7ZjPZHtcz4xmfzZgV6fCNW5 HaFVmQEK66fCAmwFHeVMeu1bZy6Zb8O4g0ty7qsZw2xsRZIwbU7SAhMNt7LDogjxFR zgnuXdGDgRS6g== Date: Fri, 5 Jun 2026 16:20:59 +0100 From: Conor Dooley To: Miquel Raynal Cc: Conor Dooley , 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: <20260605-cane-duct-a5c740fae417@spud> References: <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> <20260604-shrunk-acclaim-25368d7ad63e@spud> <87a4t9wl7r.fsf@bootlin.com> <20260605-regulate-crawling-253c6d6bd971@wendy> <87tsrh4fe2.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="n7CCSV6H7UyMc2Oa" Content-Disposition: inline In-Reply-To: <87tsrh4fe2.fsf@bootlin.com> --n7CCSV6H7UyMc2Oa Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jun 05, 2026 at 09:26:13AM +0200, Miquel Raynal wrote: > On 05/06/2026 at 08:17:18 +01, Conor Dooley = wrote: >=20 > > On Fri, Jun 05, 2026 at 08:32:56AM +0200, Miquel Raynal wrote: > >> On 04/06/2026 at 09:36:49 +01, Conor Dooley wrote: > >>=20 > >> > 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 contro= ller driver > >> >> >> >> > sort the configuration out itself and leaving the property = as-is. > >> >> >> >> > It could be that the speed in spi-max-frequency is lower th= an the "base > >> >> >> >> > speed" of the controller but because of board routing or de= vice > >> >> >> >> > capability that the tuned mode is still required, right? > >> >> >> >>=20 > >> >> >> >> I do not actually expect any tuned mode/frequency to be manda= tory. > >> >> >> > > >> >> >> > I think you misunderstood my use of "required", I meant that t= he new > >> >> >> > property/information was needed in the scenario I described, n= ot that it > >> >> >> > should be a required property in a binding. > >> >> >>=20 > >> >> >> Yes I misunderstood the term indeed. However I still fail to cat= ch what > >> >> >> you meant here, I'm sorry. Would you mind rephrasing? > >> >> > > >> >> > I was talking about a scenario where you want to use the tuned mo= de to > >> >> > achieve the maximum rate because of the device and/or board confi= guration, > >> >> > but the rate is below the point where the controller would need t= uning. > >> >> > Say the controller needs tuning above 8 Hz but the conditions req= uire > >> >> > 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 H= z, and > >> >> > the controller would not enable the tuned mode, leading to proble= ms > >> >> > because the inflection point determined from the controller compa= tible > >> >> > 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-freq= uency > >> >> should be 5. > >> > > >> > Then tuning mode would never be used. > >>=20 > >> Well, this is exactly what we propose in this series, a way to indicate > >> two maximum frequencies, one that just works (like before) and a higher > >> frequency that is only reachable after an extra tuning procedure. > >>=20 > >> > 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 determi= ne > >> > if tuning was required. > >>=20 > >> That is not what we are proposing. I don't think indicating the "after > >> tuning" frequency in a property that has long been used for an always > >> reachable frequency is wise. Hence either the use of an array (the > >> second entry could contain a higher frequency) or a secondary > >> spi-max-frequency-whatever property. > > > > I am/was trying to come up with a scenario that would justify the patch > > man, stop trying to interpret it as what I want done. >=20 > Ah :-) Sorry the intention was unclear to me. So what is your preferred > take in the end? I think the generic dedicated property makes the most sense to me. --n7CCSV6H7UyMc2Oa Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCaiLpWAAKCRB4tDGHoIJi 0if4AP9/WM+AK0u5JheOzThGNxZOzx0f/LbnrVw+eUcxqqq1zAEAhHeg2ZUM0hWt Wobi1Twk/64oObefh9HxMBtDl6GhxwY= =/wCv -----END PGP SIGNATURE----- --n7CCSV6H7UyMc2Oa--