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 B602237701C; Mon, 22 Jun 2026 12:14:43 +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=1782130484; cv=none; b=ELB6Z+KFUmDmFCEfACV2dcZaJhrleL79KYL9D/TiTevdjDhaewTmHGBvGkWaZOCwkHiuBWyeTBUXRRGUedBuPCLhhLKAA+oLjCsOtA28TO227n0QdWTGVAf6IeFAoGDpaqkVbtRliC8qZioXr6sqTgA4VX8yGv4miYxfZokmR9Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782130484; c=relaxed/simple; bh=TMGyjSuWg9NEotd+ahz9PPBUPALrJMSkHgos5n7VfdE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nyve+Otpcd+tKoZ9gQYrvXqYM5E3zBwtY/T/vtEBtAEkro9j70jFUbK7SuL28EyXkOecsJxi19RiGVR564yUrKkyilw9XJbYoISb77aYtObBGQ3OAntI5hD+5EMJ2KqmnGEQ9DiCJsqAkn8oVsfdxFZhqnWhkjN/hf7eaSbfkXY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Nf6bH7JR; 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="Nf6bH7JR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 959421F000E9; Mon, 22 Jun 2026 12:14:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782130483; bh=PLzfOePcr71pjgrrJIYMsZNq9tAcTr1Q5rZ9mAkZxo0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Nf6bH7JRmYestHJ6L5m7duxYhRmWPOlDCJkaF+6uIb07B0HpySfeSvBy9Vsld9KsR 6QkZZOcWVxOWY2mdnucSs02EufXWFmvs+R/kSoI+pFSJ2u24c2y0y5LEeIoTq7ns5a ud9n2/EKWbmnlpx4pHEZZpHpPJJW5f/hJc8hicy1Q2oB7UXM0QnbOzdUjktW+0MveK 6Ncj7Te+k7gzeaCGFHP9dSmTw2PywEq6AfFvPS5x055SfzV8hegsFUBBbjQn0ZC9ty w+6Mr0WFWuQC6A/HaVPIP0QhP+Jf+swK+1BEmiIH2BUcXWKVfg3/Z+zTs0a7Od1qd+ 8WIqU4JGCb3cA== Date: Mon, 22 Jun 2026 13:14:37 +0100 From: Conor Dooley To: Janani Sunil Cc: Nuno =?iso-8859-1?Q?S=E1?= , Jonathan Cameron , Rodrigo Alencar <455.rodrigo.alencar@gmail.com>, Janani Sunil , Lars-Peter Clausen , Michael Hennerich , David Lechner , Nuno =?iso-8859-1?Q?S=E1?= , Andy Shevchenko , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Philipp Zabel , Jonathan Corbet , Shuah Khan , linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Mark Brown Subject: Re: [PATCH v3 1/2] dt-bindings: iio: dac: Add AD5529R Message-ID: <20260622-overbid-yonder-3fdfee9eda7a@spud> References: <20260619-bunch-diocese-dd7805cc17ff@spud> <20260619-concierge-doozy-9c161533c369@spud> <20260621153330.79b6600c@jic23-huawei> <20260621-nutmeg-coauthor-715189372230@spud> <20260622102722.5900592f@jic23-huawei> Precedence: bulk X-Mailing-List: linux-iio@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="8y2QeyvUNb6GDuqi" Content-Disposition: inline In-Reply-To: --8y2QeyvUNb6GDuqi Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jun 22, 2026 at 01:54:25PM +0200, Janani Sunil wrote: > > > > > Why do you think the microchip devices won't work? Does the spi c= ore > > > > > reject multiple devices with the same chip select being registere= d or > > > > > something like that? > > > > Not sure how things work atm. But I'm fairly sure it used to be like > > > > that. SPI would reject devices on the same controller and CS. Now t= hat > > > > we support more than one CS per controller, not sure how things wor= k. > > > We always supported more than one per CS per controller. I guess you = mean > > > per device. > > Obviously :) > > > > Janani, maybe you can give it a try? > > > I think we'd need to get it to work with shared gpio proxy which maybe > > > will just get set up under the hood. This used to be opt in, but see= ms > > > that changed fairly recently so maybe some of us are working with out > > > of date knowledge! I haven't played with it yet, so might not be > > > that simple. > > >=20 > > What I meant for Janani was basically testing two devices on the same CS > > as in my pseudo DT. For the GPIO, you mean having a way to select > > between devices on the same CS? > >=20 > > For these devices the pin id numbers get's setted up as part of the spi= message > > so my assumption is that all of them will receive the message but only = one acks it. > >=20 > > - Nuno S=E1 >=20 > Hi Everyone, >=20 > I tested the case where there are two devices on the same CS. The SPI cor= e does reject it at spi_dev_check_cs(): > https://github.com/torvalds/linux/blob/master/drivers/spi/spi.c#L631 Can you try again, but delete that check and allow the code to continue? Worth knowing if the problem is policy (which makes sense for 99.99% of devices that cannot share a chip select) or actually not supported by the spi core code. --8y2QeyvUNb6GDuqi Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCajknLQAKCRB4tDGHoIJi 0vvHAQCAmeichsIP4bHRKwfnmk99xZ27BMSq9pUtwpPzW/19QAD7Bf5jclNg0xtX usoMbgm6dKZ+hjsZOwVQ/1WyKLl2egI= =MAat -----END PGP SIGNATURE----- --8y2QeyvUNb6GDuqi--