From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zeus03.de (zeus03.de [194.117.254.33]) (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 56431402426 for ; Mon, 11 May 2026 15:39:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.117.254.33 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513958; cv=none; b=Ae8LLoCRcTRXHbfuz3mWdep5UCa3+NyEwnac2uOdybuPDw9yGW3VhhU7e0APBBvamX48IKz15qfpiHcbd6cLumYPWYGzFgSEkkvaHZJNtLyckSa8+24xtUALlRBzrDGN+yX6MCy44bMSRzACT9TqX45/VElQiFdeuKUQpU73UG4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513958; c=relaxed/simple; bh=MSAKLrOMeVtUXrdQMu5EnltEbk6TAoSyUpejlgS/hmk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tNW3GxMNvVXqjgYALzalc1IM+raOw6bNcYhwytRf8K7Fkh4/kwsfdTww7ERsc7ZxIDJgQUmt/Pgfh1BunCHV9RDoL44NWQsRjsgUUe/4OHMEqLv4rD4Ie2WrFpLGsEa3rldlA0LmNyxK/ZKFF7XSKECK2cDlaExxF0fKMAe+7pM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com; spf=pass smtp.mailfrom=sang-engineering.com; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b=VRldLf8a; arc=none smtp.client-ip=194.117.254.33 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b="VRldLf8a" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= sang-engineering.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to; s=k1; bh=MSAK LrOMeVtUXrdQMu5EnltEbk6TAoSyUpejlgS/hmk=; b=VRldLf8aewNL2O/C2JAu VCMKEKYZX9+cevIflsskCzZ/ZvLOXSX49I5bwfoT4y6V2ajHr75N+hKpBGlCqtw0 T73RpLBLnm5nKaLkRu4prBlQmJ7ffPPWf95b0RjSEk4BuwtygoVJKDe/Ct4hMgbz sECm20HpNbc9gmypEs5tCDdJqN0aJapNnDHwZ5RpcU4+JbG02UzAX0/c1Gw8OApF kLYnU+eWd1tredl6A4tyxaWdzt/emjd+CT/kqaXdoPBsQtCLlpINEKnlveYTKAyT Q9reGHdO4DGsJYYYt2F7GQhv4UGJOlEMijRI4PtWOrRMITY51b4USh/1DmKZTSFt 1w== Received: (qmail 2642381 invoked from network); 11 May 2026 17:39:09 +0200 Received: by mail.zeus03.de with UTF8SMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 11 May 2026 17:39:09 +0200 X-UD-Smtp-Session: l3s3148p1@LiEzjIxR0pYujnue Date: Mon, 11 May 2026 17:39:08 +0200 From: Wolfram Sang To: Bartosz Golaszewski Cc: markus.stockhausen@gmx.de, andi.shyti@kernel.org, linux-i2c@vger.kernel.org Subject: Re: AW: [PATCH 1/2] dt-bindings: i2c: Add i2c-shared-gpio Message-ID: References: <20260507181711.2696783-1-markus.stockhausen@gmx.de> <20260507181711.2696783-2-markus.stockhausen@gmx.de> <20260508131830.GA1135235-robh@kernel.org> <007a01dcdef9$05ba7140$112f53c0$@gmx.de> <00ef01dcdff4$42318c70$c694a550$@gmx.de> Precedence: bulk X-Mailing-List: linux-i2c@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="Z9YnADdDyeospyf9" Content-Disposition: inline In-Reply-To: --Z9YnADdDyeospyf9 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > >> @Bart: is it possible to share a GPIO so that multiple i2c-gpio > >> instances can use the same GPIO as SCL? Use case is explained in the > >> cover letter[2]. > > >=20 > The way it works is with a kind of a voting system. As long as there's at > least one user that votes for the GPIO to be "high", it stays high. Is th= is > behavior fine for the recovery use-case? Ouch, I guess this will not work then. SCL is high in its idle state. So, all busses except the active one will request high :( I guess Markus would need some kind of locking for the shared SCL-GPIO anyhow. Like bus Y has to wait until bus X has finished SCL toggling for its transfer. That's how I understand it. --Z9YnADdDyeospyf9 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAmoB+BgACgkQFA3kzBSg KbYKdg/9GifAR9WaIkCVQud7aSXG8sX0UYrqWNi4X3BYDQVXAor01W3TxRcPOvn1 iIu30ifdrZZV5hpqTr2aAcxNbNaiULxrRgTetsksdh7r47gABuR8bBPQuz5fTDis aGyTOrgvpclvBzzdTCrVn+HuxTeBGSzI1yGePliyc2y4xj2c9t6kwVAeggs39pY4 5nWZO1/P1Ya36rv5en2QhEIEDqlZ2Crau+CgV3L6tqsw7Y6C30blsiZkglebyt4d L48dS/xjOdxu7JQtH0U9M726V69z2qi8SZjGhL0IC/ZtBNxlOopCR/rqGUuymtPw QuB0vn7rspwz8qeOieMd4QZy1PWA29V6X3uJeaCBRUbLa+Ncb7mF+0rGIn4qeOAd tS2gp5evHGd5KFkGvUjyvKn8IbACIx/fkAp9hmU1/mpVGUEiWZn+3nKcwfcDY1GX cgeqGuyisDWIET/Ayer0eNpgW0X/AI4qQBMu0YYElSdSukMAC45/Ko0v3gxqaHNL brm+b1f5T2QgkFQMYMlwLia05t1rig2fuDXrKKBEGkPQ/6f3MAVfIZne8MSSLgbL +sEpPQa17xjsXi+dyn2puwl1JjU7QuqH9QsT57defv3te3iZ2qIMbdJ+sRr/19TW friMYB84FrMHlQkKZ1fKZpPMydNN972lKP/gM+uDSP6bF3Jt3Uw= =dRWa -----END PGP SIGNATURE----- --Z9YnADdDyeospyf9--