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 632E03FDC04 for ; Tue, 26 May 2026 16:56:01 +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=1779814566; cv=none; b=Sn6RnGjwGo+2Jmk/LOHKInHUxSYaCEv6GAVvuNomDVkZ0EOBH3pmI1EcaukKAblauVuT5XSnlk4SNUYEZZ2xx1B9SQuCr7gffUkxuxaB4B7nnIuQbe30rnxkvRCri+3/RAjsvck6C3rvfZP+WehO1LAbrzqJTjo8ZsuQc2JckWU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779814566; c=relaxed/simple; bh=jcvxe0BxKUGlhCARFFb0VfNaSr35iqpLwDgjTvYbWbo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=czyXdsZXh7Hx32pqVCUlimskAyYjkHVZcZbpDuovnWy32eqN00pUaGJ98/fs/E05l/UNHgR1nsz/4zLmooyAdyot6AtjpLieyNg4LJae8gg8oxEgBjAwO9MJLJBZLfuryIbSFmC/6/vdTkdw0rrblmRLsXVavITokglQGL5wcHo= 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=Dd0BeatO; 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="Dd0BeatO" 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=iD4T UgyB93O/7A4XIuVqz7PsEYOPEYYUIwqRRLojrlg=; b=Dd0BeatOVZAj3xpfzQAh KnUoPIDJ8NWUejDSq4Nysb4amCCYSdyoPCTpXEKCPiGOdrCc84QmxVJBOmZJ43ZR lO7C5tlONbLsWpwhJ4ZKJpxZ9/5/Tg4XWjHketwWiyh0/m7RJ+BFFOkuupfg1uzG HVehMQhjHUUGuEagJdN07lUgRoRC+TKOLKBBQk/MhOozvMuc2yLKWhH+M7Lruz6e p4x2V3lviNnFd8x63urTwsQTDeR+XxdjTIbuOL7+VCc/KpmkhSKPv+I1d02JSiZO DeH+nnmadj8CWbVCvRc/MebKAnFT7n7QPEFN2FgEqlSr0A9HBPl07EipOuysLabA Gw== Received: (qmail 346646 invoked from network); 26 May 2026 18:55:59 +0200 Received: by mail.zeus03.de with ESMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 26 May 2026 18:55:59 +0200 X-UD-Smtp-Session: l3s3148p1@6/WMXrtS6HWSAB7I Date: Tue, 26 May 2026 18:55:58 +0200 From: Wolfram Sang To: Claudiu Beznea Cc: geert+renesas@glider.be, linusw@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, magnus.damm@gmail.com, claudiu.beznea@tuxon.dev, linux-renesas-soc@vger.kernel.org, linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Claudiu Beznea Subject: Re: [PATCH 9/9] arm64: dts: renesas: rzg3s-smarc-som: Enable I3C Message-ID: References: <20260522102251.1723392-1-claudiu.beznea@kernel.org> <20260522102251.1723392-10-claudiu.beznea@kernel.org> Precedence: bulk X-Mailing-List: devicetree@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="qag9In8SilDNru8h" Content-Disposition: inline In-Reply-To: --qag9In8SilDNru8h Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Claudiu, > Could you please let me know what do you consider we should do here? Do y= ou > think we could drop these pin controller setting and do some particular I= 3C > controller settings instead? My original thought was: If it was a boolean state which is active when suspending and disabled when resuming, then we wouldn't need a customer specific binding for it and just do this in the suspend/resume functions of the pin-controller... =2E.. BUT ... reading more about this in the manual, just raises more questions for me. > The output is fixed at Hi-Z and no data is transmitted to the inside even= if > data is input from outside. =E2=80=9CStandby mode=E2=80=9D is available w= hen using I2C mode > only. (Not available when using I3C mode). >=20 > The current driver proposal don't take into account the IP mode when sett= ing > STBN though > pinctrl_pm_select_sleep_state()/pinctrl_pm_select_default_state() to keep > the code simpler, relying on the "Not available when using I3C mode" part= of > the note, and considering setting it when the IP is in I3C mode is harmle= ss. This is one question I also had: What does "not available" actually mean? Did you confirm with HW guys that it is really harmles? I also wonder about the intended use-case of this mode. "no data is transmitted to the inside even if data is input from outside" doesn't really sound like a mode intended when the whole SoC goes to sleep. Why or how would input be even transmitted to the inside if everything is in a deep-sleep state? I could also imagine that this mode is rather used to hide from the bus for a while for some corner-case reason. And finally: does this really save energy? Could you measure a benefit? Maybe there is nothing driven at all in the sleep state? Then, nothing is gained? Not clear from the datasheet. Because the datasheet is so sparse with information and because it doesn't say how STBN is intended to be used, I would argue we should skip it until we know what it is for and how it is used. If we know this somewhen, we can still add this in a second step. But for now, enabling I3C realiably is the first step, and for that we surley need the POC bit to select the voltage. This is easily understandable and straightforward to do. So, my suggestion is to pick this low-hanging fruit now and reach for the other one once we have more information about it. Happy hacking, Wolfram --qag9In8SilDNru8h Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAmoV0JoACgkQFA3kzBSg KbalBw/+PYGp79tAsAoZgns4CGQEnSzrX3Mo9NVfIuKw8bfup2uQw2LOUcD9IOpZ 8Sr5nCdCvV+Le1pXslt4wLq5Iry3b95kQZsvJh99o6rNXrYUjnidAXnWabM/uNyc weSvVlMCpxttD08lBFnlEuG1UktU1xs+hAFrphmYvuhw0slyWceBT3TFBbigBztU mpbPzppKp0p6UqarAYu/ZjhtxkjBV+p752dPmjLvhpluGxpvzcjiLE8BExqMtflf tniL3L6Oaszw2XwtbmK2+O4oYo1+gE9uFLLxY+84cQ64vffT5+I1Wztvw9OYXZMV NCstKOwK5o7G7ulIw8YgkGAi8g6IfVSt8Qu8xne8/1CArOGoZCMH5BWOCfn2niJK OdCWG36DAorKHhQ+o1Kw5wvcqb5oIl0+0LeFxt7aY0CB2WLCsWDSBjwSFN0jByvW FOHktnPDQQydIuzFckuV5Kfobe98weAI0kqHBYBNrsohUFNzZY882RZY11Gplp+Y o+J+Kc10BidYpqVZWSQGek+YiVxsrra2RZA6rohl+cS8KhJvVBvr+PAKMHhEdmF3 V/elSBH3RuV4wv2qMA+Bs4KiRlbUq0K54iDY+QH79/9TVwqtzoTKy6wj/oO/4Ogn vs6onVlVXI75DPdZH8BADVz+utkkzPXKF7kukcNs3c7F6/E6yyA= =C2e+ -----END PGP SIGNATURE----- --qag9In8SilDNru8h--