From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D85AC433DF for ; Tue, 30 Jun 2020 19:45:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC663206C0 for ; Tue, 30 Jun 2020 19:45:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728379AbgF3Tpc (ORCPT ); Tue, 30 Jun 2020 15:45:32 -0400 Received: from sauhun.de ([88.99.104.3]:55622 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726072AbgF3Tpc (ORCPT ); Tue, 30 Jun 2020 15:45:32 -0400 Received: from localhost (p54b336a9.dip0.t-ipconnect.de [84.179.54.169]) by pokefinder.org (Postfix) with ESMTPSA id C3ADA2C2066; Tue, 30 Jun 2020 21:45:29 +0200 (CEST) Date: Tue, 30 Jun 2020 21:45:28 +0200 From: Wolfram Sang To: Geert Uytterhoeven Cc: Ulrich Hecht , Linux-Renesas , Linux I2C Subject: Re: [PATCH v2] i2c: sh_mobile: implement atomic transfers Message-ID: <20200630194528.GB999@ninjato> References: <20200618150532.2923-1-uli+renesas@fpond.eu> <20200625070636.GB970@ninjato> <20200625151658.GB1041@ninjato> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="V0207lvV8h4k8FAm" Content-Disposition: inline In-Reply-To: <20200625151658.GB1041@ninjato> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org --V0207lvV8h4k8FAm Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 25, 2020 at 05:16:58PM +0200, Wolfram Sang wrote: > Hi Geert, >=20 > I spend some more thoughts on this. >=20 > > > > In general, pm_runtime_get_sync() is not safe to call from atomic > > > > context. > > > > For Renesas SoCs, I think both the power and clock domains are safe= , as > > > > the respective drivers don't sleep. The PM core might, though. > > > > > > Still, that sounds to me like we should protect these calls as in V1? >=20 > I still think we should guard these calls just because it is not safe to > call them from atomic contexts. >=20 > > And talk to the i2c controller while it is disabled? >=20 > Is there maybe some "always-on" property which we could add to the > respective IIC clock? Ping to this question... >=20 > > That does seem to work on R-Car Gen2 (similar to SMP bringup accessing > > registers of a disabled WDT?), though. >=20 > Yes. Uli's patch will not cause a regression because we are already > calling i2c_transfer very late. And we do call the runtime_pm functions > currently. So, it will improve the situation there. >=20 > > Needs testing on R-Mobile A1.... >=20 > That's armadillo, right? I don't have that, sadly. >=20 > Thanks, >=20 > Wolfram >=20 --V0207lvV8h4k8FAm Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAl77llgACgkQFA3kzBSg KbaxzBAArrt8SbV9ATqgzXjOKZNWpNTsHMNQdXQtE2Wu88NcDZUsb4oUMpTCWcam 7ObyR30xttvvFwVOJtHsNs45qN0qpVjXleP2P3jLZDwjXx283w3dvYeBLRJCMg0B YkaUu4Om0RZsnmmlhlqhd4iBQtVW8ZYqH6kIJbne0XW+g2i2lzbB8ozFkyV8GoDi dRDSVJr7S/mI98Kiu1ST6WyRfkyBcpSlO5dTmCA53nZ8xSDWdrvddCipvVzEbcsW YWbGxI3Xeg07AkWOETkhCKbliTeEotn2fNtehiWfwguID9xg7BtJq8OE2GAW9f2U r/hPGMS8AYsK8IxO/pM5UMGF7s17ie/QRftaasB5SI9mPB11+FvHW2mnPHpuOjvA vbZQzwsuEB0OcvmAwFEwZy+AbcPhPRVUgJfKuxZaRR+R+n/i4uDVY43FkGKQhpsr NfcZlGv54NrFdalldFTnb9PgANP/gAdWBVwVhhuelqyKi1YkQrq0Rv/M8oZJUTYI mBd1YNH7cNGjrVvnUKJzIEgiAsjFSoWVg5e4zvFbJ02wWqC7uwZDxPfUAMXaDSpT ApohbDFMnDK8b8nj1ZIpxxThs3B2u9FgRJnbyblJsMfYm0COW2/v4nN1rSE2SXhD merrSRqnq0umA+RBpaDaLBdSQSZSJDyjS3+YdjiUQp792/D1iyQ= =BmBg -----END PGP SIGNATURE----- --V0207lvV8h4k8FAm--