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=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 E0C93C4363A for ; Thu, 29 Oct 2020 18:00:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E07B20796 for ; Thu, 29 Oct 2020 18:00:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603994408; bh=AZhOU2W6PRWrW++sUwojyV8r0hQKprOKEkuphmHahJo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=0TOjQnI5YAMPyYFBmXpklpd1QxIL/DuFWCnuLtoazUgJUaVCKk1Qrnx8eFIWUnQ1D 3OORMaVOfbLo57WNzqzJVP9EIc4F9n6utNYDVlDoYDw4AN1UCXMhai6LMp+3vDktYZ Ukt01sK25iGear/ZdvL7GJOrW/NvpcNnVIgzD+Cg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725775AbgJ2SAG (ORCPT ); Thu, 29 Oct 2020 14:00:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:53434 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725613AbgJ2R7v (ORCPT ); Thu, 29 Oct 2020 13:59:51 -0400 Received: from localhost (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 85B6F20790; Thu, 29 Oct 2020 17:59:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603994390; bh=AZhOU2W6PRWrW++sUwojyV8r0hQKprOKEkuphmHahJo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pIEzdSBlrcWxEoEuNilbOwp5u8kO4Q26+P+M2ItJj0B4B0jOS8vPB+rK7f2uCMBqP E3CxhD3RUIbUpQkg5ZEUJwilewx80cqkLghXR+y/A1dSSuVeWgjXf2lgGqjSyDk52y C9cxJ8EjkUqHMLg6YkSrTj7sn2nNt4mOikajvZsA= Date: Thu, 29 Oct 2020 17:59:43 +0000 From: Mark Brown To: Ezequiel Garcia Cc: Robin Murphy , Adrian Ratiu , Philipp Zabel , Fruehberger Peter , Mauro Carvalho Chehab , linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, kuhanh.murugasen.krishnan@intel.com, Daniel Vetter , kernel@collabora.com, linux-media@vger.kernel.org Subject: Re: [PATCH 00/18] Add Hantro regmap and VC8000 h264 decode support Message-ID: <20201029175943.GE5042@sirena.org.uk> References: <20201012205957.889185-1-adrian.ratiu@collabora.com> <0dd9fb9d-3f33-b9b0-a7a8-6d3111e92d64@arm.com> <5a653c86f887bf8f3d34c4d620471300b612a4d8.camel@collabora.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Rgf3q3z9SdmXC6oT" Content-Disposition: inline In-Reply-To: <5a653c86f887bf8f3d34c4d620471300b612a4d8.camel@collabora.com> X-Cookie: Monotheism is a gift from the gods. User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Rgf3q3z9SdmXC6oT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 29, 2020 at 01:27:08PM -0300, Ezequiel Garcia wrote: > On Thu, 2020-10-29 at 14:15 +0000, Robin Murphy wrote: > > Or maybe the regmap API itself deserves extending with a "deferred"=20 > > operating mode where updates to the cached state can be separated from= =20 > > committing that state to the underlying hardware. > > ...which, after a brief code search out of curiosity, apparently alread= y=20 > > exists in the form of regcache_cache_only()/regcache_sync(), so there's= =20 > > probably no need to reinvent it :) > To be fair, and despite it could seem an anti-pattern, this particular > wheel is so tiny and trivial, that I'm starting to seriously consider > reinventing it. > I've been thinking long about this but just can't seem to see exactly > what benefit we're getting from using MMIO regmaps here, > as opposed to just a simple macro with an index, a mask, and an offset. As a rule of thumb if you're not using a cache or fitting into some other higher level framework stuff that uses regmap then I wouldn't bother for MMIO devices. --Rgf3q3z9SdmXC6oT Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl+bAw4ACgkQJNaLcl1U h9BrSAf/dmEzyzrzFZNPwE6FzIAV8o45wj261p4lQVkPR6Vl5CvsVKpC+h8d9ArY t3plejxUu4tD6bQxgr4Z8hH21CstLRRfTBvMxw3B30qRx+WjCcoUp3ITBvQ4un9G wUQsSkBqR9sbYFROEenraceUC4digdUJ4zUF+UKtmLcOH/qmrio1PSBsJyOugFRd KHp5PxSUG18I93T1S/MLSuxpi11ZTvgXp3g41eDRia+joSz7OAHbTkeMsn8vkLYy rMJpJDOC/UN+lOMqM7XLaD6nuY3jVDVoJqRPFDHOij/tPaDOmScjK4RRvWQwyNR3 OV4/0EqCGUf6z5RAwF6t6yedKSYzSQ== =uxou -----END PGP SIGNATURE----- --Rgf3q3z9SdmXC6oT--