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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65D96C4332F for ; Tue, 8 Feb 2022 15:18:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351748AbiBHPSY (ORCPT ); Tue, 8 Feb 2022 10:18:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239424AbiBHPSX (ORCPT ); Tue, 8 Feb 2022 10:18:23 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA73BC061576; Tue, 8 Feb 2022 07:18:22 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5610761599; Tue, 8 Feb 2022 15:18:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 071E2C004E1; Tue, 8 Feb 2022 15:18:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644333501; bh=9zUs0iuzKwulU200Q6NMliFAJbLi0oQzH9htLDfo/j8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jec8CourqxGwtOULAuUJQ2M06wpyEydYcArcgJdKsAi2pDpknemzA3PLWTfMKSj7k UDzxVpfxINAj6NXq1W4KUyDdHKyM51z62OlSYsrEJOcVZbQybOEJNB6Y/FESnlSAdw s+kZ3C6+D9EpV9zfi/4v42c21hn321m0WQijY487BF3RlwwxK4RXsiIFqskCZKGg2X YZWojAT2oRg5AxPl4e2OOP/6DUinHkbXLQ7JADrUsYjDmOza9sAg5gbYVmYEefXPVj HhDLH0L2g/iD0eNGQf+ZyGAUmEYBS4BjNfqd7OdQKIK7dCh/DYx+/uRVmhDXdrYyYv JIrzOMR83Rk4w== Date: Tue, 8 Feb 2022 15:18:14 +0000 From: Mark Brown To: Javier Martinez Canillas Cc: Geert Uytterhoeven , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Linux Fbdev development list , Linux PWM List , David Airlie , Daniel Vetter , Linux Kernel Mailing List , DRI Development , Liam Girdwood , Rob Herring , Noralf =?iso-8859-1?Q?Tr=F8nnes?= , Thierry Reding , Maxime Ripard , Thomas Zimmermann , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Lee Jones , Andy Shevchenko , Sam Ravnborg Subject: Re: [PATCH v2 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays Message-ID: References: <20220204134347.1187749-1-javierm@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="6nCHMM5kfVPLymNn" Content-Disposition: inline In-Reply-To: X-Cookie: This is your fortune. Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --6nCHMM5kfVPLymNn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Feb 08, 2022 at 04:10:49PM +0100, Javier Martinez Canillas wrote: > On 2/8/22 15:19, Geert Uytterhoeven wrote: > > - "time ls" on the serial console (no files in the current directory, > > so nothing to print) increases from 0.86s to 1.92s, so the system is > > more loaded. As ssd1307fb relied on deferred I/O too, the slowdown > > might be (partly) due to redrawing of the visual artefacts > > mentioned above. > I was trying to first have the driver and then figure out how to optimize > it. For v3 I'm using regmap to access instead of the I2C layer directly. > I noticed that this is even slower but it makes the driver more clean and > allows to support both I2C and SPI (untested but will include it as a WIP). I wouldn't have expected regmap to add huge overhead relative to I2C, partly predicated on I2C being rather slow itself. There will be some overhead for concurrency protection and data marshalling but for I2C clocked at normal speeds it's surprising. --6nCHMM5kfVPLymNn Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmICibYACgkQJNaLcl1U h9AOugf/QJOPSSqlU4nYtDxke7z0DHEFzbA063OycyGY8coF3lZCkjrBvoV2zp5r gBY8Wdmv00psAkmZE7Pg3o8IZhaBn9mZ7+u/GZ0/Rzv7P+oNScm9ixRfPzOVAw5n 8ipOUBx2JYFmxMaYKsahkKl/IMSZ7w14roD+GnSHomyk1yK47L+7+ILdJdzC9Gg4 0rDNz+IF+tKQu4SrwyteAmwy0a3ufos9kj+zOH61iVOv4388BuSnoUCa0ADUCGMb n7MkSDMlJwuTJkX3sS5jJeJdi0AP+uuPwUa73zAAq3FDi7Zn3wjnRlEHP+QNa3B/ yQIr2nXx8Oy5WWWQc8CPGM7d4u+3EQ== =0FAN -----END PGP SIGNATURE----- --6nCHMM5kfVPLymNn--