From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753526AbbIXLE4 (ORCPT ); Thu, 24 Sep 2015 07:04:56 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:52698 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752318AbbIXLEy (ORCPT ); Thu, 24 Sep 2015 07:04:54 -0400 Subject: Re: [PATCH 3/4] [resend #2] fb_ddc: Allow I2C adapters without SCL read capability To: Ondrej Zary References: <1440445048-24694-1-git-send-email-linux@rainbow-software.org> <1440445048-24694-3-git-send-email-linux@rainbow-software.org> <55E6DE7D.9060700@ti.com> <201509021404.51232.linux@rainbow-software.org> CC: Krzysztof Helt , , Kernel development list From: Tomi Valkeinen Message-ID: <5603D8CE.4070605@ti.com> Date: Thu, 24 Sep 2015 14:04:46 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <201509021404.51232.linux@rainbow-software.org> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="L57LD91dOqabooCjRJPLqO6bvx9jub87v" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --L57LD91dOqabooCjRJPLqO6bvx9jub87v Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 02/09/15 15:04, Ondrej Zary wrote: > On Wednesday 02 September 2015, Tomi Valkeinen wrote: >> On 24/08/15 22:37, Ondrej Zary wrote: >>> i2c-algo-bit allows I2C adapters without SCL read capability to work = but >>> fb_ddc_read fails to work on them. >>> >>> Fix fb_ddc_read to work with I2C adapters not capable of reading SCL.= >>> >>> Signed-off-by: Ondrej Zary >>> Acked-by: Krzysztof Helt >>> --- >>> drivers/video/fbdev/core/fb_ddc.c | 8 +++++--- >>> 1 file changed, 5 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/video/fbdev/core/fb_ddc.c >>> b/drivers/video/fbdev/core/fb_ddc.c index 94322cc..22c694a 100644 >>> --- a/drivers/video/fbdev/core/fb_ddc.c >>> +++ b/drivers/video/fbdev/core/fb_ddc.c >>> @@ -69,10 +69,11 @@ unsigned char *fb_ddc_read(struct i2c_adapter >>> *adapter) algo_data->setscl(algo_data->data, 1); >>> for (j =3D 0; j < 5; j++) { >>> msleep(10); >>> - if (algo_data->getscl(algo_data->data)) >>> + if (algo_data->getscl && >>> + algo_data->getscl(algo_data->data)) >>> break; >>> } >>> - if (j =3D=3D 5) >>> + if (algo_data->getscl && j =3D=3D 5) >>> continue; >>> >>> algo_data->setsda(algo_data->data, 0); >>> @@ -91,7 +92,8 @@ unsigned char *fb_ddc_read(struct i2c_adapter *adap= ter) >>> algo_data->setscl(algo_data->data, 1); >>> for (j =3D 0; j < 10; j++) { >>> msleep(10); >>> - if (algo_data->getscl(algo_data->data)) >>> + if (algo_data->getscl && >>> + algo_data->getscl(algo_data->data)) >>> break; >>> } >> >> Aren't both of those loops pointless if there's no getscl? >=20 > They're reduced to delays - don't know how much critical they are. I think the code gets somewhat confusing the way you did it. Maybe instead something like: if (algo_data->getscl) { the current loop & delays here; } else { msleep(25); // 25 was just a guess... } Tomi --L57LD91dOqabooCjRJPLqO6bvx9jub87v Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJWA9jOAAoJEPo9qoy8lh719q8P/RYURABH1cysuT+GH+0XFVe4 Ep3DIlZCriVjHkqp6B+Y8kF39H4sKErkaCtrJj2Rcl3eML6dGkcg3aRqv5Qfnxfg uugZ9oGD3uEroiOR7kOTVgpVrpd2KGdweoTuz6PHin2zZxrMEv4xAbRL0yrvbuZ3 FU64purfJKRaZoUE40nHXbVCqnc1LH7EQ8pRT+Nqj/Yc4s4i+mpbwFdy6ju3WTtH oD8jbQlwlC7o1Vu8o+QDllZE775kCJvwIomCmB8bP5/ur7apUc9dgeVncfNB7HJ9 MT4eQbknKVRkB558EICxUqbWt7IHPDaH1vsCf24A0Uvyv4pq0PQkbgl95ftVvmuL 7ThhMYBSc3Zi0B2ikkFL5W05UNdMMeb9KmgAxyB9b+IbxkoXs/6J9smzeT27PBYJ oBWrMKRXmuVIFyYZCCc8Q3Mcp/E6tAzeqwkigu8xbU3SQfWfp7HaE8/L0UC5MYAB pwHok6mgHB4jGH7ektTEoermxWQ9GVy271jZuOxkM//lB7Poe1AplDwg2zlufOlZ z24Lb1y+7grG45eHSOO8eAesWSFqZFIAvEGKWzGwQqK6bhfh9LY1PxeYm/UumQ6I vjhPuLHMIcdJNuOdz40g+PGkCXf4cdJTQklD2y8XT5dSAi4deH2rWqkG2sa8zG87 m9oITRnsKAiqkeRS9IHx =YDS2 -----END PGP SIGNATURE----- --L57LD91dOqabooCjRJPLqO6bvx9jub87v--