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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 35174C2BA1E for ; Mon, 6 Apr 2020 17:12:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0560C249CB for ; Mon, 6 Apr 2020 17:12:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YFFDLodF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729810AbgDFRMQ (ORCPT ); Mon, 6 Apr 2020 13:12:16 -0400 Received: from mail-oi1-f194.google.com ([209.85.167.194]:38991 "EHLO mail-oi1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726546AbgDFRMP (ORCPT ); Mon, 6 Apr 2020 13:12:15 -0400 Received: by mail-oi1-f194.google.com with SMTP id d63so13741086oig.6; Mon, 06 Apr 2020 10:12:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=zPvT9nYNJKIlI18d6CVFeb9HSS66c5aP1HzV/cwJ2iA=; b=YFFDLodFgLBNXipDdFrKkNe5KdfTMuCuUWZy9SOzDynX4/zoxOV+WL+e0NBF5wHS7m K2xlX4c+mLFB9R0QcvfqTnPOmVGKFzWOkG0iWwmF5LCzw0E9UWVqly7Dk1SprNmYgm+h JHYWexqjTq7egHo0iQyTN6kM6LF95CTs376RuckrF25VCJ2Z1rqm1kddE2D/SyXjf2bG DokPYV1pM8Hf5N2wOszDExe9/Qod7xhRTogKLDusnPpPe3+MMRPS2qVMiHqhYwcbAfjI kK+ER38azeo+YgVLCUzXCojrerc6K8VZ5veCSkvCLyJ+ADzkhjmedRaVE1hz86ekYpsN PL9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=zPvT9nYNJKIlI18d6CVFeb9HSS66c5aP1HzV/cwJ2iA=; b=XHD/EQtuB6l1mpYAoLchMhtGrfN9jIs3gafm9TLjdWPF6cCTMSQmG+z46LF0gtmOhW RfghgGXw7WCS//wWwOUqNXIc+6HBmyPJztXItLjDn8d9CvbU9/p81rIc0pnw682D7RiP 7yQeNU6A8lDFxZoCiekRLbPdcHJuAEzuNBKV7bJJEzXR4+thE5JlkmyFNj7VfFj34lTx OYCrrMO14xpW7Cw4PTlBJrSvqOwOhxjgfZ0FU0KOPUeSlSvB1lIFeJSW+OWd9s+ksie5 tSReErlLEAKy7yTK0Vh3Tvxd21rQKS8T7Y16uMljJXlsh+cgjqp2Mg4/jQPGvgm/iHmY 3LmQ== X-Gm-Message-State: AGi0PubxSB14wqRKoZ2JMmy0VBcWcLByswcubi3jZL/bMdBQ405bsYj1 iqcTX+8SjRfrOYtZADp962x1nQC4Pz84bU5YM8c= X-Google-Smtp-Source: APiQypKEN2WUc7C67Si85BMK8Rs/ssPmf30vW/UZKNuRyXpHzIcqTCLUJHaY3Of9rWarp68OvvmFfK4r3rsGvhQ8uHk= X-Received: by 2002:aca:5d83:: with SMTP id r125mr304838oib.8.1586193134784; Mon, 06 Apr 2020 10:12:14 -0700 (PDT) MIME-Version: 1.0 References: <1586191361-16598-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com> <1586191361-16598-3-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com> <20200406165108.GA7646@kekkonen.localdomain> In-Reply-To: <20200406165108.GA7646@kekkonen.localdomain> From: "Lad, Prabhakar" Date: Mon, 6 Apr 2020 18:11:48 +0100 Message-ID: Subject: Re: [PATCH v5 2/5] media: i2c: ov5645: Drop reading clock-frequency dt-property To: Sakari Ailus Cc: Maxime Ripard , Lad Prabhakar , Laurent Pinchart , Mauro Carvalho Chehab , Rob Herring , Mark Rutland , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Kieran Bingham , Geert Uytterhoeven , linux-media , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , LKML , LAK Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sakari, On Mon, Apr 6, 2020 at 5:51 PM Sakari Ailus wrote: > > Hi Prabhakar, > > On Mon, Apr 06, 2020 at 05:42:38PM +0100, Lad Prabhakar wrote: > > Modes in the driver are based on xvclk frequency fixed to 24MHz, but where > > as the OV5645 sensor can support the xvclk frequency ranging from 6MHz to > > 24MHz. So instead making clock-frequency as dt-property just let the > > driver enforce the required clock frequency. > > Even if some current systems where the driver is used are using 24 MHz > clock, that doesn't mean there wouldn't be systems using another frequency > that the driver does not support right now. > > The driver really should not set the frequency unless it gets it from DT, > but I think the preferred means is to use assigned-clock-rates instead, and > not to involve the driver with setting the frequency. > > Otherwise we'll make it impossible to support other frequencies, at least > without more or less random defaults. > Ouch! my previous version of patches switched the driver for using assigned-clock-rates but I was asked to not do so [1]. [1] https://patchwork.linuxtv.org/patch/62185/ Cheers, --Prabhakar > -- > Kind regards, > > Sakari Ailus 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=-0.5 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 9890DC2BA80 for ; Mon, 6 Apr 2020 17:12:18 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 69165249CB for ; Mon, 6 Apr 2020 17:12:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="KbO1rL2l"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YFFDLodF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 69165249CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=qlqGP7L25bbbwA5CbdSBQI3yjVh18UngmRVgn8htTGI=; b=KbO1rL2ltGluaJ 66Q3xIX03DH1CTKQoQUVwPfCnEU1zyUScjNsVEGllVo2lV97PeFR+VGqeOv+3dQ1C26ymVNy6wQbS eV8TRFWhZzP9Bkkr/Csg8Sw1Pv03ZnJxLuJXYTudnQkHNmDy7N1XzLVwsfS47xi+FHCYIAAisWz7i xvxqlT9FPxz0FNjc0K7xt8RtQhilCwUDES2QI+1ZwO7fS0n8PhQsggATv9NP6I65AKSO1i06FrHEg jvmqQUS2mQdsev9aRjWYEk56oyVBUeHtWj4Q9N2wCsOrwqRPY8angGgk5OYZKDttn42/i7iZTIdHW 7geM4NZ/y2xV5sLl0MPw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jLVII-0004Uo-0d; Mon, 06 Apr 2020 17:12:18 +0000 Received: from mail-oi1-x243.google.com ([2607:f8b0:4864:20::243]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jLVIF-0004UM-ND for linux-arm-kernel@lists.infradead.org; Mon, 06 Apr 2020 17:12:17 +0000 Received: by mail-oi1-x243.google.com with SMTP id d3so13787418oic.1 for ; Mon, 06 Apr 2020 10:12:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=zPvT9nYNJKIlI18d6CVFeb9HSS66c5aP1HzV/cwJ2iA=; b=YFFDLodFgLBNXipDdFrKkNe5KdfTMuCuUWZy9SOzDynX4/zoxOV+WL+e0NBF5wHS7m K2xlX4c+mLFB9R0QcvfqTnPOmVGKFzWOkG0iWwmF5LCzw0E9UWVqly7Dk1SprNmYgm+h JHYWexqjTq7egHo0iQyTN6kM6LF95CTs376RuckrF25VCJ2Z1rqm1kddE2D/SyXjf2bG DokPYV1pM8Hf5N2wOszDExe9/Qod7xhRTogKLDusnPpPe3+MMRPS2qVMiHqhYwcbAfjI kK+ER38azeo+YgVLCUzXCojrerc6K8VZ5veCSkvCLyJ+ADzkhjmedRaVE1hz86ekYpsN PL9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=zPvT9nYNJKIlI18d6CVFeb9HSS66c5aP1HzV/cwJ2iA=; b=byQMwEjl+zpDhMEfd+7wKb25wwYKJXIWt81TQw29VblY2qxz2Fi6hdbF20wdwqutQC SPFD9cIDSWJXQgkMPPkZSHs2f4Qqte2LQFr/1W4d78qTbQLOnAQWfOl8oda5+4bikXDO rs1qvQ3CoNPkqQru5rSnBpwaNRz2nDjT2890+aQ/Zo7eaPwdLSy5d4ai7AbdMISoiAPd YTJi5Xd4EGKGMq0gcI8ilezmd6hcsMqKHftZi5g+XNoVxex+dWdP9SZqDoqBUPGV2MkU n051E6ecyunsn/d+BYNot67GalbnxbaumkUklptfpZf0eFYQ0aq5MERzeiTjQEYUGVIm KFMQ== X-Gm-Message-State: AGi0PuaHgrBkfrEWCKEJtWKcNkFHUOygXtX8/nullBnnIHyAF4mLEuk2 BICwMp1tjukq/lyufBRN18EGD5aWDgSeAni0QX4= X-Google-Smtp-Source: APiQypKEN2WUc7C67Si85BMK8Rs/ssPmf30vW/UZKNuRyXpHzIcqTCLUJHaY3Of9rWarp68OvvmFfK4r3rsGvhQ8uHk= X-Received: by 2002:aca:5d83:: with SMTP id r125mr304838oib.8.1586193134784; Mon, 06 Apr 2020 10:12:14 -0700 (PDT) MIME-Version: 1.0 References: <1586191361-16598-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com> <1586191361-16598-3-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com> <20200406165108.GA7646@kekkonen.localdomain> In-Reply-To: <20200406165108.GA7646@kekkonen.localdomain> From: "Lad, Prabhakar" Date: Mon, 6 Apr 2020 18:11:48 +0100 Message-ID: Subject: Re: [PATCH v5 2/5] media: i2c: ov5645: Drop reading clock-frequency dt-property To: Sakari Ailus X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200406_101215_758213_72F4B2B3 X-CRM114-Status: GOOD ( 18.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , linux-media , Geert Uytterhoeven , Fabio Estevam , Sascha Hauer , Kieran Bingham , Lad Prabhakar , LKML , Rob Herring , Laurent Pinchart , Pengutronix Kernel Team , NXP Linux Team , Mauro Carvalho Chehab , Shawn Guo , LAK , Maxime Ripard Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Sakari, On Mon, Apr 6, 2020 at 5:51 PM Sakari Ailus wrote: > > Hi Prabhakar, > > On Mon, Apr 06, 2020 at 05:42:38PM +0100, Lad Prabhakar wrote: > > Modes in the driver are based on xvclk frequency fixed to 24MHz, but where > > as the OV5645 sensor can support the xvclk frequency ranging from 6MHz to > > 24MHz. So instead making clock-frequency as dt-property just let the > > driver enforce the required clock frequency. > > Even if some current systems where the driver is used are using 24 MHz > clock, that doesn't mean there wouldn't be systems using another frequency > that the driver does not support right now. > > The driver really should not set the frequency unless it gets it from DT, > but I think the preferred means is to use assigned-clock-rates instead, and > not to involve the driver with setting the frequency. > > Otherwise we'll make it impossible to support other frequencies, at least > without more or less random defaults. > Ouch! my previous version of patches switched the driver for using assigned-clock-rates but I was asked to not do so [1]. [1] https://patchwork.linuxtv.org/patch/62185/ Cheers, --Prabhakar > -- > Kind regards, > > Sakari Ailus _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel