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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 465D8C4332D for ; Wed, 18 Mar 2020 22:42:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1236320754 for ; Wed, 18 Mar 2020 22:42:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="b7nNzbOX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727317AbgCRWmZ (ORCPT ); Wed, 18 Mar 2020 18:42:25 -0400 Received: from mail-ot1-f66.google.com ([209.85.210.66]:42704 "EHLO mail-ot1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726647AbgCRWmZ (ORCPT ); Wed, 18 Mar 2020 18:42:25 -0400 Received: by mail-ot1-f66.google.com with SMTP id a2so374194otq.9; Wed, 18 Mar 2020 15:42:24 -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:content-transfer-encoding; bh=xmDtlPZZt6AhkIa9RNZ63X94d3qxtY/pBeuqTxtM6B8=; b=b7nNzbOXPtnvlE3gG1PJ0B6/TDG5+2bsj66N8oWRaWt+djk+gNRA8ueaW1TI6ofTIi Dv3DBijbD4E6cWOZT9jT7J2AjcCLp7qxEdmfvs35qp8VSBkLgeuD7+FdXReOQHsFlulT tFICkBCaM3fwRoF8rlvtkXP6Jgt0PQIxVv0vzYdfigRS+BQVKMCSxh9/JIDU4vpW7wTk Lv+O5O31N0BTBOeJVK60H5HnMazVMh1LWfXvZisI5fNIw4fuM8B9IM0DWcgt2K6npEJS MenqtwxHDFLS3kjlniGTDeld7jBtod/fnDZiAm6H9yD9AvqFuY6Pz+akI9ujCi6cNBKo Sc5A== 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:content-transfer-encoding; bh=xmDtlPZZt6AhkIa9RNZ63X94d3qxtY/pBeuqTxtM6B8=; b=cCgpZz7yBYArzXHINuwD4MoJtaycC9ukp53GHLXTomwEB0ZWgr7lF93lhJYGr+alQy 6jQBtxh2+U0xNfh8TV57wVhmZY3t4A/cPB8K/xL87tWO/TpkAlrKNaTGHVMRkYoerDOs mN1dVCbpMKh/lis75fghfbSe0Z6wEB+B9TPds8Y2DTKNSvcT/RLXySLp2N3nN3KAH4Ps UH1xHYjbSLjAgreWqx5paaNtma9rs66rM3r//uLq82DIVdG3Rl2ORi1WhQ7/Gx7Xatrc rPn6yTGQLmCzPTy/U8fet/JLyFk3LACF36t8/+5ShDKaxajo/M/4c5ggH6LX1WfABDZW Y8LA== X-Gm-Message-State: ANhLgQ2jXkJmWqkjg6X7/gRWUnt6NkC8ZsgRHMMKNi1RwfQ/jVToMFd/ qa9RSqGJm0igCc9InI+ZK93EEr31gHIXjpZ+pZc= X-Google-Smtp-Source: ADFU+vsvjgAClOIMqrGGIb7SpXqS1gb1iFF33qVcEpJgyK0wGZvK+9LgyP8Z7Vpzi0hvGvTCOziEP0Qb1UkSCWhgSCQ= X-Received: by 2002:a9d:6ac6:: with SMTP id m6mr6155284otq.198.1584571343441; Wed, 18 Mar 2020 15:42:23 -0700 (PDT) MIME-Version: 1.0 References: <1584133954-6953-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com> <1584133954-6953-4-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com> <20200313212345.GM4751@pendragon.ideasonboard.com> In-Reply-To: From: "Lad, Prabhakar" Date: Wed, 18 Mar 2020 22:41:57 +0000 Message-ID: Subject: Re: [PATCH v3 3/4] media: i2c: ov5645: Set maximum leverage of external clock frequency to 24480000 To: Laurent Pinchart Cc: Mark Rutland , "devicetree@vger.kernel.org" , Fabio Estevam , Sakari Ailus , Ezequiel Garcia , Prabhakar Mahadev Lad , Sascha Hauer , Magnus Damm , "linux-kernel@vger.kernel.org" , "linux-renesas-soc@vger.kernel.org" , Rob Herring , Geert Uytterhoeven , NXP Linux Team , Pengutronix Kernel Team , Mauro Carvalho Chehab , Shawn Guo , "linux-arm-kernel@lists.infradead.org" , "linux-media@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Laurent, On Fri, Mar 13, 2020 at 9:31 PM Prabhakar Mahadev Lad wrote: > > Hi Laurent, > > Thank you for the review. > > > -----Original Message----- > > From: Laurent Pinchart > > Sent: 13 March 2020 21:24 > > To: Prabhakar Mahadev Lad > > Cc: Mauro Carvalho Chehab ; Shawn Guo > > ; Sascha Hauer ; > > Pengutronix Kernel Team ; Rob Herring > > ; Mark Rutland ; Sakari > > Ailus ; NXP Linux Team ; > > Magnus Damm ; Ezequiel Garcia > > ; Geert Uytterhoeven ; > > devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; linux-renesas= - > > soc@vger.kernel.org; Fabio Estevam ; linux- > > media@vger.kernel.org; linux-arm-kernel@lists.infradead.org > > Subject: Re: [PATCH v3 3/4] media: i2c: ov5645: Set maximum leverage of > > external clock frequency to 24480000 > > > > Hi Prabhakar, > > > > Thank you for the patch. > > > > On Fri, Mar 13, 2020 at 09:12:33PM +0000, Lad Prabhakar wrote: > > > While testing on Renesas RZ/G2E platform, noticed the clock frequency > > > to be 24242424 as a result the probe failed. However increasing the > > > maximum leverage of external clock frequency to 24480000 fixes this > > > issue. Since this difference is small enough and is insignificant set > > > the same in the driver. > > > > > > Signed-off-by: Lad Prabhakar > lad.rj@bp.renesas.com> > > > --- > > > drivers/media/i2c/ov5645.c | 6 ++++-- > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c > > > index 4fbabf3..b49359b 100644 > > > --- a/drivers/media/i2c/ov5645.c > > > +++ b/drivers/media/i2c/ov5645.c > > > @@ -1107,8 +1107,10 @@ static int ov5645_probe(struct i2c_client *cli= ent) > > > } > > > > > > xclk_freq =3D clk_get_rate(ov5645->xclk); > > > -/* external clock must be 24MHz, allow 1% tolerance */ > > > -if (xclk_freq < 23760000 || xclk_freq > 24240000) { > > > +/* external clock must be 24MHz, allow a minimum 1% and a > > maximum of 2% > > > + * tolerance > > > > So where do these numbers come from ? I understand that 2% is what you > > need to make your clock fit in the range, but why -1%/+2% instead of - > > 2%/+2% ? And why not 2.5 or 3% ? The sensor datasheet documents the > > range of supported xvclk frequencies to be 6MHz to 54MHz. I understand > > that PLL parameters depend on the clock frequency, but could they be > > calculated instead of hardcoded, to avoid requiring an exact 24MHz inpu= t > > frequency ? > > > To be honest I don't have the datasheet for ov5645, the flyer says 6-54Mh= z but the > logs/comment says 24Mhz. > Comparing to ov5640 datasheet [1] (which I am assuming might be similar to ov5645), this change should affect the driver. [1] https://cdn.sparkfun.com/datasheets/Sensors/LightImaging/OV5640_datashe= et.pdf Cheers, --Prabhakar > Cheers, > --Prabhakar > > > > + */ > > > +if (xclk_freq < 23760000 || xclk_freq > 24480000) { > > > dev_err(dev, "external clock frequency %u is not > > supported\n", > > > xclk_freq); > > > return -EINVAL; > > > > -- > > Regards, > > > > Laurent Pinchart > > > Renesas Electronics Europe GmbH, Geschaeftsfuehrer/President: Carsten Jau= ch, Sitz der Gesellschaft/Registered office: Duesseldorf, Arcadiastrasse 10= , 40472 Duesseldorf, Germany, Handelsregister/Commercial Register: Duesseld= orf, HRB 3708 USt-IDNr./Tax identification no.: DE 119353406 WEEE-Reg.-Nr./= WEEE reg. no.: DE 14978647 > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel