From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 147C912E47; Wed, 7 Feb 2024 04:21:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707279704; cv=none; b=aZQgkhAj5belEOLUKVukxfOh9jUHNSeOUnI85z3NjNBSH7//N4CJKtrCw+cOpC4AAPmlC3YMXjlgATL6RME1Ea40Qnpd1SBcI6aaRc3HE4rL2gf4AVEwBoxL+4Nqpe02ibQojNL9QzjBl2OY6xYE0E4jpYnUG4l28IIp8qdEiKc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707279704; c=relaxed/simple; bh=JlMYUCEGbfNjg9V4RzOWmQF7tZQ6hk2ya5k40YzeHkw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=NQS+TJmUJMyDEMp7my8ldg7Wmkgs47Az83REDCDXzLc2eyH473xer/fJqkDB0KPFWBfKlVUa39ivqpO4Vp5oOnlccuqA3wNTL5SYsCbFYvCG+9/ErtxtfJgVudrX2gKo2fjwyUwkjAYFniPHG09iNPLvtK543j4Ii1vip+7YiAQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=GDcWF9+U; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="GDcWF9+U" Received: from [192.168.1.106] (unknown [103.251.226.118]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 31FC8975; Wed, 7 Feb 2024 05:20:13 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1707279616; bh=JlMYUCEGbfNjg9V4RzOWmQF7tZQ6hk2ya5k40YzeHkw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=GDcWF9+U2EWc9jjaaqwvKt958k1WsKqHwrzJQlkCc4GdRVRipYlxm2e8lc2ArdJCq M79+HuXymzEInzm0P9Gsr1dbRdGoOGtWtHARZGFvQ3wB42FDzYLctuO688s922cR6k Sq7o8ROgd2lkIJlGBsb0TrutXzj5C4cwMxGBQHyo= Message-ID: <8bc8bf66-cde9-16c4-e8bd-389940ceeeb6@ideasonboard.com> Date: Wed, 7 Feb 2024 09:51:32 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH v2 1/5] media: i2c: imx335: Drop setting of 0x3a00 register To: Matthias Fend , Kieran Bingham , linux-media@vger.kernel.org Cc: Mauro Carvalho Chehab , open list , Sakari Ailus References: <20240131055208.170934-1-umang.jain@ideasonboard.com> <20240131055208.170934-2-umang.jain@ideasonboard.com> <170669477439.1011926.18210850208916698098@ping.linuxembedded.co.uk> Content-Language: en-US From: Umang Jain In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi, On 1/31/24 4:02 PM, Matthias Fend wrote: > Hi Kieran, > > Am 31.01.2024 um 10:52 schrieb Kieran Bingham: >> Hi Umang, >> >> + Cc: Matthias >> >> Quoting Umang Jain (2024-01-31 05:52:04) >>> Register 0x3a00 is a reserved field as per the IMX335 datasheet, >>> hence shouldn't be set by the driver. >> >> We still need to explain more about why we're dropping this register >> write, and what effects it causes. >> >> Matthias - I believe this stemmed from the work you did, and I think I >> recall that you stated this register write broke the CSI2 configuration? >> >> Can you clarify anything here for us please? > > yes, that's correct. > > Since this driver originally did not work in my setup, I came across > this register while searching for differences to my working reference > configuration. > With the default value of this register (0x00), the driver works > perfectly. With the value previously written to it by the driver > (0x01), I cannot receive any frames. > The problem may depend on the link frequency used. > I can only use and test a frequency of 445.5MHz on my hardware. Since > only link frequencies of 594MHz were supported so far, this may not > have been a problem. > > Unfortunately I do not have a description of this register, so I can > only speculate about the exact cause. Is it worth to frame the commit message around this speculation ? My setup has no effect with this register being set or not. > > ~Matthias > >> >> -- >> Kieran >> >> >>> >>> Signed-off-by: Umang Jain >>> --- >>>   drivers/media/i2c/imx335.c | 1 - >>>   1 file changed, 1 deletion(-) >>> >>> diff --git a/drivers/media/i2c/imx335.c b/drivers/media/i2c/imx335.c >>> index 7a37eb327ff4..927b4806a5d7 100644 >>> --- a/drivers/media/i2c/imx335.c >>> +++ b/drivers/media/i2c/imx335.c >>> @@ -249,7 +249,6 @@ static const struct imx335_reg >>> mode_2592x1940_regs[] = { >>>          {0x3794, 0x7a}, >>>          {0x3796, 0xa1}, >>>          {0x37b0, 0x36}, >>> -       {0x3a00, 0x01}, >>>   }; >>>     static const struct imx335_reg raw10_framefmt_regs[] = { >>> -- >>> 2.41.0 >>>