From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.16]) (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 C7AA312EBE4; Thu, 15 Feb 2024 12:50:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708001417; cv=none; b=EJ8JzGHd4cLUcQDHcqwX/+enpZTQT+/gRwfrzSvlwto/2AcZzBusSlgc67CYCWG7w4np6xHh9T7fUQbCRmJtpd4PZ1bXMSX0t8/+ylu7SAP7GO/zsZgAJpzEp2RtXS16ZrPCqwW+1YMNQSfrAKKjR5O1NzxRZ7jxuS1qEYH2WaY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708001417; c=relaxed/simple; bh=nBIC9Bm1TLQ17m0KlQHQyvQ35lnC216nQhZJl1gxfNw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=c8KLhkxC/o8Xl5lS8S3JFX+kwh7WlfFEQ7Xo7eMeOPvzDY3OBZxk544RqJJZOZXh42vdB99bXg8c0Cmh2atkhi8sucDkhZ2JXLaKcUkhR7sNS44SFiM89WHvOARaWpUx2pZ3j1SEok3d7WK97o4YjM8pzuIcM6Xm8qiMku0va80= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=QrdIVAfe; arc=none smtp.client-ip=198.175.65.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="QrdIVAfe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708001414; x=1739537414; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=nBIC9Bm1TLQ17m0KlQHQyvQ35lnC216nQhZJl1gxfNw=; b=QrdIVAfeEpNcfSpVe5gRd8Wzk4EZrcJSbSK37HNyllaN0BDXr8CpUAMr AOt/SiFhfP4jTbej1ZDUGrANgfAYkvXDHpsokpXPkF7FcFJcDbrIXmY83 RBY8+G4+Ia6FZBw5ZEWsR3IG7FNRgZZdNpkufPOE2pBg1s++wkd1VzTsE 3l1tS2rkWz1GcDG1BC0AjTtLUqFarx17FOnFS7PJLzO2BvL2pVp8mjAdf KIDbKQOta+QOhZf/BeA4pu1Gw2T4Rdqun1pdh1lJoteH0ibnz2uSfu9Qc bLE70RF/l3ZCCVResLLH1hngf2KHN4o5d9d+OXaVP9MbycCPzOWBxvVua Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10984"; a="2228243" X-IronPort-AV: E=Sophos;i="6.06,161,1705392000"; d="scan'208";a="2228243" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Feb 2024 04:50:13 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.06,161,1705392000"; d="scan'208";a="3869490" Received: from turnipsi.fi.intel.com (HELO kekkonen.fi.intel.com) ([10.237.72.44]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Feb 2024 04:50:13 -0800 Received: from kekkonen.localdomain (localhost [127.0.0.1]) by kekkonen.fi.intel.com (Postfix) with SMTP id D849211F871; Thu, 15 Feb 2024 14:50:09 +0200 (EET) Date: Thu, 15 Feb 2024 12:50:09 +0000 From: Sakari Ailus To: Umang Jain Cc: Matthias Fend , Kieran Bingham , linux-media@vger.kernel.org, Mauro Carvalho Chehab , open list Subject: Re: [PATCH v2 1/5] media: i2c: imx335: Drop setting of 0x3a00 register Message-ID: References: <20240131055208.170934-1-umang.jain@ideasonboard.com> <20240131055208.170934-2-umang.jain@ideasonboard.com> <170669477439.1011926.18210850208916698098@ping.linuxembedded.co.uk> <8bc8bf66-cde9-16c4-e8bd-389940ceeeb6@ideasonboard.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8bc8bf66-cde9-16c4-e8bd-389940ceeeb6@ideasonboard.com> Hi folks, On Wed, Feb 07, 2024 at 09:51:32AM +0530, Umang Jain wrote: > 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. Very interesting case indeed. Please elaborate this a little in the commit message, but the message shouldn't be that because the register is marked rewerved, it shouldn't be written (it's a commonplace when it comes to sensors :(). -- Regards, Sakari Ailus