From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.mainlining.org (mail.mainlining.org [5.75.144.95]) (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 CEB1240FD86; Sat, 8 Aug 2026 12:42:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=5.75.144.95 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786192969; cv=none; b=c9wTgK35Uy20hoxuscjKOhhr/4/0xVNZXzQLXVfLwmo0LjNF55KGaWP5oLG1kfDMpSOSfiuX13H2NwfuxO74oxzkw7dKX5Kq5Xq20t+hBWOlhxRdE0jbE8V62X+jLTLXbN5nMBrkrNdYMArLKjvPl6mmmWVk+0bFs/RLH7caigU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786192969; c=relaxed/simple; bh=mUoCsQbdGafhK4yw2jR4QnJOvGmcxW/iciqw7nDsy4w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=q3nToAFvyTxSPkNmp16SnRKPvUI5oWuTwhKahCmqjxAor0rA/eS/jhCjw3FGesX1ckbqzU5O79O9YriAsbzduk9UwXFrFjowmQg40zeJKcdZ0JiRhPLfdsKAOj2P/RpvZlQum1mHdTbXa9otVwILk0kZmoItsCUyJJ3ltTJ4QhE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org; spf=pass smtp.mailfrom=mainlining.org; dkim=pass (2048-bit key) header.d=mainlining.org header.i=@mainlining.org header.b=p8HnxdkJ; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b=YogH5M5s; arc=none smtp.client-ip=5.75.144.95 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mainlining.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mainlining.org header.i=@mainlining.org header.b="p8HnxdkJ"; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b="YogH5M5s" DKIM-Signature: v=1; a=rsa-sha256; s=202507r; d=mainlining.org; c=relaxed/relaxed; h=From:To:Subject:Date:Message-ID; t=1786192936; bh=TjAyu7WMvcZuDZqJUV1+hYw J+wJ5yyIqrRwvxBioKoY=; b=p8HnxdkJZuyhBMDuOM4SHLcKMWv7MMm9U9+onZ5spIGd/5+Dzh rj6bF6NJ7pVtVMPCWuhkgIi00Nfb2Wu/fDtHERkQK7VbKDywsNRbpCw1mh+ADevpjpqqpO9+iCC ir5/omBAKAhQlJM0S0z3Tg2ctfkLyFRX4UWK98CPTz6ZA8cpSzhM5yG5GnRjTsnU3PmPSL5BA+0 +7LoR5jUU9wBD3jg+yZfivjogpmzja5UFvKWTHwbNxp1X/kXmhWGtBWuq6cc1lNTYK1oOvVx4aF UfyTiBV7zLXy5W0+eVzHWjuiNpXkiR1StvmiwMdysZDKIJVbIdnwAl+u0a1Fec8qTGA==; DKIM-Signature: v=1; a=ed25519-sha256; s=202507e; d=mainlining.org; c=relaxed/relaxed; h=From:To:Subject:Date:Message-ID; t=1786192936; bh=TjAyu7WMvcZuDZqJUV1+hYw J+wJ5yyIqrRwvxBioKoY=; b=YogH5M5sluQPKiHkxYCk2luSzfxl7vez0uESXE+opRQNm1l9Th JUmKPJyj+ym/5lEQQ3SKlJt8rWdEOwEWooBA==; Message-ID: Date: Sat, 8 Aug 2026 15:42:14 +0300 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFT 2/3] media: i2c: dw9719: Add DW9800W support To: Griffin Kroah-Hartman , Sakari Ailus , Luca Weiss Cc: Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , =?UTF-8?Q?Andr=C3=A9_Apitzsch?= , Daniel Scally , Bjorn Andersson , Konrad Dybcio , Eugene Lepshy , Vasiliy Doylov , Achill Gilgenast , linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht References: <20260801-dw9800w-clean-v1-0-38978de67963@mainlining.org> <20260801-dw9800w-clean-v1-2-38978de67963@mainlining.org> <3554d8d1-65f7-4556-8b99-1c03e0cdca53@fairphone.com> Content-Language: en-US From: Danila Tikhonov In-Reply-To: <3554d8d1-65f7-4556-8b99-1c03e0cdca53@fairphone.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Griffin, Sakari, Thank you for the clarification. On 07/08/2026 17:30, Griffin Kroah-Hartman wrote: > Hello Sakari, Danilla, > > On 05/08/2026 13:29, Sakari Ailus wrote: >> Hi Danila, Griffin, >> >> On Tue, Aug 04, 2026 at 09:27:01PM +0300, Danila Tikhonov wrote: >>> Hi Sakari, >>> >>> Thank you for your comment. >>> >>> On 04/08/2026 11:40, Sakari Ailus wrote: >>>> Hi Danila, >>>> >>>> Thank you for the patch. >>>> >>>> On Sat, Aug 01, 2026 at 09:04:15PM +0300, Danila Tikhonov wrote: >>>>> The DW9800W uses the same chip ID and register layout as the DW9800K, >>>>> but requires different default VCM frequency value. >>>> Is this a real difference between the two models or what fits for the >>>> attached lens? Too bad the datasheet isn't publicly available. :-( >>>> >>>> At least the differing default and constraints for >>>> dongwoon,vcm-prescale >>>> needs to be documented in bindings. >>> I share your skepticism and have essentially the same concerns. Since I >>> do not have the DW9800K datasheet, I cannot say with certainty how it >>> differs from the DW9800W. >> Indeed. The limits should have been added for dw9800k, too, but I >> guess I >> missed this in review. :-\ >> >>> In particular, the parameter referred to as the VCM frequency in the >>> driver is used to derive the SACT value. For the DW9800W, SACT[5:0] >>> defines the actuator resonance period in SAC mode and the one-step >>> period in LSC mode. The datasheet gives the corresponding formulas as: >>> - tVIB = 6.3 ms + SACT * 0.1 ms >>> - LSC 1-step period = 252 µs + SACT * 4 µs >>> >>> Therefore, the default value may differ between the DW9800K and DW9800W >>> if the formulas or timing characteristics used to calculate SACT are >>> different. >> Griffin, would you be able to comment this? > > After checking on my side, DW9800W and K are almost identical in both > structure > and register values, including how tVIB and tLSC are calculated, > DW9800K has an extra > register that can change the output current to 130mA but we don't ever > use that. > > We didn't have a datasheet when working on the DW9800k so we had to go > off of > the downstream driver during runtime to get our register values. The > datasheet is a > much more reliable source to be using for this instead. > > My colleague has already identified ways to fix the bindings, which we > will > tackle ourselves. > I'm glad you were able to clarify the situation, as this should help us handle both IC variants correctly. >> Another matter: the comment on dw9800k says there's no device ID. So is >> there a device ID that wasn't just checked earlier or is there really no >> device ID? > > Indeed, it turns out the DW9800K DOES have an info register, which > should be > 0xEB, that's on us for not updating it after we received more > documentation. > Given this, and assuming everyone agrees, I think it would make sense for me to leave the DW9800K untouched in the next version of this patch series. Since it turns out that the DW9800K has a different Chip ID, you can fix the Chip ID check for it separately based on the information you have. One point is still unclear to me, though: is the default VCM frequency the same for both ICs, or does it differ between them? > Thanks for drawing our attention to this! Nice patch. > > Griffin > --- Best regards, Danila