From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (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 78E381953AD; Thu, 15 May 2025 21:02:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747342943; cv=none; b=Ojc/7uAkzCl3jLLfE67aIlWGT/NqDrpNvEnJhAKrufIUKlfFbI8ikmBkZhy4+OPQkzEah/g68GxZ/3zzK50y/aiEYbSkGiNj/d4EMlPfy3+B3wmnOjHjF8eOr/AwBKSZu7zaZVrJ/qhWdZ/n/q15IIU90SXmbirFKbF4pxmDcgI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747342943; c=relaxed/simple; bh=RHt77bFv5evVuMMc+JyW0Hp/S0AcRu5oQI6stzOQhSk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=B9Rfn4zwqgR0oTTqezt9AF4zx7sNrgyB2Y22IqRF664xhtsn5p9wIHJ8mAIYvt86QmGPLvjQCpMtM+IgZBukF6i34azumGDgI9LybhBIFGVK9kByc1M3VlcLjPulg3SRbBizUsNyacV76uX4ApEEFRG578OfFh0Xf2tLrVRtksk= 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=fDnyW4Au; arc=none smtp.client-ip=192.198.163.12 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="fDnyW4Au" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1747342941; x=1778878941; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=RHt77bFv5evVuMMc+JyW0Hp/S0AcRu5oQI6stzOQhSk=; b=fDnyW4Au0E4tWsBW1LUeITZQEZvbi4N6TiTWD9OaPJllNNgvn1rThktQ 45TiLRwp/YjP6lHgYgG87Q/NC3SSRgfY1yI3MbBU0j17k42JdG/gr5+hX htYl+zhX4vEiYcm2C5llZ6VPA8tEKQ5e1PeZMq/0Ww5pe9iJfPz0P9qqv 1IpvxnmP07kvUOOX9tN7sb4IpkpKuwnW0fNUXAIgjjUyEkLRkOqh2yCLn XO15uF4vqICOniMJbIeckpjs39nTX2+upwr9YiwGP0Kw2SpwU0+8hwfh5 aIjjJNtisftR4MB5xDpQIKELWLunIQDfPbS1jTHRpnzr2b2a23kORU8UI w==; X-CSE-ConnectionGUID: XtmTXvtyR9uv/pnd6vdJlA== X-CSE-MsgGUID: ZK2CK7L5RdmdYMI8zhMOGA== X-IronPort-AV: E=McAfee;i="6700,10204,11434"; a="53104664" X-IronPort-AV: E=Sophos;i="6.15,292,1739865600"; d="scan'208";a="53104664" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 May 2025 14:02:20 -0700 X-CSE-ConnectionGUID: YopiuzxrTnyen6ZWe/Jx6w== X-CSE-MsgGUID: Uo+G6v3DQgmdb7axSkzwYw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,292,1739865600"; d="scan'208";a="169416201" Received: from pgcooper-mobl3.ger.corp.intel.com (HELO svinhufvud) ([10.245.245.59]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 May 2025 14:02:18 -0700 Date: Fri, 16 May 2025 00:02:15 +0300 From: Sakari Ailus To: Laurent Pinchart Cc: git@apitzsch.eu, Ricardo Ribalda , Mauro Carvalho Chehab , ~postmarketos/upstreaming@lists.sr.ht, phone-devel@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 4/4] media: i2c: imx214: Remove hard-coded external clock frequency Message-ID: References: <20250505-imx214_ccs_pll-v2-0-f50452061ff1@apitzsch.eu> <20250505-imx214_ccs_pll-v2-4-f50452061ff1@apitzsch.eu> <20250515085846.GR23592@pendragon.ideasonboard.com> <20250515130340.GC12492@pendragon.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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250515130340.GC12492@pendragon.ideasonboard.com> Hi Laurent, On Thu, May 15, 2025 at 03:03:40PM +0200, Laurent Pinchart wrote: > On Thu, May 15, 2025 at 02:54:54PM +0300, Sakari Ailus wrote: > > On Thu, May 15, 2025 at 10:58:46AM +0200, Laurent Pinchart wrote: > > > On Tue, May 06, 2025 at 08:24:03AM +0000, Sakari Ailus wrote: > > > > On Mon, May 05, 2025 at 11:05:56PM +0200, André Apitzsch via B4 Relay wrote: > > > > > From: André Apitzsch > > > > > > > > > > Instead rely on the rate set on the clock (using assigned-clock-rates > > > > > etc.) > > > > > > > > > > Signed-off-by: André Apitzsch > > > > > --- > > > > > drivers/media/i2c/imx214.c | 6 ------ > > > > > 1 file changed, 6 deletions(-) > > > > > > > > > > diff --git a/drivers/media/i2c/imx214.c b/drivers/media/i2c/imx214.c > > > > > index 9e9be47394ec768a5b34d44b06b5bbb0988da5a1..c12996e294dccebb18c608254f1e0d14dc064423 100644 > > > > > --- a/drivers/media/i2c/imx214.c > > > > > +++ b/drivers/media/i2c/imx214.c > > > > > @@ -32,7 +32,6 @@ > > > > > > > > > > #define IMX214_REG_FAST_STANDBY_CTRL CCI_REG8(0x0106) > > > > > > > > > > -#define IMX214_DEFAULT_CLK_FREQ 24000000 > > > > > #define IMX214_DEFAULT_LINK_FREQ 600000000 > > > > > /* Keep wrong link frequency for backward compatibility */ > > > > > #define IMX214_DEFAULT_LINK_FREQ_LEGACY 480000000 > > > > > @@ -1405,11 +1404,6 @@ static int imx214_probe(struct i2c_client *client) > > > > > return dev_err_probe(dev, PTR_ERR(imx214->xclk), > > > > > "failed to get xclk\n"); > > > > > > > > > > - ret = clk_set_rate(imx214->xclk, IMX214_DEFAULT_CLK_FREQ); > > > > > - if (ret) > > > > > - return dev_err_probe(dev, ret, > > > > > - "failed to set xclk frequency\n"); > > > > > - > > > > > > > > Oops. I missed this is what the driver was doing already. Indeed, this is > > > > one of the historic sensor drivers that do set the frequency in DT systems. > > > > > > > > The driver never used the clock-frequency property and instead used a fixed > > > > frequency. Changing the behaviour now could be problematic. > > > > > > > > There are options here that I think we could do: > > > > > > > > 1) use your v1 patch (4) which uses "clock-frequency" if it exists and > > > > otherwise uses the default, fixed frequency or > > > > > > > > 2) set the frequency only if the "clock-frequency" property exists. The DT > > > > currently requires clock-frequency and the YAML conversion was done in 2020 > > > > whereas the driver is from 2018. If we do this, the clock-frequency should > > > > be deprecated (or even removed from bingings). > > > > > > > > I wonder what others think. Cc'd Laurent in any case. > > > > > > Maybe I'm missing something, but I don't really see the issue here. The > > > clock-frequency DT property is currently ignored, and this patch doesn't > > > change that situation, does it ? > > > > > > The change of behaviour here is related to the assigned-clock-rates > > > property. If that property is specified today, it will set the clock > > > rate, and the driver will override it to 24MHz right after. With this > > > patch, the clock rate won't be overridden. I think the risk of > > > regression is very low here, as I don't expect systems to set > > > assigned-clock-rates in DT to a value different than 24MHz and expect > > > the driver to override it. > > > > If the DTS had assigned-clock-rates set correctly, then yes. How much can > > we trust the older DTS did have that? > > I am relatively confident that DT-based systems wouldn't have an > assigned-clock-rates property with a frequency that doesn't match > IMX214_DEFAULT_CLK_FREQ. The real question is whether or not I'm > over-confident :-) The assigned-clock stuff wasn't always there. But nowadays I guess a lot of things in practice depends on it. So I guess doing this should be fine then. -- Sakari Ailus