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 6AE45746E; Thu, 15 May 2025 13:03:51 +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=1747314233; cv=none; b=caY/Swhvp5iVpnhl5piJHDVB00vPX9GOOeXvFmRsRWEG5XsS7bN3bvmUCyGwIp6InJKYXGWB2ig4a+T0XHL3dBYBEQWeA215KwhewdKW8uCghVtdB+xhdV1FNBYcH8Clk56vOG+Hwt0UaDRUYM2BqFFCnBMlDMwnqzXEO/+92Ok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747314233; c=relaxed/simple; bh=G4w8+WYceQ0TUvOZZ7wsRh/B3jbJuEiol/rwYLXiXEs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AtWhwYNiseN4VtGMqldy5SP/tTXefhP5N8yS5kwWEb8pmWN+Dp4ewPoBOTcldzh6AmHGxixct36HuIQCDNwUVLrMPvaOFTjDoPU5P00VNKshi3iCsLPSR/fFo5xEmL/04PNEVnzu9nbON0H3G6l8rtm6wvZ4kr1CcQZdYUwVX3A= 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=AIkWM9DE; 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="AIkWM9DE" Received: from pendragon.ideasonboard.com (85-76-100-182-nat.elisa-mobile.fi [85.76.100.182]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 93E27886; Thu, 15 May 2025 15:03:32 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1747314212; bh=G4w8+WYceQ0TUvOZZ7wsRh/B3jbJuEiol/rwYLXiXEs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AIkWM9DEj9EpoWLMm9YJ2wAODIcNSamGD/ZrViLoOAnyV1UxwrOTccrVBUgYnc0rl NUzjqp+PPRKveyZzRDXYLS742D6dZmLo4YYcs28RqrZq4gHMIiRazgsp69WsxhjMDs gpTnlp1kN/hYwNTpSPdA3SIc80iJh1yopdAAkJZU= Date: Thu, 15 May 2025 15:03:40 +0200 From: Laurent Pinchart To: Sakari Ailus 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: <20250515130340.GC12492@pendragon.ideasonboard.com> References: <20250505-imx214_ccs_pll-v2-0-f50452061ff1@apitzsch.eu> <20250505-imx214_ccs_pll-v2-4-f50452061ff1@apitzsch.eu> <20250515085846.GR23592@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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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 :-) -- Regards, Laurent Pinchart