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 B1FB71AAA24 for ; Sun, 15 Dec 2024 17:02:58 +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=1734282180; cv=none; b=T0E+HxLKr28WzR8iMq81/nlLXWBqpbOIxp3Mah4aq0k8V9Fu9Le6L9qNVy+OmV8IVQKVRv0rzEI6vyQ+WQRBPG1JFCMmrRfXke8c7CDLjA0fqvuyhbxdjzfUH0B2VvOoZHE0u5iA9PepP7YIWID94en+yJai3Bshmys8iT4Mevc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734282180; c=relaxed/simple; bh=1hSNCw4ldIrWj/f+0J4gDrZMvdGFfgyzloKyglEkduk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hSOsJOD1VQrwZcvyk/h8pHHhUk8Vb/yWbjxFvI7YZJXId/DsM3wtEC/+iul4gTSF1icFB/JqhVCsbI5uqZazt+oiVFxsisc1xl0yKGyl3nZfxQhJf+1RIKhq2nA4+sfFfK+tQs08RB5nIrxQyfLcb6RryX5t5IrMnJU2qDT3510= 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=O+lM0Auo; 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="O+lM0Auo" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 08C6799F; Sun, 15 Dec 2024 18:02:20 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1734282141; bh=1hSNCw4ldIrWj/f+0J4gDrZMvdGFfgyzloKyglEkduk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=O+lM0Auoz2joIiDo7SqrtxaYuJL2k8Q6fp/IiMLhh/qzF7N89g18uhiR8CDxiG0y/ EPRIuIyuLMzGegg8wMhvN1sYYVitxICy/daxaLlcZ1fk+5XEash9vKcg8BWqHJ0tv6 bAYjE7sIMVEJgiqI3TgDk62JYN42ZLbotJEQyP5s= Date: Sun, 15 Dec 2024 19:02:40 +0200 From: Laurent Pinchart To: Sakari Ailus Cc: Jacopo Mondi , linux-media@vger.kernel.org, hverkuil@xs4all.nl Subject: Re: [PATCH v7 3/5] media: Documentation: Update link frequency driver documentation Message-ID: <20241215170240.GH9975@pendragon.ideasonboard.com> References: <20241210075906.609490-1-sakari.ailus@linux.intel.com> <20241210075906.609490-4-sakari.ailus@linux.intel.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Fri, Dec 13, 2024 at 07:15:55AM +0000, Sakari Ailus wrote: > On Thu, Dec 12, 2024 at 05:53:53PM +0100, Jacopo Mondi wrote: > > On Tue, Dec 10, 2024 at 09:59:04AM +0200, Sakari Ailus wrote: > > > Add the get_mbus_config() as the means for conveying the link frequency > > > towards the receiver drivers. > > > > > > Signed-off-by: Sakari Ailus > > > --- > > > Documentation/driver-api/media/tx-rx.rst | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > diff --git a/Documentation/driver-api/media/tx-rx.rst b/Documentation/driver-api/media/tx-rx.rst > > > index dd09484df1d3..1430c330fd52 100644 > > > --- a/Documentation/driver-api/media/tx-rx.rst > > > +++ b/Documentation/driver-api/media/tx-rx.rst > > > @@ -49,6 +49,10 @@ Link frequency > > > The :ref:`V4L2_CID_LINK_FREQ ` control is used to tell the > > > receiver the frequency of the bus (i.e. it is not the same as the symbol rate). > > > > > > +On devices where the link frequency isn't configurable, the link_freq field of > > > +struct v4l2_mbus_config is recommended over controls for conveying the link > > > +frequency to the downstream driver in the pipeline. > > > > When read in its entirety, the paragraphs > > > > Link frequency > > ^^^^^^^^^^^^^^ > > > > The :ref:`V4L2_CID_LINK_FREQ ` control is used to tell the > > receiver the frequency of the bus (i.e. it is not the same as the symbol rate). > > > > On devices where the link frequency isn't configurable, the link_freq field of > > struct v4l2_mbus_config is recommended over controls for conveying the link > > frequency. > > > > Sounds simpler without the last 7 words. > > > > A nit and just tastes maybe > > I used: > > On devices where the link frequency isn't configurable, using the ``link_freq`` > field of struct v4l2_mbus_config is recommended over controls. Is it a recommendation for the transmitter driver or the receiver driver ? If it's a recommendation for the transmitter driver, does that mean it should not implement V4L2_CID_LINK_FREQ in that case ? How about the need to expose the link frequency to userspace when it's fixed ? I think the documentation needs further clarification to clearly explain what transmitters should do and what receivers should do. > > > > I like where this is going! > > > > Reviewed-by: Jacopo Mondi -- Regards, Laurent Pinchart