From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 26833CA101C for ; Thu, 4 Sep 2025 19:53:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6Exz4Qv14UGEN5VZBKDBNQpwpza7/Lwt+1RtIFpWka4=; b=j54V5b80NhcpYRjmGQBSID861K AOz5nP9Sg7cTNhiUrqrLmI8jFyVXr6ggAxB8eOu19Ln95i6PxaGvtviDeJu+q2Yzn7dmEIAVwkrLL gs09m7K8flLOC37X7aPADA65gK6IYg+kJzlUk0jIdxkljqYER459IdVCCGwxqxWD9iUjRj2p6zC4u X3llUILcvd5Qq3a4A8Aj59aUaFxdOOR+aS72zWxzPx8JUTZSkzQMMA25BaiCEEbFFVAjM3Y/QbOeM yyZv9oc861lGCeotwd6mjA4AF0UCLmlsH8MqHLjASZKVvommPJoX+BktomYSeol1kQRdBM9oFzPTJ eZo40EYg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uuG11-0000000E3RQ-49MP; Thu, 04 Sep 2025 19:53:04 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uuBYw-0000000CQmu-2zLP for linux-arm-kernel@lists.infradead.org; Thu, 04 Sep 2025 15:07:47 +0000 Received: from pendragon.ideasonboard.com (230.215-178-91.adsl-dyn.isp.belgacom.be [91.178.215.230]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id 659D6F09; Thu, 4 Sep 2025 17:06:35 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1756998395; bh=fS0p2XvoEODSzfsL/y2SRg6kik4BTTH3iloa52I6Zwg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WkUjzkdazSd/Ab/viLMONgDttbk+IxhhaO8VT3lz6l273uWHfZ2k4lX1AywQrsQ7I T6O6MDjd2YlzTTZzuXizAuJ11xcf/4fpl4UVbAZQ6p51dRYPMQcIDf+cc5DbSKu2Uv PvRGlGgjqW55TCQynCJ43FPkqb9AXkY00JcMFEbw= Date: Thu, 4 Sep 2025 17:07:23 +0200 From: Laurent Pinchart To: Sakari Ailus Cc: Isaac Scott , rmfrfs@gmail.com, martink@posteo.de, kernel@puri.sm, mchehab@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-media@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, hverkuil@kernel.org, nicolas.dufresne@collabora.com, tomi.valkeinen@ideasonboard.com, jonas@kwiboo.se, dan.scally+renesas@ideasonboard.com, m.szyprowski@samsung.com, mehdi.djait@linux.intel.com, niklas.soderlund+renesas@ragnatech.se Subject: Re: [PATCH v2 1/3] media: v4l: Add helper to get number of active lanes via a pad Message-ID: <20250904150723.GC6174@pendragon.ideasonboard.com> References: <20250903102243.1563527-1-isaac.scott@ideasonboard.com> <20250903102243.1563527-2-isaac.scott@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250904_080746_890972_67F30D78 X-CRM114-Status: GOOD ( 27.24 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Sep 04, 2025 at 11:44:49AM +0300, Sakari Ailus wrote: > On Wed, Sep 03, 2025 at 11:22:40AM +0100, Isaac Scott wrote: > > Sometimes, users will not use all of the MIPI CSI 2 lanes available when > > connecting to the MIPI CSI receiver of their device. Add a helper > > function that checks the mbus_config for the device driver to allow > > users to define the number of active data lanes through the > > get_mbus_config op. > > > > If the driver does not implement this op, fall back to using the number > > of data lanes specified in device tree. > > > > Signed-off-by: Isaac Scott > > --- > > drivers/media/v4l2-core/v4l2-common.c | 25 +++++++++++++++++++++++++ > > include/media/v4l2-common.h | 1 + > > 2 files changed, 26 insertions(+) > > > > diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c > > index 6e585bc76367..8683107b3704 100644 > > --- a/drivers/media/v4l2-core/v4l2-common.c > > +++ b/drivers/media/v4l2-core/v4l2-common.c > > @@ -571,6 +571,31 @@ s64 __v4l2_get_link_freq_pad(struct media_pad *pad, unsigned int mul, > > return __v4l2_get_link_freq_ctrl(sd->ctrl_handler, mul, div); > > } > > EXPORT_SYMBOL_GPL(__v4l2_get_link_freq_pad); > > + > > +unsigned int v4l2_get_active_data_lanes(const struct media_pad *pad, unsigned int dt_lanes) > > This line would benefit from being wrapped. I'd also rename the dt_lanes parameter to max_data_lanes. "dt" sounds like data type. > > +{ > > + struct v4l2_mbus_config mbus_config = {}; > > + struct v4l2_subdev *sd; > > + unsigned int lanes; > > + int ret; > > + > > + sd = media_entity_to_v4l2_subdev(pad->entity); > > + ret = v4l2_subdev_call(sd, pad, get_mbus_config, pad->index, > > + &mbus_config); > > + if (ret < 0 && ret != -ENOIOCTLCMD) > > + return ret; > > + > > + if (!mbus_config.bus.mipi_csi2.num_data_lanes) > > + return dt_lanes; > > + > > + lanes = mbus_config.bus.mipi_csi2.num_data_lanes; > > + > > + if (lanes < 0 || lanes > dt_lanes) > > lanes is unsigned int so no need to check for less than 0. > > I might just not use a local variable for this, up to you. > A debug message would also be nice. > > + return -EINVAL; > > + > > + return lanes; > > +} > > +EXPORT_SYMBOL_GPL(v4l2_get_active_data_lanes); > > #endif /* CONFIG_MEDIA_CONTROLLER */ > > > > /* > > diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h > > index 0a43f56578bc..3f8937260c76 100644 > > --- a/include/media/v4l2-common.h > > +++ b/include/media/v4l2-common.h > > @@ -584,6 +584,7 @@ int v4l2_fill_pixfmt_mp(struct v4l2_pix_format_mplane *pixfmt, u32 pixelformat, > > (pad, mul, div) > > s64 __v4l2_get_link_freq_pad(struct media_pad *pad, unsigned int mul, > > unsigned int div); > > Some kernel-doc documentation would be nice. > > > +unsigned int v4l2_get_active_data_lanes(const struct media_pad *pad, unsigned int dt_lanes); > > Please wrap this, too. > > > #else > > #define v4l2_get_link_freq(handler, mul, div) \ > > __v4l2_get_link_freq_ctrl(handler, mul, div) -- Regards, Laurent Pinchart