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 0F5672F3C30 for ; Thu, 4 Sep 2025 15:07:46 +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=1756998468; cv=none; b=TVIt9GbeGE8pjVpXwpv10abkbHccT/c3/32ggwTsa5QHdL/HwCcoqulIWPdsdO9SQQYAXjmrUq/axgYw4WTN8HFu6+N+LdTmNMb3zUBpBZYtBG9jSiS0GPI6Vw5oUAVL3UWRXIekDHWa9uiv3OZu2OSFDGcXbtfa2DOEOQTCV94= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756998468; c=relaxed/simple; bh=fS0p2XvoEODSzfsL/y2SRg6kik4BTTH3iloa52I6Zwg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rD4/C21Xz7HzZAikSNIXf2wK7l2K2GtfxrCOcQwp8y0V/t7VLUHZE/KxE+9ZNObmqQ1prlAy1cTKYnfqCQUEV2QmO68EiSwSRltoHaVmPHOnSfQxmMy1ETYQ3dnLMc9gC8mGfsYS+nNEsvdILlEyYHG+UaZyv++UHq9/whFfJxM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (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=WkUjzkda; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (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="WkUjzkda" 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> Precedence: bulk X-Mailing-List: imx@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: 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