From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from flow-a5-smtp.messagingengine.com (flow-a5-smtp.messagingengine.com [103.168.172.140]) (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 1D76F2BEC27 for ; Thu, 4 Sep 2025 08:33:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=103.168.172.140 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756974794; cv=none; b=ORNuGEU4dx24fPs45e5kusdGjN/WlsfyCOySho5WSyJjeQUiCXtOHdaJw2mBuWfI/+uMu0XhJKpfSJiKDLujiyLl/RRuGjjB17WG9+7cIyPvA29HXyI0ClM109El+dWS5CyLOn6JuawAqgle/Tcskl6oRfDttwN6qqGtxigDa14= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756974794; c=relaxed/simple; bh=QMc156WtoSHwoqi/fQG9Zopo7d5WjIyJWFRe9bvzkjU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=X8RGDXg8t69/EZtXkWu+JD/VE8ZX+SdbeGnhE+E2xABl3ejtvfULfglMAjm1nNe/ps7UNQYHoKdrFCUBSx1L+843eEMuNH81xCylsqosFRYKUFAiqU/SIygT4HYlpYAqFYvUUp8/9kFaHPdu9dbFbs7PciavpWfvlJwopOYR0+I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ragnatech.se; spf=pass smtp.mailfrom=ragnatech.se; dkim=pass (2048-bit key) header.d=ragnatech.se header.i=@ragnatech.se header.b=a7Oz2wp/; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=OZmivB4d; arc=none smtp.client-ip=103.168.172.140 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ragnatech.se Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ragnatech.se Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ragnatech.se header.i=@ragnatech.se header.b="a7Oz2wp/"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="OZmivB4d" Received: from phl-compute-03.internal (phl-compute-03.internal [10.202.2.43]) by mailflow.phl.internal (Postfix) with ESMTP id 22471138007E; Thu, 4 Sep 2025 04:33:10 -0400 (EDT) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-03.internal (MEProxy); Thu, 04 Sep 2025 04:33:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ragnatech.se; h= cc:cc:content-transfer-encoding:content-type:content-type:date :date:from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to; s=fm3; t=1756974790; x=1756981990; bh=Ge3LWeRDjf/4/fWFaTRcCNOOaVH7hBOVvV6LtBvwLVs=; b= a7Oz2wp/Lr6CCXTbEtXTQEqdnaTzqhuXeg5oAOW0OYoOq1/zLlt26Alb1NclkU7G AQWNVACneUSVnPLAogLUlJI4WM28+ZygiP9zvCK2KvaR1ajJVE8CuDPO+Htreelz xmPCRnIXUw6IZgZQaxS+Ei8LZWfFwC/3SjkgHYpmCAIz5u/2W+cw9B7qk4A6gfpW XD8cSQ1Vi4FFVoum1ZoBcitQwW4jiAhpMr2GKowGyDcZ+s7jpIBrkvZcGTEDwFpF rmg+lUlYJd28kq+1WC5BS0oTgWHQNWOFzZCQL6xDS7WFkRKl8wfHTRn4bb3jZ6QD ixauGULjU5XMHY0PY5fhYg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:content-type:date:date:feedback-id:feedback-id :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm1; t=1756974790; x= 1756981990; bh=Ge3LWeRDjf/4/fWFaTRcCNOOaVH7hBOVvV6LtBvwLVs=; b=O ZmivB4dwZfPVlmHBopD+QagJYu9aK0XzRL3SxwQeOZGC2hMB4If2zUlcHc6dOiQI o8K0O9QjMJ2oI2bHgfpPsDCFkGohRoYEgi+6HUwlMVimXDlBWvBDqrLppu0mk6D1 0WWKSykTDHxRCEeNyGo00zPQ4xj64H9eiJIYZDfxWof7bFTy0seHDLPQeZubzxvT Kgysk65/vgvI99FEmEQXIRJZ73AkhfnjEQFN9Eux+Zad8n3aKJYH3fIIYmCG9Gfl yl0CSRSv2ANx3TcFFGd4Pdw7ZYcQQwZT3DjN6I4amQBhD9qQ8LmL8ThRnFCsaDtA SXzkVhQHqWZU5jOr1RvxA== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtdeggdehheehucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfurfetoffkrfgpnffqhgenuceurghi lhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurh epfffhvfevuffkfhggtggugfgjsehtkeertddttdejnecuhfhrohhmpefpihhklhgrshcu ufpnuggvrhhluhhnugcuoehnihhklhgrshdrshhouggvrhhluhhnugdorhgvnhgvshgrsh esrhgrghhnrghtvggthhdrshgvqeenucggtffrrghtthgvrhhnpeefhfellefhffejgfef udfggeejlefhveehieekhfeulefgtdefueehffdtvdelieenucevlhhushhtvghrufhiii gvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehnihhklhgrshdrshhouggvrhhluhhn ugdorhgvnhgvshgrshesrhgrghhnrghtvggthhdrshgvpdhnsggprhgtphhtthhopedvvd dpmhhouggvpehsmhhtphhouhhtpdhrtghpthhtohepihhsrggrtgdrshgtohhtthesihgu vggrshhonhgsohgrrhgurdgtohhmpdhrtghpthhtoheplhgruhhrvghnthdrphhinhgthh grrhhtsehiuggvrghsohhnsghorghrugdrtghomhdprhgtphhtthhopehrmhhfrhhfshes ghhmrghilhdrtghomhdprhgtphhtthhopehmrghrthhinhhksehpohhsthgvohdruggvpd hrtghpthhtohepkhgvrhhnvghlsehpuhhrihdrshhmpdhrtghpthhtohepmhgthhgvhhgr sgeskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepshhhrgifnhhguhhosehkvghrnhgvlh drohhrghdprhgtphhtthhopehsrdhhrghuvghrsehpvghnghhuthhrohhnihigrdguvgdp rhgtphhtthhopehkvghrnhgvlhesphgvnhhguhhtrhhonhhigidruggv X-ME-Proxy: Feedback-ID: i80c9496c:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 4 Sep 2025 04:33:07 -0400 (EDT) Date: Thu, 4 Sep 2025 10:33:05 +0200 From: Niklas =?utf-8?Q?S=C3=B6derlund?= To: Isaac Scott Cc: laurent.pinchart@ideasonboard.com, 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, sakari.ailus@linux.intel.com, tomi.valkeinen@ideasonboard.com, jonas@kwiboo.se, dan.scally+renesas@ideasonboard.com, m.szyprowski@samsung.com, mehdi.djait@linux.intel.com Subject: Re: [PATCH v2 1/3] media: v4l: Add helper to get number of active lanes via a pad Message-ID: <20250904083305.GB1207681@ragnatech.se> 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 Content-Transfer-Encoding: 8bit In-Reply-To: <20250903102243.1563527-2-isaac.scott@ideasonboard.com> Hi Issac, Thanks for your work. On 2025-09-03 11:22:40 +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) > +{ > + 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; The function prototype is 'unsigned int' and here you return a signed value here. > + Maybe add a comment here that this check depends on mbus_config being zeroed at init if the call above pass with -ENOIOCTLCMD? It's not immediately clear what is going on here even tho the code is clever ;-) > + 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) > + 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); > +unsigned int v4l2_get_active_data_lanes(const struct media_pad *pad, unsigned int dt_lanes); > #else > #define v4l2_get_link_freq(handler, mul, div) \ > __v4l2_get_link_freq_ctrl(handler, mul, div) > -- > 2.43.0 > -- Kind Regards, Niklas Söderlund