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Message-ID: <1833589.VLH7GnMWUR@diego>
Date: Wed, 30 Apr 2025 11:42:41 +0200
From: Heiko Stübner <heiko@...ech.de>
To: Mehdi Djait <mehdi.djait@...ux.intel.com>,
Maxime Chevallier <maxime.chevallier@...tlin.com>,
Théo Lebrun <theo.lebrun@...tlin.com>,
Gerald Loacker <gerald.loacker@...fvision.net>,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>, Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>,
Kever Yang <kever.yang@...k-chips.com>,
Nicolas Dufresne <nicolas.dufresne@...labora.com>,
Sebastian Reichel <sebastian.reichel@...labora.com>,
Collabora Kernel Team <kernel@...labora.com>,
Paul Kocialkowski <paulk@...-base.io>,
Alexander Shiyan <eagle.alexander923@...il.com>,
Val Packett <val@...kett.cool>, Rob Herring <robh@...nel.org>,
Philipp Zabel <p.zabel@...gutronix.de>,
Sakari Ailus <sakari.ailus@...ux.intel.com>, michael.riesch@...labora.com
Cc: linux-media@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-rockchip@...ts.infradead.org,
Michael Riesch <michael.riesch@...fvision.net>,
Michael Riesch <michael.riesch@...labora.com>
Subject:
Re: [PATCH v6 01/13] Documentation: admin-guide: media: add rockchip camera
interface
Hey Michael,
Am Mittwoch, 30. April 2025, 11:15:50 Mitteleuropäische Sommerzeit schrieb Michael Riesch via B4 Relay:
> From: Michael Riesch <michael.riesch@...labora.com>
>
> Add a document that describes the different variants of the Rockchip
> Camera Interface (CIF), their hardware layout, as well as their
> representation in the media controller centric rkcif device driver,
> which is located under drivers/media/platform/rockchip/rkcif.
>
> Signed-off-by: Michael Riesch <michael.riesch@...labora.com>
> diff --git a/Documentation/admin-guide/media/rkcif.rst b/Documentation/admin-guide/media/rkcif.rst
> new file mode 100644
> index 000000000000..f35f644a54a0
> --- /dev/null
> +++ b/Documentation/admin-guide/media/rkcif.rst
> @@ -0,0 +1,83 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=========================================
> +Rockchip Camera Interface (CIF)
> +=========================================
> +
> +Introduction
> +============
> +
> +The Rockchip Camera Interface (CIF) is featured in many Rockchip SoCs in
> +different variants.
> +The different variants are combinations of common building blocks, such as
> +
> +* INTERFACE blocks of different types, namely
> +
> + * the Digital Video Port (DVP, a parallel data interface)
> + * the interface block for the MIPI CSI-2 receiver
> +
> +* CROP units
> +
> +* MIPI CSI-2 receiver (not available on all variants): This unit is referred
> + to as MIPI CSI HOST in the Rockchip documentation.
> + Technically, it is a separate hardware block, but it is strongly coupled to
> + the CIF and therefore included here.
> +
> +* MUX units (not available on all variants) that pass the video data to an
> + image signal processor (ISP)
> +
> +* SCALE units (not available on all variants)
> +
> +* DMA engines that transfer video data into system memory using a
> + double-buffering mechanism called ping-pong mode
> +
> +* Support for four streams per INTERFACE block (not available on all
> + variants), e.g., for MIPI CSI-2 Virtual Channels (VCs)
> +
> +This document describes the different variants of the CIF, their hardware
> +layout, as well as their representation in the media controller centric rkcif
> +device driver, which is located under drivers/media/platform/rockchip/rkcif.
> +
> +Variants
> +========
> +
> +Rockchip PX30 Video Input Processor (VIP)
> +-----------------------------------------
> +
> +The PX30 Video Input Processor (VIP) features a digital video port that accepts
> +parallel video data or BT.656.
> +Since these protocols do not feature multiple streams, the VIP has one DMA
> +engine that transfers the input video data into system memory.
> +
> +The rkcif driver represents this hardware variant by exposing one V4L2 subdevice
> +(the DVP INTERFACE/CROP block) and one V4L2 device (the DVP DMA engine).
> +
> +Rockchip RK3568 Video Capture (VICAP)
> +-------------------------------------
> +
> +The RK3568 Video Capture (VICAP) unit features a digital video port and a MIPI
> +CSI-2 receiver that can receive video data independently.
> +The DVP accepts parallel video data, BT.656 and BT.1120.
> +Since the BT.1120 protocol may feature more than one stream, the RK3568 VICAP
> +DVP features four DMA engines that can capture different streams.
> +Similarly, the RK3568 VICAP MIPI CSI-2 receiver features four DMA engines to
> +handle different Virtual Channels (VCs).
> +
> +The rkcif driver represents this hardware variant by exposing up to three V4L2
> +subdevices:
> +
> +* rkcif-dvp0: INTERFACE/CROP block for the DVP
> +* rockchip-mipi-csi fdfb0000.csi: MIPI CSI-2 receiver
> +* rkcif-mipi0: INTERFACE/CROP block for the MIPI CSI-2 receiver
> +
> +and up to five V4L2 devices:
> +
> +* rkcif-dvp0-id0: The support for multiple streams on the DVP is not yet
> + implemented, as it is hard to find test hardware. Thus, this video device
> + represents the first DMA engine of the RK3568 DVP.
> +* rkcif-mipi0-id[0...3]: The four DMA engines of the RK3568 MIPI CSI-2
> + receiver. Each DMA engine can capture a certain MIPI CSI-2 Virtual Channel.
> +
> +.. kernel-figure:: rkcif-rk3568-vicap.dot
> + :alt: Topology of the RK3568 Video Capture (VICAP) unit
> + :align: center
in patch 6 you already have a block stating
Finally, the RK3588 VICAP unit constitutes an essential piece of the
camera interface with one DVP, six MIPI CSI-2 receivers, scale/crop
units, and a data path multiplexer (to scaler units, to ISP, ...).
so the rk3588 seems to be on the table "soonish" ;-) .
So maybe also already include it here in the description already, if there
is a next version, and your investigation is already that far along?
Otherwise a really nice (and concise) read, and made me understand the
setup somewhat nicely.
Reviewed-by: Heiko Stuebner <heiko@...ech.de>
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