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authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-13 22:36:58 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-13 22:36:58 +0300
commitcdb9d3537711939e4d8fd0de2889c966f88346eb (patch)
tree2a118e0930d3e08c6303b579e89f0df388cba4e6 /Documentation/userspace-api/media/drivers/aspeed-video.rst
parent102f9d3d455870844c47b82322c2dfc0a35eb745 (diff)
parent3178804c64ef7c8c87a53cd5bba0b2942dd64fec (diff)
downloadlinux-cdb9d3537711939e4d8fd0de2889c966f88346eb.tar.xz
Merge tag 'media/v6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab: - DVB core changes to avoid refcount troubles and UAF - DVB API/core has gained support for DVB-C2 and DVB-S2X - New sensor drivers: ov08x40, ov4689.c, st-vgxy61 and tc358746.c - Removal of an unused sensor driver: s5k4ecgx - Move microchip_csi2dc to a new directory, named after the manufacturer - Add media controller support to Microship drivers - Old Atmel/Microship drivers that don't use media controler got moved to staging - New drivers added for Renesas RZ/G2L CRU and MIPI CSI-2 support - Allwinner A31 camera sensor driver code was now split into a bridge and a separate processor driver - Added a virtual stateless decoder driver in order to test core support for stateless drivers and test userspace apps using it - removed platform-based support for ov9650, as this is not used anymore - atomisp now uses videobuf2 and supports normal mmap mode - the imx7-media-csi driver got promoted from staging - rcar-vin driver has gained support for gen3 UDS (Up Down Scaler) - most i2c drivers now use I2C .probe_new() kAPI - lots of drivers fixes, cleanups and improvements * tag 'media/v6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (544 commits) media: s5c73m3: Switch to GPIO descriptors media: i2c: s5k5baf: switch to using gpiod API media: i2c: s5k6a3: switch to using gpiod API media: imx: remove code for non-existing config IMX_GPT_ICAP media: si470x: Fix use-after-free in si470x_int_in_callback() media: staging: stkwebcam: Restore MEDIA_{USB,CAMERA}_SUPPORT dependencies media: coda: Add check for kmalloc media: coda: Add check for dcoda_iram_alloc dt-bindings: media: s5c73m3: Fix reset-gpio descriptor media: dt-bindings: allwinner: h6-vpu-g2: Add IOMMU reference property media: s5k4ecgx: Delete driver media: s5k4ecgx: Switch to GPIO descriptors media: Switch to use dev_err_probe() helper headers: Remove some left-over license text in include/uapi/linux/v4l2-* headers: Remove some left-over license text in include/uapi/linux/dvb/ media: usb: pwc-uncompress: Use flex array destination for memcpy() media: s5p-mfc: Fix to handle reference queue during finishing media: s5p-mfc: Clear workbit to handle error condition media: s5p-mfc: Fix in register read and write for H264 media: imx: Use get_mbus_config instead of parsing upstream DT endpoints ...
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+.. SPDX-License-Identifier: GPL-2.0
+
+.. include:: <isonum.txt>
+
+ASPEED video driver
+===================
+
+ASPEED Video Engine found on AST2400/2500/2600 SoC supports high performance
+video compressions with a wide range of video quality and compression ratio
+options. The adopted compressing algorithm is a modified JPEG algorithm.
+
+There are 2 types of compressions in this IP.
+
+* JPEG JFIF standard mode: for single frame and management compression
+* ASPEED proprietary mode: for multi-frame and differential compression.
+ Support 2-pass (high quality) video compression scheme (Patent pending by
+ ASPEED). Provide visually lossless video compression quality or to reduce
+ the network average loading under intranet KVM applications.
+
+VIDIOC_S_FMT can be used to choose which format you want. V4L2_PIX_FMT_JPEG
+stands for JPEG JFIF standard mode; V4L2_PIX_FMT_AJPG stands for ASPEED
+proprietary mode.
+
+More details on the ASPEED video hardware operations can be found in
+*chapter 6.2.16 KVM Video Driver* of SDK_User_Guide which available on
+AspeedTech-BMC/openbmc/releases.
+
+The ASPEED video driver implements the following driver-specific control:
+
+``V4L2_CID_ASPEED_HQ_MODE``
+---------------------------
+ Enable/Disable ASPEED's High quality mode. This is a private control
+ that can be used to enable high quality for aspeed proprietary mode.
+
+.. flat-table::
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 4
+
+ * - ``(0)``
+ - ASPEED HQ mode is disabled.
+ * - ``(1)``
+ - ASPEED HQ mode is enabled.
+
+``V4L2_CID_ASPEED_HQ_JPEG_QUALITY``
+-----------------------------------
+ Define the quality of ASPEED's High quality mode. This is a private control
+ that can be used to decide compression quality if High quality mode enabled
+ . Higher the value, better the quality and bigger the size.
+
+.. flat-table::
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 4
+
+ * - ``(1)``
+ - minimum
+ * - ``(12)``
+ - maximum
+ * - ``(1)``
+ - step
+ * - ``(1)``
+ - default
+
+**Copyright** |copy| 2022 ASPEED Technology Inc.