[PATCH 0/4] media: platform: Add Aspeed Video Engine driver

Eddie James eajames at linux.vnet.ibm.com
Thu Aug 30 07:09:29 AEST 2018

The Video Engine (VE) embedded in the Aspeed AST2400 and AST2500 SOCs
can capture and compress video data from digital or analog sources. With
the Aspeed chip acting as a service processor, the Video Engine can
capture the host processor graphics output.

This series adds a V4L2 driver for the VE, providing a read() interface
only. The driver triggers the hardware to capture the host graphics output
and compress it to JPEG format.

Testing on an AST2500 determined that the videobuf/streaming/mmap interface
was significantly slower than the simple read() interface, so I have not
included the streaming part.

It's also possible to use an automatic mode for the VE such that
re-triggering the HW every frame isn't necessary. However this wasn't
reliable on the AST2400, and probably used more CPU anyway due to excessive
interrupts. It was approximately 15% faster.

The series also adds the necessary parent clock definitions to the Aspeed
clock driver, with both a mux and clock divider.

Eddie James (4):
  clock: aspeed: Add VIDEO reset index definition
  clock: aspeed: Setup video engine clocking
  dt-bindings: media: Add Aspeed Video Engine binding documentation
  media: platform: Add Aspeed Video Engine driver

 .../devicetree/bindings/media/aspeed-video.txt     |   23 +
 drivers/clk/clk-aspeed.c                           |   41 +-
 drivers/media/platform/Kconfig                     |    8 +
 drivers/media/platform/Makefile                    |    1 +
 drivers/media/platform/aspeed-video.c              | 1307 ++++++++++++++++++++
 include/dt-bindings/clock/aspeed-clock.h           |    1 +
 6 files changed, 1379 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/media/aspeed-video.txt
 create mode 100644 drivers/media/platform/aspeed-video.c


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