[PATCH 0/4] media: platform: Add Aspeed Video Engine driver
eajames at linux.vnet.ibm.com
Sat Sep 1 05:30:02 AEST 2018
On 08/31/2018 12:56 PM, Stephen Boyd wrote:
> Quoting Eddie James (2018-08-29 14:09:29)
>> 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.
> Please let me know your merge strategy here. I can ack the clk patches
> because they look fine from high-level clk driver perspective (maybe
> Joel can take a closer look) or I can merge the patches into clk-next
> and get them into next release while the video driver gets reviewed.
Thanks for taking a look! Probably preferable to get the clk patches
into clk-next first (though Joel reviewing would be great). I just put
everything in the same set for the sake of explaining the necessity of
the clk changes.
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