According to a recently interview with Focus-numerique, the head of product planning at Samyang Jeong Min Shin said Samyang is planing to make some auto focus lenses for Canon EF mount and Nikon F mount. Samyang has alreday made some AF lenses for Sony full frame mirrorless cameras.
From the interview:
We started the implementation of an autofocus optical FE frame and we are adapting to of other mounts, like Canon and Nikon. We also believe in Fujifilm and Micro 4/3, but these markets are not very important
They also plan to make some AF lenses for Fujfilm X-mount and Micro 4/3 mount cameras. But they believe that these markets are not very important.