As soon as NVIDIA support OpenCL 2.0 in their drivers, which may be this year and is technically possible, but depends on their strategy to promote CUDA. But, you can write OpenCL 1.2 code with ClojureCL and it will work on NVIDIA. Or, if you need 2.0, use AMD...
Nvidia only supports OpenCL 1.1.
They recently updated their drivers and now support OpenCL 1.2 on recent GPUs.