Clone skywater-pdk once into a local directory, and build it, and leave it. It does not update often (basically it has never been updated; instead I just add patches in open_pdks). This has the drawback that the skywater-pdk after building takes up a lot of disk space, and then open_pdks copies (often modified) all that data to another place, taking up even more disk space. When building open_pdks with a pre-built skywater-pdk repository, use the option

--enable-sky130-pdk=_path_to_skywater_pdk_

instead of just

--enable-sky130-pdk

. If you don't provide the path, then open_pdks will clone the repo itself and do a full build. Now, to reduce the amount of time and disk space used by the skywater-pdk repository, only build the submodules that you need. In general, the "make" process is only long and hogs disk space because of the liberty format files for the digital standard cells. So make sure you initialize the primitives library and the I/O library. Then initialize the

sky130_fd_sc_hd

standard cell library, which is the most-used and most common. After that, the

sky130_fd_sc_hvl

is useful for any 3.3V logic, and

sky130_fd_sc_hs

is useful for high-speed logic---but the open source tools struggle with precision timing, so I'm not sure it's a great idea to use the high-speed logic until the tools improve a bit.

Assuming that you've taken the steps above and that all the repositories have been configured and skywater-pdk has been built, then every update should be: For magic: 'git pull', 'make', and 'sudo make install'. For skywater-pdk: probably no action needed. For open_pdks: 'git pull', 'make', and 'sudo make install'