Hi M.J.
I don't now exactly what constitutes bare-metal drivers but if you are interested in industrially-proven solutions for most Kinetis (K, KL, KV, KW, KE, KEA) peripherals you can take a look at the link below.
The driver code is "maintained" for all of the various Kinetis devices so that it can be used in interrupt driven/DMA based environments (bare-metal?) using any of the well known development environments (no porting between devices or development tools needed).
Operation is also simulated (using VisualStudio and the project's own Kinetis peripheral simulator) so that the internal behavior can be easily tested and analysed, as well as complete projects tested/developed/debugged in (approx.) real-time.
With over 3'000 registered users and many developments and products in service for several years (the Kinetis package has been continuously refined since 2011) it should represent one of the most refined solutions available.
I have attached its UART driver as an example - it works for any Kinetis part and supports standard or low power UARTs - including devices with mixtures, in interrupt driven or DMA modes, as well as HW flow control or RS485 configurations.
Above the peripheral drivers it also includes fully integrated stacks (TCP/IP, USB, file system, etc.) for complete project solutions (not a collection of open source parts but everything purposely developed and maintained for the single environment).
It doesn't use code generation but can operate an any Kinetis part/board by setting maximum 3 project defines!
Regards
Mark
Kinetis: http://www.utasker.com/kinetis.html
For the complete "out-of-the-box" Kinetis experience and faster time to market
