In reading about the STM32G4 family, someplace on the STmicro website, this introductory page: https://www.st.com/en/microcontrollers-microprocessors/stm32g4-series.html suggests that there's a "high degree of compatibility" with the stm32f3 series. I opened the datasheet for one of the stm32f3 parts we support side-by-side with a datasheet for one of the stm32g4, and just scrolling through them, it seems the g4 has a lot more in terms of peripherals, including a high resolution timer (HRTIM), more analog, more communication, various math accelerators...
Most STM32's, certainly F4, have HRTIM. Large number of peripherals is not a big issue; the issue is if the IP is the same for a give instance of the peripheral.
The F3 is not a good point of comparison. It is like the F1 with a Cortex-M4. There will be a lot of differences compared to any contemporary parts. Compare instead with one of the F4's. I bet you find they are not so different.
There are differences in STM32 peripherals already in arch/arm/src/stm32. If only a couple of peripherals differ, then they can still cohabitate.
STM32L1 is supported in that directory and, in that case, I think it was a mistake. The L1 is far too different from the other members supported there (F1, F2, F3, F4). If I had it to do over, I would put L1, F1+F3, and L2+L4 in three directories. That is, I admit, my fault. I did all of those ports (at least initially) except for the L1.
If that were the case, my bet is the the G4 would belong with the F4. Greg
