CMSIS framework: setup to use drivers

Hi, I have set up this project:
[env:blackpill_f401cc]
platform = ststm32
board = blackpill_f401cc
framework = cmsis
build_flags =
-DSTM32F401xC

and would like to use the i2c. I expected to have to include “Driver_i2c.h”, but the header is not found. Looking into platformIO files, it seems the headers from home_folder.platformio\packages\framework-cmsis-stm32f4 are accessible, but not the ones from home_folder.platformio\packages\framework-cmsis where all the drivers are.

Should I just manually add the path so that the driver can be found? Or is there a configuration I am missing in my config file for the project?

Looking at the header, I saw a USE_HAL_DRIVER as well, but then it complains about finding stm32f4xx_hal.h (that would be in home_folder.platformio\packages\framework-arduinoststm32\system\Drivers\STM32F4xx_HAL_Driver\Inc, so the problem is the same).

Thank you