Spi::enable takes Rcc as a parameter making it impossible to enable SPI after the clocks were frozen.

[pftbest]

I think there are 2 ways to solve this

1. Remove the Rcc argument and access the register internally using unsafe. Serial::new does this.
2. Split the Rcc struct, one part which configures the clock and another part which can turn on/off the peripherals.

[hardfau1t]

this one is resolved i guess, may be its ok to close