/* Enable Peripheral Clock in running mode. 
Enable the clock on particular peripheral. */
void rcc_periph_clock_enable(enum rcc_periph_clken clken)
/* Enable Peripheral Clock in running mode. 
Enable the clock on particular peripheral. */
void rcc_periph_clock_enable(enum rcc_periph_clken clken)
{
	_RCC_REG(clken) |= _RCC_BIT(clken);
}