stm32/powerctrl: Don't configure clocks if already at desired frequency.
Configuring clocks is a critical operation and is best to avoid when
possible.  If the clocks really need to be reset to the same values then
one can pass in a slightly higher value, eg Hz to get 168MHz.
@@ -128,6 +128,14 @@ STATIC uint32_t calc_apb_div(uint32_t wanted_div) {
}
int powerctrl_set_sysclk(uint32_t sysclk, uint32_t ahb, uint32_t apb1, uint32_t apb2) {
+ // Return straightaway if the clocks are already at the desired frequency
+ if (sysclk == HAL_RCC_GetSysClockFreq()
+ && ahb == HAL_RCC_GetHCLKFreq()
+ && apb1 == HAL_RCC_GetPCLK1Freq()
+ && apb2 == HAL_RCC_GetPCLK2Freq()) {
+ return 0;
+ }
+
// Default PLL parameters that give 48MHz on PLL48CK
uint32_t m = HSE_VALUE / 1000000, n = 336, p = 2, q = 7;
uint32_t sysclk_source;
