/**
* @brief Return SYSTEM clock frequency
* @retval SYSTEM clock frequency (in Hz)
*/
uint32_t RCC_GetSystemClockFreq(void)
{
uint32_t frequency = 0U;
/* Get SYSCLK source -------------------------------------------------------*/
switch (LL_RCC_GetSysClkSource())
{
case LL_RCC_SYS_CLKSOURCE_STATUS_MSI: /* MSI used as system clock source */
frequency = __LL_RCC_CALC_MSI_FREQ(LL_RCC_MSI_GetRange());
break;
case LL_RCC_SYS_CLKSOURCE_STATUS_HSI: /* HSI used as system clock source */
frequency = HSI_VALUE;
break;
case LL_RCC_SYS_CLKSOURCE_STATUS_HSE: /* HSE used as system clock source */
frequency = HSE_VALUE;
break;
case LL_RCC_SYS_CLKSOURCE_STATUS_PLL: /* PLL used as system clock source */
frequency = RCC_PLL_GetFreqDomain_SYS();
break;
default:
frequency = __LL_RCC_CALC_MSI_FREQ(LL_RCC_MSI_GetRange());
break;
}
return frequency;
}
/*
* Unconditionally switch the system clock source to HSI.
*/
__unused
static void stm32_clock_switch_to_hsi(u32_t ahb_prescaler)
{
/* Enable HSI if not enabled */
if (LL_RCC_HSI_IsReady() != 1) {
/* Enable HSI */
LL_RCC_HSI_Enable();
while (LL_RCC_HSI_IsReady() != 1) {
/* Wait for HSI ready */
}
}
/* Set HSI as SYSCLCK source */
LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_HSI);
LL_RCC_SetAHBPrescaler(ahb_prescaler);
while (LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_HSI) {
}
}
static int stm32_clock_control_init(struct device *dev)
{
LL_UTILS_ClkInitTypeDef s_ClkInitStruct;
ARG_UNUSED(dev);
/* configure clock for AHB/APB buses */
config_bus_clk_init((LL_UTILS_ClkInitTypeDef *)&s_ClkInitStruct);
/* Some clocks would be activated by default */
config_enable_default_clocks();
#ifdef CONFIG_CLOCK_STM32_SYSCLK_SRC_PLL
LL_UTILS_PLLInitTypeDef s_PLLInitStruct;
/* configure PLL input settings */
config_pll_init(&s_PLLInitStruct);
/*
* Switch to HSI and disable the PLL before configuration.
* (Switching to HSI makes sure we have a SYSCLK source in
* case we're currently running from the PLL we're about to
* turn off and reconfigure.)
*
* Don't use s_ClkInitStruct.AHBCLKDivider as the AHB
* prescaler here. In this configuration, that's the value to
* use when the SYSCLK source is the PLL, not HSI.
*/
stm32_clock_switch_to_hsi(LL_RCC_SYSCLK_DIV_1);
LL_RCC_PLL_Disable();
#ifdef CONFIG_CLOCK_STM32_PLL_Q_DIVISOR
MODIFY_REG(RCC->PLLCFGR, RCC_PLLCFGR_PLLQ,
CONFIG_CLOCK_STM32_PLL_Q_DIVISOR
<< POSITION_VAL(RCC_PLLCFGR_PLLQ));
#endif /* CONFIG_CLOCK_STM32_PLL_Q_DIVISOR */
#ifdef CONFIG_CLOCK_STM32_PLL_SRC_MSI
/* Switch to PLL with MSI as clock source */
LL_PLL_ConfigSystemClock_MSI(&s_PLLInitStruct, &s_ClkInitStruct);
/* Disable other clocks */
LL_RCC_HSI_Disable();
LL_RCC_HSE_Disable();
#elif CONFIG_CLOCK_STM32_PLL_SRC_HSI
/* Switch to PLL with HSI as clock source */
LL_PLL_ConfigSystemClock_HSI(&s_PLLInitStruct, &s_ClkInitStruct);
/* Disable other clocks */
LL_RCC_HSE_Disable();
LL_RCC_MSI_Disable();
#elif CONFIG_CLOCK_STM32_PLL_SRC_HSE
int hse_bypass = LL_UTILS_HSEBYPASS_OFF;
#ifdef CONFIG_CLOCK_STM32_HSE_BYPASS
hse_bypass = LL_UTILS_HSEBYPASS_ON;
#endif /* CONFIG_CLOCK_STM32_HSE_BYPASS */
/* Switch to PLL with HSE as clock source */
LL_PLL_ConfigSystemClock_HSE(CONFIG_CLOCK_STM32_HSE_CLOCK, hse_bypass,
&s_PLLInitStruct,
&s_ClkInitStruct);
/* Disable other clocks */
LL_RCC_HSI_Disable();
LL_RCC_MSI_Disable();
#endif /* CONFIG_CLOCK_STM32_PLL_SRC_... */
#elif CONFIG_CLOCK_STM32_SYSCLK_SRC_HSE
/* Enable HSE if not enabled */
if (LL_RCC_HSE_IsReady() != 1) {
/* Check if need to enable HSE bypass feature or not */
#ifdef CONFIG_CLOCK_STM32_HSE_BYPASS
LL_RCC_HSE_EnableBypass();
#else
LL_RCC_HSE_DisableBypass();
#endif /* CONFIG_CLOCK_STM32_HSE_BYPASS */
/* Enable HSE */
LL_RCC_HSE_Enable();
while (LL_RCC_HSE_IsReady() != 1) {
/* Wait for HSE ready */
}
}
/* Set HSE as SYSCLCK source */
LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_HSE);
LL_RCC_SetAHBPrescaler(s_ClkInitStruct.AHBCLKDivider);
while (LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_HSE) {
}
/* Update SystemCoreClock variable */
LL_SetSystemCoreClock(__LL_RCC_CALC_HCLK_FREQ(
CONFIG_CLOCK_STM32_HSE_CLOCK,
s_ClkInitStruct.AHBCLKDivider));
/* Set APB1 & APB2 prescaler*/
LL_RCC_SetAPB1Prescaler(s_ClkInitStruct.APB1CLKDivider);
#ifndef CONFIG_SOC_SERIES_STM32F0X
LL_RCC_SetAPB2Prescaler(s_ClkInitStruct.APB2CLKDivider);
#endif /* CONFIG_SOC_SERIES_STM32F0X */
/* Set flash latency */
/* HSI used as SYSCLK, set latency to 0 */
LL_FLASH_SetLatency(LL_FLASH_LATENCY_0);
/* Disable other clocks */
LL_RCC_HSI_Disable();
LL_RCC_MSI_Disable();
LL_RCC_PLL_Disable();
#elif CONFIG_CLOCK_STM32_SYSCLK_SRC_HSI
stm32_clock_switch_to_hsi(s_ClkInitStruct.AHBCLKDivider);
/* Update SystemCoreClock variable */
LL_SetSystemCoreClock(__LL_RCC_CALC_HCLK_FREQ(HSI_VALUE,
s_ClkInitStruct.AHBCLKDivider));
/* Set APB1 & APB2 prescaler*/
LL_RCC_SetAPB1Prescaler(s_ClkInitStruct.APB1CLKDivider);
#ifndef CONFIG_SOC_SERIES_STM32F0X
LL_RCC_SetAPB2Prescaler(s_ClkInitStruct.APB2CLKDivider);
#endif /* CONFIG_SOC_SERIES_STM32F0X */
/* Set flash latency */
/* HSI used as SYSCLK, set latency to 0 */
LL_FLASH_SetLatency(LL_FLASH_LATENCY_0);
/* Disable other clocks */
LL_RCC_HSE_Disable();
LL_RCC_MSI_Disable();
LL_RCC_PLL_Disable();
#endif /* CONFIG_CLOCK_STM32_SYSCLK_SRC_... */
return 0;
}
