sksp2024-mcu/libopencm3/lib/stm32/l0/rcc.c

/** @defgroup rcc_file RCC peripheral API
 *
 * @ingroup peripheral_apis
 *
 * @brief <b>libopencm3 STM32L0xx Reset and Clock Control</b>
 *
 * @version 1.0.0
 *
 * @date November 2014
 *
 * This library supports the Reset and Clock Control System in the STM32F0xx
 * series of ARM Cortex Microcontrollers by ST Microelectronics.
 *
 * LGPL License Terms @ref lgpl_license
 */
/*
 * This file is part of the libopencm3 project.
 *
 * Copyright (C) 2014 Karl Palsson <karlp@tweak.net.au>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

/**@{*/

#include <libopencm3/cm3/assert.h>
#include <libopencm3/stm32/flash.h>
#include <libopencm3/stm32/pwr.h>
#include <libopencm3/stm32/rcc.h>

/* Set the default clock frequencies after reset. */
uint32_t rcc_ahb_frequency = 2097000;
uint32_t rcc_apb1_frequency = 2097000;
uint32_t rcc_apb2_frequency = 2097000;

void rcc_osc_on(enum rcc_osc osc)
{
	switch (osc) {
	case RCC_PLL:
		RCC_CR |= RCC_CR_PLLON;
		break;
	case RCC_MSI:
		RCC_CR |= RCC_CR_MSION;
		break;
	case RCC_HSE:
		RCC_CR |= RCC_CR_HSEON;
		break;
	case RCC_HSI48:
		RCC_CRRCR |= RCC_CRRCR_HSI48ON;
		break;
	case RCC_HSI16:
		RCC_CR |= RCC_CR_HSI16ON;
		break;
	case RCC_LSE:
		RCC_CSR |= RCC_CSR_LSEON;
		break;
	case RCC_LSI:
		RCC_CSR |= RCC_CSR_LSION;
		break;
	}
}

void rcc_osc_off(enum rcc_osc osc)
{
	switch (osc) {
	case RCC_PLL:
		RCC_CR &= ~RCC_CR_PLLON;
		break;
	case RCC_MSI:
		RCC_CR &= ~RCC_CR_MSION;
		break;
	case RCC_HSE:
		RCC_CR &= ~RCC_CR_HSEON;
		break;
	case RCC_HSI48:
		RCC_CRRCR &= ~RCC_CRRCR_HSI48ON;
		break;
	case RCC_HSI16:
		RCC_CR &= ~RCC_CR_HSI16ON;
		break;
	case RCC_LSE:
		RCC_CSR &= ~RCC_CSR_LSEON;
		break;
	case RCC_LSI:
		RCC_CSR &= ~RCC_CSR_LSION;
		break;
	}
}


/*---------------------------------------------------------------------------*/
/** @brief RCC Clear the Oscillator Ready Interrupt Flag
 *
 * Clear the interrupt flag that was set when a clock oscillator became ready
 * to use.
 *
 * @param[in] osc Oscillator ID
 */
void rcc_osc_ready_int_clear(enum rcc_osc osc)
{
	switch (osc) {
	case RCC_PLL:
		RCC_CICR |= RCC_CICR_PLLRDYC;
		break;
	case RCC_HSE:
		RCC_CICR |= RCC_CICR_HSERDYC;
		break;
	case RCC_HSI48:
		RCC_CICR |= RCC_CICR_HSI48RDYC;
		break;
	case RCC_HSI16:
		RCC_CICR |= RCC_CICR_HSI16RDYC;
		break;
	case RCC_MSI:
		RCC_CICR |= RCC_CICR_MSIRDYC;
		break;
	case RCC_LSE:
		RCC_CICR |= RCC_CICR_LSERDYC;
		break;
	case RCC_LSI:
		RCC_CICR |= RCC_CICR_LSIRDYC;
		break;
	}
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Enable the Oscillator Ready Interrupt
 *
 * @param[in] osc Oscillator ID
 */
void rcc_osc_ready_int_enable(enum rcc_osc osc)
{
	switch (osc) {
	case RCC_PLL:
		RCC_CIER |= RCC_CIER_PLLRDYIE;
		break;
	case RCC_HSE:
		RCC_CIER |= RCC_CIER_HSERDYIE;
		break;
	case RCC_HSI48:
		RCC_CIER |= RCC_CIER_HSI48RDYIE;
		break;
	case RCC_HSI16:
		RCC_CIER |= RCC_CIER_HSI16RDYIE;
		break;
	case RCC_MSI:
		RCC_CIER |= RCC_CIER_MSIRDYIE;
		break;
	case RCC_LSE:
		RCC_CIER |= RCC_CIER_LSERDYIE;
		break;
	case RCC_LSI:
		RCC_CIER |= RCC_CIER_LSIRDYIE;
		break;
	}
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Disable the Oscillator Ready Interrupt
 *
 * @param[in] osc Oscillator ID
 */
void rcc_osc_ready_int_disable(enum rcc_osc osc)
{
	switch (osc) {
	case RCC_PLL:
		RCC_CIER &= ~RCC_CIER_PLLRDYIE;
		break;
	case RCC_HSE:
		RCC_CIER &= ~RCC_CIER_HSERDYIE;
		break;
	case RCC_HSI48:
		RCC_CIER &= ~RCC_CIER_HSI48RDYIE;
		break;
	case RCC_HSI16:
		RCC_CIER &= ~RCC_CIER_HSI16RDYIE;
		break;
	case RCC_MSI:
		RCC_CIER &= ~RCC_CIER_MSIRDYIE;
		break;
	case RCC_LSE:
		RCC_CIER &= ~RCC_CIER_LSERDYIE;
		break;
	case RCC_LSI:
		RCC_CIER &= ~RCC_CIER_LSIRDYIE;
		break;
	}
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Read the Oscillator Ready Interrupt Flag
 *
 * @param[in] osc Oscillator ID
 * @returns int. Boolean value for flag set.
 */
int rcc_osc_ready_int_flag(enum rcc_osc osc)
{
	switch (osc) {
	case RCC_PLL:
		return ((RCC_CIFR & RCC_CIFR_PLLRDYF) != 0);
		break;
	case RCC_HSE:
		return ((RCC_CIFR & RCC_CIFR_HSERDYF) != 0);
		break;
	case RCC_HSI48:
		return ((RCC_CIFR & RCC_CIFR_HSI48RDYF) != 0);
		break;
	case RCC_HSI16:
		return ((RCC_CIFR & RCC_CIFR_HSI16RDYF) != 0);
		break;
	case RCC_MSI:
		return ((RCC_CIFR & RCC_CIFR_MSIRDYF) != 0);
		break;
	case RCC_LSE:
		return ((RCC_CIFR & RCC_CIFR_LSERDYF) != 0);
		break;
	case RCC_LSI:
		return ((RCC_CIFR & RCC_CIFR_LSIRDYF) != 0);
		break;
	}

	cm3_assert_not_reached();
}


bool rcc_is_osc_ready(enum rcc_osc osc)
{
	switch (osc) {
	case RCC_PLL:
		return RCC_CR & RCC_CR_PLLRDY;
	case RCC_HSE:
		return RCC_CR & RCC_CR_HSERDY;
	case RCC_HSI16:
		return RCC_CR & RCC_CR_HSI16RDY;
	case RCC_HSI48:
		return RCC_CRRCR & RCC_CRRCR_HSI48RDY;
	case RCC_MSI:
		return RCC_CR & RCC_CR_MSIRDY;
	case RCC_LSE:
		return RCC_CSR & RCC_CSR_LSERDY;
	case RCC_LSI:
		return RCC_CSR & RCC_CSR_LSIRDY;
	}
	return false;
}

void rcc_wait_for_osc_ready(enum rcc_osc osc)
{
	while (!rcc_is_osc_ready(osc));
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Set HSI48 clock source to the RC48 (CRS)
 */
void rcc_set_hsi48_source_rc48(void)
{
	RCC_CCIPR |= RCC_CCIPR_HSI48SEL;
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Set HSI48 clock source to the PLL
 */
void rcc_set_hsi48_source_pll(void)
{
	RCC_CCIPR &= ~RCC_CCIPR_HSI48SEL;
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Set the Source for the System Clock.
 *
 * @param[in] osc Oscillator ID. Only HSE, HSI16, MSI and PLL have effect.
 */

void rcc_set_sysclk_source(enum rcc_osc osc)
{
	switch (osc) {
	case RCC_PLL:
		RCC_CFGR |=  RCC_CFGR_SW_PLL;
		break;
	case RCC_HSE:
		RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW_MASK) | RCC_CFGR_SW_HSE;
		break;
	case RCC_HSI16:
		RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW_MASK) | RCC_CFGR_SW_HSI16;
		break;
	case RCC_MSI:
		RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW_MASK) | RCC_CFGR_SW_MSI;
		break;
	case RCC_HSI48:
	case RCC_LSE:
	case RCC_LSI:
		break;
	}
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Set the PLL Multiplication Factor.
 *
 * @note This only has effect when the PLL is disabled.
 *
 * @param[in] factor PLL multiplication factor @ref rcc_cfgr_pmf
 */

void rcc_set_pll_multiplier(uint32_t factor)
{
	uint32_t reg = RCC_CFGR
		       & ~(RCC_CFGR_PLLMUL_MASK << RCC_CFGR_PLLMUL_SHIFT);
	RCC_CFGR = reg | (factor << RCC_CFGR_PLLMUL_SHIFT);
}


/*---------------------------------------------------------------------------*/
/** @brief RCC Set the PLL Division Factor.
 *
 * @note This only has effect when the PLL is disabled.
 *
 * @param[in] factor PLL multiplication factor @ref rcc_cfgr_pdf
 */

void rcc_set_pll_divider(uint32_t factor)
{
	uint32_t reg = RCC_CFGR
		       & ~(RCC_CFGR_PLLDIV_MASK << RCC_CFGR_PLLDIV_SHIFT);
	RCC_CFGR = reg | (factor << RCC_CFGR_PLLDIV_SHIFT);
}

/**
 * Set the pll source.
 * @param pllsrc RCC_CFGR_PLLSRC_HSI16_CLK or RCC_CFGR_PLLSRC_HSE_CLK
 */
void rcc_set_pll_source(uint32_t pllsrc)
{
	uint32_t reg32;

	reg32 = RCC_CFGR;
	reg32 &= ~(RCC_CFGR_PLLSRC_HSE_CLK << 16);
	RCC_CFGR = (reg32 | (pllsrc<<16));
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Set the APB1 Prescale Factor.
 *
 * @note The APB1 clock frequency must not exceed 32MHz.
 *
 * @param[in] ppre APB prescale factor @ref rcc_cfgr_apb1pre
 */

void rcc_set_ppre1(uint32_t ppre)
{
	uint32_t reg = RCC_CFGR
		       & ~(RCC_CFGR_PPRE1_MASK << RCC_CFGR_PPRE1_SHIFT);
	RCC_CFGR = reg | (ppre << RCC_CFGR_PPRE1_SHIFT);
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Set the APB2 Prescale Factor.
 *
 * @note The APB2 clock frequency must not exceed 32MHz.
 *
 * @param[in] ppre APB prescale factor @ref rcc_cfgr_apb2pre
 */

void rcc_set_ppre2(uint32_t ppre)
{
	uint32_t reg = RCC_CFGR
		       & ~(RCC_CFGR_PPRE2_MASK << RCC_CFGR_PPRE2_SHIFT);
	RCC_CFGR = reg | (ppre << RCC_CFGR_PPRE2_SHIFT);
}

/*---------------------------------------------------------------------------*/
/** @brief RCC Set the AHB Prescale Factor.
 *
 * @param[in] hpre Unsigned int32. AHB prescale factor @ref rcc_cfgr_ahbpre
 */

void rcc_set_hpre(uint32_t hpre)
{
	uint32_t reg = RCC_CFGR & ~(RCC_CFGR_HPRE_MASK << RCC_CFGR_HPRE_SHIFT);
	RCC_CFGR = reg | (hpre << RCC_CFGR_HPRE_SHIFT);
}

/*---------------------------------------------------------------------------*/
/** @brief Set the range of the MSI oscillator
*
 * @param msi_range desired range @ref rcc_icscr_msirange
 */
void rcc_set_msi_range(uint32_t msi_range)
{
	uint32_t reg32 = RCC_ICSCR & ~(RCC_ICSCR_MSIRANGE_MASK << RCC_ICSCR_MSIRANGE_SHIFT);
	RCC_ICSCR = reg32 | (msi_range << RCC_ICSCR_MSIRANGE_SHIFT);
}

/*---------------------------------------------------------------------------*/
/** @brief Set the LPTIM1 clock source
*
 * @param lptim1_sel peripheral clock source @ref rcc_ccpipr_lptim1sel
 */
void rcc_set_lptim1_sel(uint32_t lptim1_sel)
{
	RCC_CCIPR &= ~(RCC_CCIPR_LPTIM1SEL_MASK << RCC_CCIPR_LPTIM1SEL_SHIFT);
	RCC_CCIPR |= (lptim1_sel << RCC_CCIPR_LPTIM1SEL_SHIFT);
}


/*---------------------------------------------------------------------------*/
/** @brief Set the LPUART1 clock source
*
 * @param lpuart1_sel periphral clock source @ref rcc_ccpipr_lpuart1sel
 */
void rcc_set_lpuart1_sel(uint32_t lpuart1_sel)
{
	RCC_CCIPR &= ~(RCC_CCIPR_LPUART1SEL_MASK << RCC_CCIPR_LPTIM1SEL_SHIFT);
	RCC_CCIPR |= (lpuart1_sel << RCC_CCIPR_LPTIM1SEL_SHIFT);
}

/*---------------------------------------------------------------------------*/
/** @brief Set the USART1 clock source
*
 * @param usart1_sel periphral clock source @ref rcc_ccpipr_usart1sel
 */
void rcc_set_usart1_sel(uint32_t usart1_sel)
{
	RCC_CCIPR &= ~(RCC_CCIPR_USART1SEL_MASK << RCC_CCIPR_USART1SEL_SHIFT);
	RCC_CCIPR |= (usart1_sel << RCC_CCIPR_USART1SEL_SHIFT);
}

/*---------------------------------------------------------------------------*/
/** @brief Set the USART2 clock source
*
 * @param usart2_sel periphral clock source @ref rcc_ccpipr_usartxsel
 */
void rcc_set_usart2_sel(uint32_t usart2_sel)
{
	RCC_CCIPR &= ~(RCC_CCIPR_USART2SEL_MASK << RCC_CCIPR_USART2SEL_SHIFT);
	RCC_CCIPR |= (usart2_sel << RCC_CCIPR_USART2SEL_SHIFT);
}

/*---------------------------------------------------------------------------*/
/** @brief Set the peripheral clock source
 * @param periph peripheral of desire, eg XXX_BASE
 * @param sel peripheral clock source
 */
void rcc_set_peripheral_clk_sel(uint32_t periph, uint32_t sel)
{
	uint8_t shift;
	uint32_t mask;

	switch (periph) {
		case LPTIM1_BASE:
			shift = RCC_CCIPR_LPTIM1SEL_SHIFT;
			mask = RCC_CCIPR_LPTIM1SEL_MASK;
			break;

		case I2C3_BASE:
			shift = RCC_CCIPR_I2C3SEL_SHIFT;
			mask = RCC_CCIPR_I2C3SEL_MASK;
			break;

		case I2C1_BASE:
			shift = RCC_CCIPR_I2C1SEL_SHIFT;
			mask = RCC_CCIPR_I2C1SEL_MASK;
			break;

		case LPUART1_BASE:
			shift = RCC_CCIPR_LPUART1SEL_SHIFT;
			mask = RCC_CCIPR_LPUART1SEL_MASK;
			break;

		case USART2_BASE:
			shift = RCC_CCIPR_USART2SEL_SHIFT;
			mask = RCC_CCIPR_USART2SEL_MASK;
			break;

		case USART1_BASE:
			shift = RCC_CCIPR_USART1SEL_SHIFT;
			mask = RCC_CCIPR_USART1SEL_MASK;
			break;

		default:
			return;
	}

	uint32_t reg32 = RCC_CCIPR & ~(mask << shift);
	RCC_CCIPR = reg32 | (sel << shift);
}


/* Helper to calculate the frequency of a clksel based clock. */
static uint32_t rcc_uart_i2c_clksel_freq_hz(uint32_t apb_clk, uint8_t shift) {
	uint8_t clksel = (RCC_CCIPR >> shift) & RCC_CCIPR_I2C1SEL_MASK;
	uint8_t hpre = (RCC_CFGR >> RCC_CFGR_HPRE_SHIFT) & RCC_CFGR_HPRE_MASK;
	switch (clksel) {
		case RCC_CCIPR_USART1SEL_APB:
			return apb_clk;
		case RCC_CCIPR_USART1SEL_SYS:
			return rcc_ahb_frequency * rcc_get_div_from_hpre(hpre);
		case RCC_CCIPR_USART1SEL_HSI16:
			return 16000000U;
	}
	cm3_assert_not_reached();
}

/*---------------------------------------------------------------------------*/
/** @brief Get the peripheral clock speed for the USART at base specified.
 * @param usart  Base address of USART to get clock frequency for.
 */
uint32_t rcc_get_usart_clk_freq(uint32_t usart)
{
	if (usart == LPUART1_BASE) {
		return rcc_uart_i2c_clksel_freq_hz(rcc_apb1_frequency, RCC_CCIPR_LPUART1SEL_SHIFT);
	} else if (usart == USART1_BASE) {
			return rcc_uart_i2c_clksel_freq_hz(rcc_apb2_frequency, RCC_CCIPR_USART1SEL_SHIFT);
	} else {
			return rcc_uart_i2c_clksel_freq_hz(rcc_apb1_frequency, RCC_CCIPR_USART2SEL_SHIFT);
	}
}

/*---------------------------------------------------------------------------*/
/** @brief Get the peripheral clock speed for the Timer at base specified.
 * @param timer  Base address of TIM to get clock frequency for.
 */
uint32_t rcc_get_timer_clk_freq(uint32_t timer)
{
	/* Handle APB1 timers, and apply multiplier if necessary. */
	if (timer >= TIM2_BASE && timer <= TIM7_BASE) {
		uint8_t ppre1 = (RCC_CFGR >> RCC_CFGR_PPRE1_SHIFT) & RCC_CFGR_PPRE1_MASK;
		return (ppre1 == RCC_CFGR_PPRE1_NODIV) ? rcc_apb1_frequency
			: 2 * rcc_apb1_frequency;
	} else {
		uint8_t ppre2 = (RCC_CFGR >> RCC_CFGR_PPRE2_SHIFT) & RCC_CFGR_PPRE2_MASK;
		return (ppre2 == RCC_CFGR_PPRE2_NODIV) ? rcc_apb2_frequency
			: 2 * rcc_apb2_frequency;
	}

}

/*---------------------------------------------------------------------------*/
/** @brief Get the peripheral clock speed for the I2C device at base specified.
 * @param i2c  Base address of I2C to get clock frequency for.
 */
uint32_t rcc_get_i2c_clk_freq(uint32_t i2c)
{
	if (i2c ==  I2C1_BASE) {
		return rcc_uart_i2c_clksel_freq_hz(rcc_apb1_frequency, RCC_CCIPR_I2C1SEL_SHIFT);
	} else if (i2c == I2C3_BASE) {
			return rcc_uart_i2c_clksel_freq_hz(rcc_apb1_frequency, RCC_CCIPR_I2C3SEL_SHIFT);
	} else {
		return rcc_apb1_frequency;
	}
}

/*---------------------------------------------------------------------------*/
/** @brief Get the peripheral clock speed for the SPI device at base specified.
 * @param spi  Base address of SPI device to get clock frequency for (e.g. SPI1_BASE).
 */
uint32_t rcc_get_spi_clk_freq(uint32_t spi) {
	if (spi == SPI1_BASE) {
		return rcc_apb2_frequency;
	} else {
		return rcc_apb1_frequency;
	}
}

/** @brief RCC Setup PLL and use it as Sysclk source.
 *
 * @param[in] clock full struct with desired parameters
 *
 */
void rcc_clock_setup_pll(const struct rcc_clock_scale *clock)
{
	/* Turn on the appropriate source for the PLL */
	if (clock->pll_source == RCC_CFGR_PLLSRC_HSE_CLK) {
		rcc_osc_on(RCC_HSE);
		rcc_wait_for_osc_ready(RCC_HSE);
	} else {
		rcc_osc_on(RCC_HSI16);
		rcc_wait_for_osc_ready(RCC_HSI16);
	}

	rcc_set_hpre(clock->hpre);
	rcc_set_ppre1(clock->ppre1);
	rcc_set_ppre2(clock->ppre2);

	rcc_periph_clock_enable(RCC_PWR);
	pwr_set_vos_scale(clock->voltage_scale);

	rcc_osc_off(RCC_PLL);
	while (rcc_is_osc_ready(RCC_PLL));

	flash_prefetch_enable();
	flash_set_ws(clock->flash_waitstates);

	/* Set up the PLL */
	rcc_set_pll_multiplier(clock->pll_mul);
	rcc_set_pll_divider(clock->pll_div);
	rcc_set_pll_source(clock->pll_source);

	rcc_osc_on(RCC_PLL);
	rcc_wait_for_osc_ready(RCC_PLL);
	rcc_set_sysclk_source(RCC_PLL);

	/* Set the peripheral clock frequencies used. */
	rcc_ahb_frequency = clock->ahb_frequency;
	rcc_apb1_frequency = clock->apb1_frequency;
	rcc_apb2_frequency = clock->apb2_frequency;
}

/**@}*/