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stm32: added peripheral clock get helpers for all stm32 platforms.

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Allows for abstraction for code that's dependent on knowing the source clock
for a peripheral. Implemented a few core peripherals that tend to have clock
tree differences between platforms (USART, timers, I2C, SPI).
This commit is contained in:
Brian Viele
2020-03-06 00:57:21 -05:00
committed by Karl Palsson
parent df55d45cc1
commit e41ac6ea71
24 changed files with 860 additions and 94 deletions
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87
lib/stm32/f7/rcc.c
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@@ -484,4 +484,91 @@ void rcc_clock_setup_hsi(const struct rcc_clock_scale *clock)
rcc_apb2_frequency = clock->apb2_frequency;
}
static uint32_t rcc_usart_i2c_clksel_freq(uint32_t apb_clk, uint8_t shift) {
uint8_t clksel = (RCC_DCKCFGR2 >> shift) & RCC_DCKCFGR2_UART1SEL_MASK;
uint8_t hpre = (RCC_CFGR >> RCC_CFGR_HPRE_SHIFT) & RCC_CFGR_HPRE_MASK;
switch (clksel) {
case RCC_DCKCFGR2_UARTxSEL_PCLK:
return apb_clk;
case RCC_DCKCFGR2_UARTxSEL_SYSCLK:
return rcc_ahb_frequency * rcc_get_div_from_hpre(hpre);
case RCC_DCKCFGR2_UARTxSEL_HSI:
return 16000000U;
default:
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)
{
/* F7 is highly configurable, every USART can be configured in DCKCFGR2. */
if (usart == USART1_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb2_frequency, RCC_DCKCFGR2_UART1SEL_SHIFT);
} else if (usart == USART2_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_UART2SEL_SHIFT);
} else if (usart == USART3_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_UART3SEL_SHIFT);
} else if (usart == UART4_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_UART4SEL_SHIFT);
} else if (usart == UART5_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_UART5SEL_SHIFT);
} else if (usart == USART6_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb2_frequency, RCC_DCKCFGR2_USART6SEL_SHIFT);
} else if (usart == UART7_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_UART7SEL_SHIFT);
} else { /* UART8 */
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_UART8SEL_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 timer clocks. */
if (timer >= TIM2_BASE && timer <= TIM14_BASE) {
uint8_t ppre1 = (RCC_CFGR >> RCC_CFGR_PPRE1_SHIFT) & RCC_CFGR_PPRE1_MASK;
return (ppre1 == RCC_CFGR_PPRE_DIV_NONE) ? 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_PPRE_DIV_NONE) ? 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 __attribute__((unused)))
{
if (i2c == I2C1_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_I2C1SEL_SHIFT);
} else if (i2c == I2C2_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_I2C2SEL_SHIFT);
} else if (i2c == I2C3_BASE) {
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_I2C3SEL_SHIFT);
} else { /* I2C4 */
return rcc_usart_i2c_clksel_freq(rcc_apb1_frequency, RCC_DCKCFGR2_I2C4SEL_SHIFT);
}
}
/*---------------------------------------------------------------------------*/
/** @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 == SPI2_BASE || spi == SPI3_BASE) {
return rcc_apb1_frequency;
} else {
return rcc_apb2_frequency;
}
}
/**@}*/