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drivers: rtc: stm32: avoid using LL_RTC_Init

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LL_RTC_Init() internally uses LL_RTC_EnterInitMode() wich uses a blocking
while loop. This rewrite uses the less CPU time wasteful local
rtc_stm32_enter_initialization_mode() instead. As a side effect
LL_RTC_InitTypeDef in rtc_stm32_config is not needed anymore.

Signed-off-by: Johan Lafon <johan.lafon@syslinbit.com>
This commit is contained in:
Johan Lafon 2023-09-11 17:47:57 +02:00 • committed by Fabio Baltieri
commit e46aff5902
2 changed files with 31 additions and 29 deletions
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1
drivers/rtc/Kconfig.stm32
View file

@ -5,7 +5,6 @@ config RTC_STM32
bool "STM32 RTC driver"
default y if !COUNTER
depends on DT_HAS_ST_STM32_RTC_ENABLED && !SOC_SERIES_STM32F1X
select USE_STM32_LL_RTC
select USE_STM32_LL_PWR
select USE_STM32_LL_RCC
help

59
drivers/rtc/rtc_ll_stm32.c
View file

@ -61,7 +61,8 @@ LOG_MODULE_REGISTER(rtc_stm32, CONFIG_RTC_LOG_LEVEL);
#define RTC_TIMEOUT 1000000
struct rtc_stm32_config {
LL_RTC_InitTypeDef ll_rtc_config;
uint32_t async_prescaler;
uint32_t sync_prescaler;
const struct stm32_pclken *pclken;
};
@ -91,22 +92,37 @@ static int rtc_stm32_configure(const struct device *dev)
{
const struct rtc_stm32_config *cfg = dev->config;
int err = 0;
uint32_t hour_format = LL_RTC_GetHourFormat(RTC);
uint32_t sync_prescaler = LL_RTC_GetSynchPrescaler(RTC);
uint32_t async_prescaler = LL_RTC_GetAsynchPrescaler(RTC);
LL_RTC_DisableWriteProtection(RTC);
/* configuration process requires to stop the RTC counter so do it
* only if needed to avoid inducing time drift at each reset
*/
if ((hour_format != cfg->ll_rtc_config.HourFormat) ||
(sync_prescaler != cfg->ll_rtc_config.SynchPrescaler) ||
(async_prescaler != cfg->ll_rtc_config.AsynchPrescaler)) {
if (LL_RTC_Init(RTC, ((LL_RTC_InitTypeDef *)&cfg->ll_rtc_config)) != SUCCESS) {
return -EIO;
if ((hour_format != LL_RTC_HOURFORMAT_24HOUR) ||
(sync_prescaler != cfg->sync_prescaler) ||
(async_prescaler != cfg->async_prescaler)) {
err = rtc_stm32_enter_initialization_mode();
if (err == 0) {
LL_RTC_SetHourFormat(RTC, LL_RTC_HOURFORMAT_24HOUR);
LL_RTC_SetSynchPrescaler(RTC, cfg->sync_prescaler);
LL_RTC_SetAsynchPrescaler(RTC, cfg->async_prescaler);
}
rtc_stm32_leave_initialization_mode();
}
return 0;
#ifdef RTC_CR_BYPSHAD
LL_RTC_EnableShadowRegBypass(RTC);
#endif /* RTC_CR_BYPSHAD */
LL_RTC_EnableWriteProtection(RTC);
return err;
}
static int rtc_stm32_init(const struct device *dev)
@ -144,15 +160,6 @@ static int rtc_stm32_init(const struct device *dev)
z_stm32_hsem_unlock(CFG_HW_RCC_SEMID);
err = rtc_stm32_configure(dev);
if (err) {
return err;
}
#ifdef RTC_CR_BYPSHAD
LL_RTC_DisableWriteProtection(RTC);
LL_RTC_EnableShadowRegBypass(RTC);
LL_RTC_EnableWriteProtection(RTC);
#endif /* RTC_CR_BYPSHAD */
return err;
}
@ -160,18 +167,15 @@ static int rtc_stm32_init(const struct device *dev)
static const struct stm32_pclken rtc_clk[] = STM32_DT_INST_CLOCKS(0);
static const struct rtc_stm32_config rtc_config = {
.ll_rtc_config = {
.HourFormat = LL_RTC_HOURFORMAT_24HOUR,
#if DT_INST_CLOCKS_CELL(1, bus) == STM32_SRC_LSI
/* prescaler values for LSI @ 32 KHz */
.AsynchPrescaler = 0x7F,
.SynchPrescaler = 0x00F9,
/* prescaler values for LSI @ 32 KHz */
.async_prescaler = 0x7F,
.sync_prescaler = 0x00F9,
#else /* DT_INST_CLOCKS_CELL(1, bus) == STM32_SRC_LSE */
/* prescaler values for LSE @ 32768 Hz */
.AsynchPrescaler = 0x7F,
.SynchPrescaler = 0x00FF,
/* prescaler values for LSE @ 32768 Hz */
.async_prescaler = 0x7F,
.sync_prescaler = 0x00FF,
#endif
},
.pclken = rtc_clk,
};
@ -226,7 +230,6 @@ static int rtc_stm32_set_time(const struct device *dev, const struct rtc_time *t
static int rtc_stm32_get_time(const struct device *dev, struct rtc_time *timeptr)
{
const struct rtc_stm32_config *cfg = dev->config;
uint32_t sync_prescaler = cfg->ll_rtc_config.SynchPrescaler;
uint32_t rtc_date, rtc_time, rtc_subsecond;
@ -263,9 +266,9 @@ static int rtc_stm32_get_time(const struct device *dev, struct rtc_time *timeptr
timeptr->tm_min = __LL_RTC_CONVERT_BCD2BIN(__LL_RTC_GET_MINUTE(rtc_time));
timeptr->tm_sec = __LL_RTC_CONVERT_BCD2BIN(__LL_RTC_GET_SECOND(rtc_time));
uint64_t temp = ((uint64_t)(sync_prescaler - rtc_subsecond)) * 1000000000L;
uint64_t temp = ((uint64_t)(cfg->sync_prescaler - rtc_subsecond)) * 1000000000L;
timeptr->tm_nsec = DIV_ROUND_CLOSEST(temp, sync_prescaler + 1);
timeptr->tm_nsec = DIV_ROUND_CLOSEST(temp, cfg->sync_prescaler + 1);
return 0;
}