From f69cb2d6034ddf8dae6848d29b9d4efba8cd4df9 Mon Sep 17 00:00:00 2001 From: Antonio Borneo Date: Wed, 5 Jul 2023 19:43:51 +0200 Subject: [PATCH] rtc: stm32: use the proper register sequence to read date/time Date and time are read from two separate RTC registers. To ensure consistency between the two registers, reading the time register locks the values in the shadow date register until the date register is read. Thus, the whole date/time read requires reading the time register first, followed by reading the date register. If the reads are done in reversed order, the shadow date register will remain locked until a future read operation. The future read will read the former date value that could be already invalid. Fix the read order of date/time registers in stm32_rtc_valid_alrm() Signed-off-by: Antonio Borneo Signed-off-by: Valentin Caron Link: https://lore.kernel.org/r/20230705174357.353616-2-valentin.caron@foss.st.com Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-stm32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c index 3d36e11cff80..abb77ad774a1 100644 --- a/drivers/rtc/rtc-stm32.c +++ b/drivers/rtc/rtc-stm32.c @@ -429,8 +429,8 @@ static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm) { const struct stm32_rtc_registers *regs = &rtc->data->regs; int cur_day, cur_mon, cur_year, cur_hour, cur_min, cur_sec; - unsigned int dr = readl_relaxed(rtc->base + regs->dr); unsigned int tr = readl_relaxed(rtc->base + regs->tr); + unsigned int dr = readl_relaxed(rtc->base + regs->dr); cur_day = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT; cur_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT; -- 2.39.5