diff options
| -rw-r--r-- | drivers/rtc/rtc-stm32.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c index bd7a59a07537..cad88668bcfb 100644 --- a/drivers/rtc/rtc-stm32.c +++ b/drivers/rtc/rtc-stm32.c @@ -114,6 +114,7 @@ struct stm32_rtc_data { void (*clear_events)(struct stm32_rtc *rtc, unsigned int flags); bool has_pclk; bool need_dbp; + bool need_accuracy; }; struct stm32_rtc { @@ -545,6 +546,7 @@ static void stm32_rtc_clear_events(struct stm32_rtc *rtc, static const struct stm32_rtc_data stm32_rtc_data = { .has_pclk = false, .need_dbp = true, + .need_accuracy = false, .regs = { .tr = 0x00, .dr = 0x04, @@ -566,6 +568,7 @@ static const struct stm32_rtc_data stm32_rtc_data = { static const struct stm32_rtc_data stm32h7_rtc_data = { .has_pclk = true, .need_dbp = true, + .need_accuracy = false, .regs = { .tr = 0x00, .dr = 0x04, @@ -596,6 +599,7 @@ static void stm32mp1_rtc_clear_events(struct stm32_rtc *rtc, static const struct stm32_rtc_data stm32mp1_data = { .has_pclk = true, .need_dbp = false, + .need_accuracy = true, .regs = { .tr = 0x00, .dr = 0x04, @@ -636,11 +640,25 @@ static int stm32_rtc_init(struct platform_device *pdev, pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT; pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT; - for (pred_a = pred_a_max; pred_a + 1 > 0; pred_a--) { - pred_s = (rate / (pred_a + 1)) - 1; + if (rate > (pred_a_max + 1) * (pred_s_max + 1)) { + dev_err(&pdev->dev, "rtc_ck rate is too high: %dHz\n", rate); + return -EINVAL; + } + + if (rtc->data->need_accuracy) { + for (pred_a = 0; pred_a <= pred_a_max; pred_a++) { + pred_s = (rate / (pred_a + 1)) - 1; - if (((pred_s + 1) * (pred_a + 1)) == rate) - break; + if (pred_s <= pred_s_max && ((pred_s + 1) * (pred_a + 1)) == rate) + break; + } + } else { + for (pred_a = pred_a_max; pred_a + 1 > 0; pred_a--) { + pred_s = (rate / (pred_a + 1)) - 1; + + if (((pred_s + 1) * (pred_a + 1)) == rate) + break; + } } /* |