diff --git a/drivers/st/clk/stm32mp1_clk.c b/drivers/st/clk/stm32mp1_clk.c
index dbe2b83..fcc2f27 100644
--- a/drivers/st/clk/stm32mp1_clk.c
+++ b/drivers/st/clk/stm32mp1_clk.c
@@ -56,6 +56,7 @@
 	_HSI_KER = NB_OSC,
 	_HSE_KER,
 	_HSE_KER_DIV2,
+	_HSE_RTC,
 	_CSI_KER,
 	_PLL1_P,
 	_PLL1_Q,
@@ -125,6 +126,7 @@
 	[_HSI_KER] = CK_HSI,
 	[_HSE_KER] = CK_HSE,
 	[_HSE_KER_DIV2] = CK_HSE_DIV2,
+	[_HSE_RTC] = _UNKNOWN_ID,
 	[_CSI_KER] = CK_CSI,
 	[_PLL1_P] = PLL1_P,
 	[_PLL1_Q] = PLL1_Q,
@@ -490,7 +492,7 @@
 };
 
 static const uint8_t rtc_parents[] = {
-	_UNKNOWN_ID, _LSE, _LSI, _HSE
+	_UNKNOWN_ID, _LSE, _LSI, _HSE_RTC
 };
 
 static const struct stm32mp1_clk_sel stm32mp1_clk_sel[_PARENT_SEL_NB] = {
@@ -587,6 +589,7 @@
 	[_HSI_KER] = "HSI_KER",
 	[_HSE_KER] = "HSE_KER",
 	[_HSE_KER_DIV2] = "HSE_KER_DIV2",
+	[_HSE_RTC] = "HSE_RTC",
 	[_CSI_KER] = "CSI_KER",
 	[_PLL1_P] = "PLL1_P",
 	[_PLL1_Q] = "PLL1_Q",
@@ -969,6 +972,10 @@
 	case _HSE_KER_DIV2:
 		clock = stm32mp1_clk_get_fixed(_HSE) >> 1;
 		break;
+	case _HSE_RTC:
+		clock = stm32mp1_clk_get_fixed(_HSE);
+		clock /= (mmio_read_32(rcc_base + RCC_RTCDIVR) & RCC_DIVR_DIV_MASK) + 1U;
+		break;
 	case _LSI:
 		clock = stm32mp1_clk_get_fixed(_LSI);
 		break;
@@ -2152,6 +2159,7 @@
 	case _HSE:
 	case _HSE_KER:
 	case _HSE_KER_DIV2:
+	case _HSE_RTC:
 	case _LSE:
 		break;