fix(st-clock): do not reconfigure LSE

If LSE oscillator is already ON, which is the case when returning from
low-power state or if we are on VBAT, it mustn't be reconfigured.

Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Change-Id: Ie75f2b0b42aeb3d95e2266e1fca811a2f2b3e29f
diff --git a/drivers/st/clk/clk-stm32mp13.c b/drivers/st/clk/clk-stm32mp13.c
index 01d1764..baa0770 100644
--- a/drivers/st/clk/clk-stm32mp13.c
+++ b/drivers/st/clk/clk-stm32mp13.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022-2023, STMicroelectronics - All Rights Reserved
+ * Copyright (C) 2022-2024, STMicroelectronics - All Rights Reserved
  *
  * SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
  */
@@ -1007,6 +1007,11 @@
 		return;
 	}
 
+	/* Do not reconfigure LSE if already enabled */
+	if (_clk_stm32_gate_is_enabled(priv, osc_data->gate_id)) {
+		return;
+	}
+
 	clk_oscillator_set_bypass(priv, _CK_LSE, digbyp, bypass);
 
 	clk_oscillator_set_drive(priv, _CK_LSE, drive);
diff --git a/drivers/st/clk/stm32mp1_clk.c b/drivers/st/clk/stm32mp1_clk.c
index 818fd85..4dd1017 100644
--- a/drivers/st/clk/stm32mp1_clk.c
+++ b/drivers/st/clk/stm32mp1_clk.c
@@ -1327,6 +1327,11 @@
 	uint32_t value;
 	uintptr_t rcc_base = stm32mp_rcc_base();
 
+	/* Do not reconfigure LSE if it is already ON */
+	if ((mmio_read_32(rcc_base + RCC_BDCR) & RCC_BDCR_LSEON) == RCC_BDCR_LSEON) {
+		return;
+	}
+
 	if (digbyp) {
 		mmio_setbits_32(rcc_base + RCC_BDCR, RCC_BDCR_DIGBYP);
 	}