From 26cb7f0ded33653dfd862bc97c1c6280a997b6b2 Mon Sep 17 00:00:00 2001
From: dragonmux <git@dragonmux.network>
Date: Mon, 13 May 2024 23:23:24 +0100
Subject: [PATCH] stm32/h7: Implemented support for the LSI clock source

---
 include/libopencm3/stm32/h7/rcc.h | 5 +++++
 lib/stm32/h7/rcc.c                | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/include/libopencm3/stm32/h7/rcc.h b/include/libopencm3/stm32/h7/rcc.h
index 8176956b..50909dba 100644
--- a/include/libopencm3/stm32/h7/rcc.h
+++ b/include/libopencm3/stm32/h7/rcc.h
@@ -778,6 +778,11 @@ void rcc_clock_setup_pll(const struct rcc_pll_config *config);
  */
 void rcc_clock_setup_hsi48(void);
 
+/**
+ * Setup and bring up the LSI.
+ */
+void rcc_clock_setup_lsi(void);
+
 /**
  * Get the clock rate (in Hz) of the specified clock source. There are
  * numerous clock sources and configurations on the H7, so rates for each
diff --git a/lib/stm32/h7/rcc.c b/lib/stm32/h7/rcc.c
index 9393edc5..c46b42fb 100644
--- a/lib/stm32/h7/rcc.c
+++ b/lib/stm32/h7/rcc.c
@@ -230,6 +230,13 @@ void rcc_clock_setup_hsi48(void)
 		continue;
 }
 
+void rcc_clock_setup_lsi(void)
+{
+	RCC_CSR |= RCC_CSR_LSION;
+	while (!(RCC_CSR & RCC_CSR_LSIRDY))
+		continue;
+}
+
 uint32_t rcc_get_bus_clk_freq(enum rcc_clock_source source) {
 	uint32_t clksel;
 	switch (source) {