From d3ff5476e004d08a4db227a5b13d9cc6cc77095c Mon Sep 17 00:00:00 2001
From: Jukka Laitinen <jukka.laitinen@iki.fi>
Date: Tue, 30 Apr 2019 07:15:37 -0600
Subject: [PATCH] arch/arm/src/stm32h7/stm32h7x3xx_rcc.c:  Set the stm32h7
 default HSI predivider to 4.  The I2C driver currently assumes HSI clock to
 be 16MHz.

---
 arch/arm/src/stm32h7/stm32h7x3xx_rcc.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm/src/stm32h7/stm32h7x3xx_rcc.c b/arch/arm/src/stm32h7/stm32h7x3xx_rcc.c
index 72ae5baa2ce..4c71fd31684 100644
--- a/arch/arm/src/stm32h7/stm32h7x3xx_rcc.c
+++ b/arch/arm/src/stm32h7/stm32h7x3xx_rcc.c
@@ -104,7 +104,13 @@ static inline void rcc_reset(void)
   regval  = getreg32(STM32_RCC_CR);
   regval &= ~(RCC_CR_HSEON | RCC_CR_HSI48ON |
               RCC_CR_CSION | RCC_CR_PLL1ON |
-              RCC_CR_PLL2ON | RCC_CR_PLL3ON);
+              RCC_CR_PLL2ON | RCC_CR_PLL3ON |
+              RCC_CR_HSIDIV_MASK);
+
+  /* Set HSI predivider to default (4, 16MHz) */
+
+  regval |= RCC_CR_HSIDIV_4;
+
   putreg32(regval, STM32_RCC_CR);
 
   /* Reset PLLCFGR register to reset default */