From c930fc392b6977b17d6f7953bd738583974208c2 Mon Sep 17 00:00:00 2001
From: Kevin O'Connor <kevin@koconnor.net>
Date: Tue, 20 Aug 2019 01:04:20 -0400
Subject: stm32: Make sure to enable the gpio clock prior to setting the first
 value

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
---
 src/stm32/stm32f4.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

(limited to 'src/stm32/stm32f4.c')

diff --git a/src/stm32/stm32f4.c b/src/stm32/stm32f4.c
index dab8d524..5a09f2d6 100644
--- a/src/stm32/stm32f4.c
+++ b/src/stm32/stm32f4.c
@@ -53,6 +53,15 @@ get_pclock_frequency(uint32_t periph_base)
     return FREQ_PERIPH;
 }
 
+// Enable a GPIO peripheral clock
+void
+gpio_clock_enable(GPIO_TypeDef *regs)
+{
+    uint32_t rcc_pos = ((uint32_t)regs - AHB1PERIPH_BASE) / 0x400;
+    RCC->AHB1ENR |= 1 << rcc_pos;
+    RCC->AHB1ENR;
+}
+
 // Set the mode and extended function of a pin
 void
 gpio_peripheral(uint32_t gpio, uint32_t mode, int pullup)
@@ -60,8 +69,7 @@ gpio_peripheral(uint32_t gpio, uint32_t mode, int pullup)
     GPIO_TypeDef *regs = digital_regs[GPIO2PORT(gpio)];
 
     // Enable GPIO clock
-    uint32_t rcc_pos = ((uint32_t)regs - AHB1PERIPH_BASE) / 0x400;
-    RCC->AHB1ENR |= (1<<rcc_pos);
+    gpio_clock_enable(regs);
 
     // Configure GPIO
     uint32_t mode_bits = mode & 0x0f, func = mode >> 4;
-- 
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