From 0d5e51a8a7b24c8bc93ca849eb670bc55b02e091 Mon Sep 17 00:00:00 2001
From: Matt Anderson <mda2376@gmail.com>
Date: Sat, 17 Mar 2018 15:31:27 -0400
Subject: [PATCH] STM32F0: Add RCC API for I2C1 clock source

* Providing API to set/clear RCC_CFGR3_I2C1SW on STM32F0, duplicated
	from STM32F3 applies only to I2C1.
---
 include/libopencm3/stm32/f0/rcc.h |  3 +++
 lib/stm32/f0/rcc.c                | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/include/libopencm3/stm32/f0/rcc.h b/include/libopencm3/stm32/f0/rcc.h
index 5872c7a2..ab066ea7 100644
--- a/include/libopencm3/stm32/f0/rcc.h
+++ b/include/libopencm3/stm32/f0/rcc.h
@@ -533,6 +533,9 @@ void rcc_set_ppre(uint32_t ppre);
 void rcc_set_hpre(uint32_t hpre);
 void rcc_set_prediv(uint32_t prediv);
 enum rcc_osc rcc_system_clock_source(void);
+void rcc_set_i2c_clock_hsi(uint32_t i2c);
+void rcc_set_i2c_clock_sysclk(uint32_t i2c);
+uint32_t rcc_get_i2c_clocks(void);
 enum rcc_osc rcc_usb_clock_source(void);
 void rcc_clock_setup_in_hse_8mhz_out_48mhz(void);
 void rcc_clock_setup_in_hsi_out_48mhz(void);
diff --git a/lib/stm32/f0/rcc.c b/lib/stm32/f0/rcc.c
index fa85aeaf..d4b79e5d 100644
--- a/lib/stm32/f0/rcc.c
+++ b/lib/stm32/f0/rcc.c
@@ -39,6 +39,7 @@
 #include <libopencm3/cm3/assert.h>
 #include <libopencm3/stm32/rcc.h>
 #include <libopencm3/stm32/flash.h>
+#include <libopencm3/stm32/i2c.h>
 
 /* Set the default clock frequencies */
 uint32_t rcc_ahb_frequency = 8000000; /* 8MHz after reset */
@@ -520,6 +521,25 @@ enum rcc_osc rcc_system_clock_source(void)
 	cm3_assert_not_reached();
 }
 
+void rcc_set_i2c_clock_hsi(uint32_t i2c)
+{
+	if (i2c == I2C1) {
+		RCC_CFGR3 &= ~RCC_CFGR3_I2C1SW;
+	}
+}
+
+void rcc_set_i2c_clock_sysclk(uint32_t i2c)
+{
+	if (i2c == I2C1) {
+		RCC_CFGR3 |= RCC_CFGR3_I2C1SW;
+	}
+}
+
+uint32_t rcc_get_i2c_clocks(void)
+{
+	return RCC_CFGR3 & RCC_CFGR3_I2C1SW;
+}
+
 /*---------------------------------------------------------------------------*/
 /** @brief RCC Get the USB Clock Source.
  *