From 29ede503f3d34043a8c88ca248b5e8ae9803c8d2 Mon Sep 17 00:00:00 2001
From: Karl Palsson <karlp@tweak.net.au>
Date: Sun, 4 Oct 2015 00:27:14 +0000
Subject: [PATCH] stm32l0: rcc: add more helper routines.

---
 include/libopencm3/stm32/l0/rcc.h |   9 ++-
 lib/stm32/l0/rcc.c                | 112 ++++++++++++++++++++++++++++++
 2 files changed, 120 insertions(+), 1 deletion(-)

diff --git a/include/libopencm3/stm32/l0/rcc.h b/include/libopencm3/stm32/l0/rcc.h
index 2ffbadf9..0174b379 100644
--- a/include/libopencm3/stm32/l0/rcc.h
+++ b/include/libopencm3/stm32/l0/rcc.h
@@ -622,7 +622,14 @@ void rcc_osc_ready_int_enable(enum rcc_osc osc);
 void rcc_osc_ready_int_disable(enum rcc_osc osc);
 int rcc_osc_ready_int_flag(enum rcc_osc osc);
 void rcc_wait_for_osc_ready(enum rcc_osc osc);
-
+void rcc_set_hsi48_source_rc48(void);
+void rcc_set_hsi48_source_pll(void);
+void rcc_set_sysclk_source(enum rcc_osc osc);
+void rcc_set_pll_multiplier(uint32_t factor);
+void rcc_set_pll_divider(uint32_t factor);
+void rcc_set_ppre2(uint32_t ppre2);
+void rcc_set_ppre1(uint32_t ppre1);
+void rcc_set_hpre(uint32_t hpre);
 /* TODO */
 
 END_DECLS
diff --git a/lib/stm32/l0/rcc.c b/lib/stm32/l0/rcc.c
index 71c5b90e..af42c5ba 100644
--- a/lib/stm32/l0/rcc.c
+++ b/lib/stm32/l0/rcc.c
@@ -290,5 +290,117 @@ void rcc_wait_for_osc_ready(enum rcc_osc osc)
 	}
 }
 
+/*---------------------------------------------------------------------------*/
+/** @brief RCC Set HSI48 clock source to the RC48 (CRS)
+ */
+void rcc_set_hsi48_source_rc48(void) {
+	RCC_CCIPR |= RCC_CCIPR_HSI48SEL;
+}
+
+/*---------------------------------------------------------------------------*/
+/** @brief RCC Set HSI48 clock source to the PLL
+ */
+void rcc_set_hsi48_source_pll(void) {
+	RCC_CCIPR &= ~RCC_CCIPR_HSI48SEL;
+}
+
+/*---------------------------------------------------------------------------*/
+/** @brief RCC Set the Source for the System Clock.
+ *
+ * @param[in] osc enum ::osc_t. Oscillator ID. Only HSE, HSI16, MSI and PLL have
+ * effect.
+ */
+
+void rcc_set_sysclk_source(enum rcc_osc osc)
+{
+	switch (osc) {
+	case PLL:
+		RCC_CFGR |=  RCC_CFGR_SW_PLL;
+		break;
+	case HSE:
+		RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW_MASK) | RCC_CFGR_SW_HSE;
+		break;
+	case HSI16:
+		RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW_MASK) | RCC_CFGR_SW_HSI16;
+		break;
+	case MSI:
+		RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW_MASK) | RCC_CFGR_SW_MSI;
+		break;
+	case HSI48:
+	case LSE:
+	case LSI:
+		break;
+	}
+}
+
+/*---------------------------------------------------------------------------*/
+/** @brief RCC Set the PLL Multiplication Factor.
+ *
+ * @note This only has effect when the PLL is disabled.
+ *
+ * @param[in] mul Unsigned int32. PLL multiplication factor @ref rcc_cfgr_pmf
+ */
+
+void rcc_set_pll_multiplier(uint32_t factor)
+{
+	uint32_t reg = RCC_CFGR & ~(RCC_CFGR_PLLMUL_MASK<<RCC_CFGR_PLLMUL_SHIFT);
+	RCC_CFGR = reg | (factor << RCC_CFGR_PLLMUL_SHIFT);
+}
+
+
+/*---------------------------------------------------------------------------*/
+/** @brief RCC Set the PLL Division Factor.
+ *
+ * @note This only has effect when the PLL is disabled.
+ *
+ * @param[in] mul Unsigned int32. PLL multiplication factor @ref rcc_cfgr_pdf
+ */
+
+void rcc_set_pll_divider(uint32_t factor)
+{
+	uint32_t reg = RCC_CFGR & ~(RCC_CFGR_PLLDIV_MASK<<RCC_CFGR_PLLDIV_SHIFT);
+	RCC_CFGR = reg | (factor << RCC_CFGR_PLLDIV_SHIFT);
+}
+
+/*---------------------------------------------------------------------------*/
+/** @brief RCC Set the APB1 Prescale Factor.
+ *
+ * @note The APB1 clock frequency must not exceed 32MHz.
+ *
+ * @param[in] ppre1 Unsigned int32. APB prescale factor @ref rcc_cfgr_apb1pre
+ */
+
+void rcc_set_ppre1(uint32_t ppre)
+{
+	uint32_t reg = RCC_CFGR & ~(RCC_CFGR_PPRE1_MASK << RCC_CFGR_PPRE1_SHIFT);
+	RCC_CFGR = reg | (ppre << RCC_CFGR_PPRE1_SHIFT);
+}
+
+/*---------------------------------------------------------------------------*/
+/** @brief RCC Set the APB2 Prescale Factor.
+ *
+ * @note The APB2 clock frequency must not exceed 32MHz.
+ *
+ * @param[in] ppre1 Unsigned int32. APB prescale factor @ref rcc_cfgr_apb2pre
+ */
+
+void rcc_set_ppre2(uint32_t ppre)
+{
+	uint32_t reg = RCC_CFGR & ~(RCC_CFGR_PPRE2_MASK << RCC_CFGR_PPRE2_SHIFT);
+	RCC_CFGR = reg | (ppre << RCC_CFGR_PPRE2_SHIFT);
+}
+
+/*---------------------------------------------------------------------------*/
+/** @brief RCC Set the AHB Prescale Factor.
+ *
+ * @param[in] hpre Unsigned int32. AHB prescale factor @ref rcc_cfgr_ahbpre
+ */
+
+void rcc_set_hpre(uint32_t hpre)
+{
+	uint32_t reg = RCC_CFGR & ~(RCC_CFGR_HPRE_MASK << RCC_CFGR_HPRE_SHIFT);
+	RCC_CFGR = reg | (hpre << RCC_CFGR_HPRE_SHIFT);
+}
+
 
 /**@}*/