RCC: Clean up and sanitize interfaces across F1, F2 series.

Additions:

- rcc_switch_sysclk():

  For changing the clock used as SYSCLK's source.

- enum rcc_clk:

  One for each system and secondary clock source (e.g. HSE,
  LSE). These are defined on a per-series basis in each of the
  <series/rcc.h>.

- rcc_turn_on_clk(),
  rcc_turn_off_clk(),
  rcc_is_clk_ready():

  For turning on system and secondary clock sources, and checking
  whether or not they're ready. Uses enum rcc_clk.

Removals:

- rcc_clk_init(): There's no way to port this to F2. Move it to the F1
  header. This also means we can remove the empty implementation and
  enum rcc_pll_multiplier from the F2 RCC header, where it doesn't
  make any sense.

Also fix up some includes, and rewrite rcc_clk_init() in terms of the
new clock source management functions.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

2 files changed, 30 insertions, 11 deletions

diff --git a/libmaple/stm32f2/include/series/rcc.h b/libmaple/stm32f2/include/series/rcc.h
index 1557f2d..89fed1d 100644
--- a/libmaple/stm32f2/include/series/rcc.h
+++ b/libmaple/stm32f2/include/series/rcc.h
@@ -722,7 +722,6 @@ typedef struct rcc_reg_map {
 
 /* Spread spectrum clock generation register */
 
-
 #define RCC_SSCGR_SSCGEN_BIT            31
 #define RCC_SSCGR_SPREADSEL_BIT         30
 
@@ -742,6 +741,10 @@ typedef struct rcc_reg_map {
  * Other types
  */
 
+/*
+ * Clock sources, domains, and peripheral clock IDs.
+ */
+
 /**
  * @brief Identifies bus and clock line for a peripheral or peripheral
  *        clock.
@@ -819,10 +822,6 @@ typedef enum rcc_pllsrc {
     RCC_PLLSRC_HSE = RCC_PLLCFGR_PLLSRC,
 } rcc_pllsrc;
 
-typedef enum rcc_pll_multiplier { /* TODO -- does this make sense anymore? */
-    RCC_PLLMUL_XXX,
-} rcc_pll_multiplier;
-
 /**
  * @brief Peripheral clock domains.
  */
@@ -834,6 +833,10 @@ typedef enum rcc_clk_domain {
     RCC_AHB3,
 } rcc_clk_domain;
 
+/*
+ * Prescalers and dividers.
+ */
+
 /**
  * @brief Prescaler identifiers.
  */
@@ -912,6 +915,28 @@ typedef enum rcc_ahb_divider {
     RCC_AHB_SYSCLK_DIV_512 = RCC_CFGR_HPRE_SYSCLK_DIV_512,
 } rcc_ahb_divider;
 
+/**
+ * @brief Available clock sources.
+ */
+typedef enum rcc_clk {
+    RCC_CLK_PLLI2S = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |
+                              RCC_CR_PLLI2SON_BIT), /**< Dedicated PLL
+                                                       for I2S. */
+    RCC_CLK_PLL    = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |
+                              RCC_CR_PLLON_BIT), /**< Main PLL, clocked by
+                                                    HSI or HSE. */
+    RCC_CLK_HSE    = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |
+                              RCC_CR_HSEON_BIT), /**< High speed external. */
+    RCC_CLK_HSI    = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |
+                              RCC_CR_HSION_BIT), /**< High speed internal. */
+    RCC_CLK_LSE    = (uint16)((offsetof(struct rcc_reg_map, BDCR) << 8) |
+                              RCC_BDCR_LSEON_BIT), /**< Low-speed external
+                                                    * (32.768 KHz). */
+    RCC_CLK_LSI    = (uint16)((offsetof(struct rcc_reg_map, CSR) << 8) |
+                              RCC_CSR_LSION_BIT), /**< Low-speed internal
+                                                   * (approximately 32 KHz). */
+} rcc_clk;
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/libmaple/stm32f2/rcc.c b/libmaple/stm32f2/rcc.c
index 268a9b1..7bc220d 100644
--- a/libmaple/stm32f2/rcc.c
+++ b/libmaple/stm32f2/rcc.c
@@ -110,12 +110,6 @@ const struct rcc_dev_info rcc_dev_table[] = {
     [RCC_TIM1]   = DEV_ENTRY(APB2, TIM1),
 };
 
-void rcc_clk_init(rcc_sysclk_src sysclk_src,
-                  rcc_pllsrc pll_src,
-                  rcc_pll_multiplier pll_mul) {
-    ASSERT(0);                    /* FIXME */
-}
-
 /**
  * @brief Turn on the clock line on a peripheral
  * @param id Clock ID of the peripheral to turn on.