stm32f4: refactor GPIO, in prep for adding SPI, I2C, PWM etc

src/device/stm32/stm32-moder-bitfields.go

@@ -0,0 +1,45 @@
+// Hand created file. DO NOT DELETE.
+// STM32FXXX (except stm32f1xx) bitfield definitions that are not
+//  auto-generated by gen-device-svd.go
+
+// These apply to the stm32 families that use the MODER, OTYPE amd PUPDR
+//  registers for managing GPIO functionality.
+
+// Add in other families that use the same settings, e.g. stm32f0xx, etc
+
+// +build stm32,!stm32f103xx
+
+package stm32
+
+// AltFunc represents the alternate function peripherals that can be mapped to
+// the GPIO ports. Since these differ by what is supported on the stm32 family
+// they are defined in the more specific files
+type AltFunc uint8
+
+// Family-wide common post-reset AltFunc. This represents
+//  normal GPIO operation of the pins
+const AF0_SYSTEM AltFunc = 0
+
+const (
+	// Register values for the chip
+	// GPIOx_MODER
+	GPIOModeInput         = 0
+	GPIOModeOutputGeneral = 1
+	GPIOModeOutputAltFunc = 2
+	GPIOModeAnalog        = 3
+
+	// GPIOx_OTYPER
+	GPIOOutputTypePushPull  = 0
+	GPIOOutputTypeOpenDrain = 1
+
+	// GPIOx_OSPEEDR
+	GPIOSpeedLow      = 0
+	GPIOSpeedMid      = 1
+	GPIOSpeedHigh     = 2 // Note: this is also low speed on stm32f0, see RM0091
+	GPIOSpeedVeryHigh = 3
+
+	// GPIOx_PUPDR
+	GPIOPUPDRFloating = 0
+	GPIOPUPDRPullUp   = 1
+	GPIOPUPDRPullDown = 2
+)

src/device/stm32/stm32f407xx-altfunc-bitfields.go

@@ -0,0 +1,26 @@
+// These are the supported alternate function numberings on the stm32f407
+// +build stm32,stm32f407
+
+// Alternate function settings on the stm32f4xx series
+
+package stm32
+
+const (
+	// Alternative peripheral pin functions
+	// AF0_SYSTEM is defined im the common bitfields package
+	AF1_TIM1_2                AltFunc = 1
+	AF2_TIM3_4_5                      = 2
+	AF3_TIM8_9_10_11                  = 3
+	AF4_I2C1_2_3                      = 4
+	AF5_SPI1_SPI2                     = 5
+	AF6_SPI3                          = 6
+	AF7_USART1_2_3                    = 7
+	AF8_USART4_5_6                    = 8
+	AF9_CAN1_CAN2_TIM12_13_14         = 9
+	AF10_OTG_FS_OTG_HS                = 10
+	AF11_ETH                          = 11
+	AF12_FSMC_SDIO_OTG_HS_1           = 12
+	AF13_DCMI                         = 13
+	AF14                              = 14
+	AF15_EVENTOUT                     = 15
+)