pinmux: stm32f4: Clean-up pinmux arrays

Clean-up the pinmux arrays as a preparatory work before adding more
pinmuxes.

This is achieved by the following two actions:
- Define the PAD macro to simplify the [x - 1] = y construct
- Reorder the declartions by bank / pin to make it easier to
  locate a pin among a high number of other pins, while minimizing the
  risk of conflict when two people add a new declaration for two
  different pins

Change-Id: I1ca0cc4f48bcd8cfd35b331e9821935f5c855876
Signed-off-by: Florian Vaussard <florian.vaussard@heig-vd.ch>

Author: Florian Vaussard

arch/arm/soc/st_stm32/stm32f4/soc_pinmux.c

@@ -12,52 +12,48 @@
 #include <pinmux/stm32/pinmux_stm32.h>
 #include <drivers/clock_control/stm32_clock_control.h>
 
-static const stm32_pin_func_t pin_pa9_funcs[] = {
-	[STM32F4_PINMUX_FUNC_PA9_USART1_TX - 1] =
-			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+#define PAD(AF, func)				\
+				[AF - 1] = func
+
+static const stm32_pin_func_t pin_pa0_funcs[] = {
+	PAD(STM32F4_PINMUX_FUNC_PA0_PWM2_CH1, STM32F4X_PIN_CONFIG_AF_PUSH_UP),
 };
 
-static const stm32_pin_func_t pin_pa10_funcs[] = {
-	[STM32F4_PINMUX_FUNC_PA10_USART1_RX - 1] =
-			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+static const stm32_pin_func_t pin_pa2_funcs[] = {
+	PAD(STM32F4_PINMUX_FUNC_PA2_USART2_TX, STM32F4X_PIN_CONFIG_AF_PUSH_UP),
 };
 
-static const stm32_pin_func_t pin_pb6_funcs[] = {
-	[STM32F4_PINMUX_FUNC_PB6_USART1_TX - 1] =
-			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+static const stm32_pin_func_t pin_pa3_funcs[] = {
+	PAD(STM32F4_PINMUX_FUNC_PA3_USART2_RX, STM32F4X_PIN_CONFIG_AF_PUSH_UP),
 };
 
-static const stm32_pin_func_t pin_pb7_funcs[] = {
-	[STM32F4_PINMUX_FUNC_PB7_USART1_RX - 1] =
-			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+static const stm32_pin_func_t pin_pa9_funcs[] = {
+	PAD(STM32F4_PINMUX_FUNC_PA9_USART1_TX, STM32F4X_PIN_CONFIG_AF_PUSH_UP),
 };
 
-static const stm32_pin_func_t pin_pa2_funcs[] = {
-	[STM32F4_PINMUX_FUNC_PA2_USART2_TX - 1] =
-			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+static const stm32_pin_func_t pin_pa10_funcs[] = {
+	PAD(STM32F4_PINMUX_FUNC_PA10_USART1_RX, STM32F4X_PIN_CONFIG_AF_PUSH_UP)
 };
 
-static const stm32_pin_func_t pin_pa3_funcs[] = {
-	[STM32F4_PINMUX_FUNC_PA3_USART2_RX - 1] =
-			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+static const stm32_pin_func_t pin_pb6_funcs[] = {
+	PAD(STM32F4_PINMUX_FUNC_PB6_USART1_TX, STM32F4X_PIN_CONFIG_AF_PUSH_UP),
 };
 
-static const stm32_pin_func_t pin_pa0_funcs[] = {
-	[STM32F4_PINMUX_FUNC_PA0_PWM2_CH1 - 1] =
-			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+static const stm32_pin_func_t pin_pb7_funcs[] = {
+	PAD(STM32F4_PINMUX_FUNC_PB7_USART1_RX, STM32F4X_PIN_CONFIG_AF_PUSH_UP),
 };
 
 /**
  * @brief pin configuration
  */
 static const struct stm32_pinmux_conf pins[] = {
+	STM32_PIN_CONF(STM32_PIN_PA0, pin_pa0_funcs),
+	STM32_PIN_CONF(STM32_PIN_PA2, pin_pa2_funcs),
+	STM32_PIN_CONF(STM32_PIN_PA3, pin_pa3_funcs),
 	STM32_PIN_CONF(STM32_PIN_PA9, pin_pa9_funcs),
 	STM32_PIN_CONF(STM32_PIN_PA10, pin_pa10_funcs),
 	STM32_PIN_CONF(STM32_PIN_PB6, pin_pb6_funcs),
 	STM32_PIN_CONF(STM32_PIN_PB7, pin_pb7_funcs),
-	STM32_PIN_CONF(STM32_PIN_PA2, pin_pa2_funcs),
-	STM32_PIN_CONF(STM32_PIN_PA3, pin_pa3_funcs),
-	STM32_PIN_CONF(STM32_PIN_PA0, pin_pa0_funcs),
 };
 
 int stm32_get_pin_config(int pin, int func)