stm32f0: SPI and i2c interfaces added

Signed-off-by: Eugene Krashtan <eug.krashtan@gmail.com>

src/stm32f0/gpio.c

@@ -51,6 +51,7 @@ uint8_t const avail_pins[] = {
 static uint8_t
 gpio_check_pin(uint8_t pin)
 {
+    gpio_check_busy(pin);
     int i;
     for(i=0; i<ARRAY_SIZE(avail_pins); i++) {
         if (avail_pins[i] == pin)
@@ -139,3 +140,22 @@ void gpio_init(void)
     __HAL_RCC_GPIOB_CLK_ENABLE();
     __HAL_RCC_GPIOF_CLK_ENABLE();
 }
+
+void gpio_check_busy(uint8_t pin)
+{
+    // Increase to uint32_t and assert <32 on bigger chips
+    static uint16_t pinmap;
+    assert_param(sizeof(avail_pins)<16);
+
+    for (int i = 0; i<sizeof(avail_pins); i++) {
+        if(avail_pins[i]==pin) {
+            if(pinmap&(1<<i)) {
+                break;
+            } else {
+                pinmap |= 1<<i;
+                return;
+            }
+        }
+    }
+    shutdown("GPIO check failed");
+}