F7 Slim: Support /DSKCHG signal as "pin 34"

src/mcu/stm32f7/board.c

@@ -213,7 +213,7 @@ static void mcu_board_init(void)
     case F7SM_slim:
         /* Extra pins should float in case they are inputs (drive->GW). */
         pu[_B] &= ~((1u << 0) | (1u << 12)); /* PB0, PB12 */
-        pu[_C] &= ~(1u << 8); /* PC8 */
+        pu[_C] &= ~((1u << 7) | ~(1u << 8)); /* PC7, PC8 */
         break;
 
     case F7SM_v3:

src/mcu/stm32f7/floppy.c

@@ -164,6 +164,12 @@ static uint8_t mcu_get_floppy_pin(unsigned int pin, uint8_t *p_level)
             return ACK_OKAY;
         }
         break;
+    case F7SM_slim:
+        if (pin == 34) {
+            *p_level = gpio_read_pin(gpioc, 7);
+            return ACK_OKAY;
+        }
+        break;
     }
     return ACK_BAD_PIN;
 }