Simplify closing of device files

By treating PTT/DCD devices differently from rig control devices.

src/iofunc.c

@@ -185,8 +185,6 @@ int HAMLIB_API port_open(hamlib_port_t *p)
  * \param p rig port descriptor
  * \param port_type equivalent rig port type
  * \return status
- *
- * This function may also be used with ptt and dcd ports.
  */
 int HAMLIB_API port_close(hamlib_port_t *p, rig_port_t port_type)
 {
@@ -202,19 +200,6 @@ int HAMLIB_API port_close(hamlib_port_t *p, rig_port_t port_type)
             ret = ser_close(p);
             break;
 
-        case RIG_PORT_PARALLEL:
-            ret = par_close(p);
-            break;
-
-        case RIG_PORT_CM108:
-            ret = cm108_close(p);
-            break;
-
-        case RIG_PORT_GPIO:
-        case RIG_PORT_GPION:
-            ret = gpio_close(p);
-            break;
-
         case RIG_PORT_USB:
             ret = usb_port_close(p);
             break;

src/rig.c

@@ -703,7 +703,6 @@ int HAMLIB_API rig_open(RIG *rig)
         else
         {
             gpio_ptt_set(&rs->pttport, RIG_PTT_OFF);
-            gpio_close(&rs->pttport);
         }
 
         break;
@@ -776,9 +775,6 @@ int HAMLIB_API rig_open(RIG *rig)
                       rs->dcdport.pathname);
             status = -RIG_EIO;
         }
-        else {
-            gpio_close(&rs->dcdport);
-        }
 
         break;
 
@@ -933,18 +929,18 @@ int HAMLIB_API rig_close(RIG *rig)
 
     case RIG_PTT_PARALLEL:
         par_ptt_set(&rs->pttport, RIG_PTT_OFF);
-        port_close(&rs->pttport, RIG_PORT_PARALLEL);
+        par_close(&rs->pttport);
         break;
 
     case RIG_PTT_CM108:
         cm108_ptt_set(&rs->pttport, RIG_PTT_OFF);
-        port_close(&rs->pttport, RIG_PORT_CM108);
+        cm108_close(&rs->pttport);
         break;
 
     case RIG_PTT_GPIO:
     case RIG_PTT_GPION:
         gpio_ptt_set(&rs->pttport, RIG_PTT_OFF);
-        port_close(&rs->pttport, RIG_PORT_GPIO);
+        gpio_close(&rs->pttport);
         break;
 
     default:
@@ -971,12 +967,12 @@ int HAMLIB_API rig_close(RIG *rig)
         break;
 
     case RIG_DCD_PARALLEL:
-        port_close(&rs->dcdport, RIG_PORT_PARALLEL);
+        par_close(&rs->dcdport);
         break;
 
     case RIG_DCD_GPIO:
     case RIG_DCD_GPION:
-        port_close(&rs->dcdport, RIG_PORT_GPIO);
+        gpio_close(&rs->dcdport);
         break;
 
     default: