Add 3rd Gen 18i8/18i20 S/PDIF/Digital I/O Mode startup controls

src/window-startup.c

@@ -7,6 +7,7 @@
 #include "scarlett2.h"
 #include "scarlett2-ioctls.h"
 #include "widget-boolean.h"
+#include "widget-drop-down.h"
 #include "window-startup.h"
 
 #define REQUIRED_HWDEP_VERSION_MAJOR 1
@@ -156,6 +157,60 @@ static int add_msd_control(
   return 1;
 }
 
+static int add_spdif_mode_control(
+  GArray    *elems,
+  GtkWidget *grid,
+  int       *grid_y
+) {
+  const char * const mode_names[] = {
+    "S/PDIF Mode",
+    "Digital I/O Mode",
+    NULL
+  };
+
+  struct alsa_elem *spdif = NULL;
+  int i = 0;
+
+  while (mode_names[i]) {
+    if ((spdif = get_elem_by_prefix(elems, mode_names[i])))
+      break;
+
+    i++;
+  }
+
+  if (!spdif)
+    return 0;
+
+  add_sep(grid, grid_y);
+
+  GtkWidget *w;
+
+  w = small_label(mode_names[i]);
+  gtk_grid_attach(GTK_GRID(grid), w, 0, *grid_y, 1, 1);
+
+  w = make_drop_down_alsa_elem(spdif, NULL);
+  gtk_widget_set_valign(w, GTK_ALIGN_START);
+  gtk_grid_attach(GTK_GRID(grid), w, 0, *grid_y + 1, 1, 1);
+
+  w = big_label(
+    i == 0 ? (
+      "The S/PDIF Mode selects whether the interface can receive "
+      "S/PDIF input from the coaxial (RCA) input or the optical "
+      "(TOSLINK) input. This requires a reboot to take effect."
+    ) : (
+      "The Digital I/O Mode selects whether the interface can "
+      "receive S/PDIF input from the coaxial (RCA) input, the "
+      "optical (TOSLINK) input, or whether dual-ADAT mode is "
+      "enabled. This requires a reboot to take effect."
+    )
+  );
+  gtk_grid_attach(GTK_GRID(grid), w, 1, *grid_y, 1, 2);
+
+  *grid_y += 2;
+
+  return 1;
+}
+
 static void add_reset_action(
   struct alsa_card *card,
   GtkWidget        *grid,
@@ -204,7 +259,7 @@ static void add_reset_actions(
   struct alsa_card *card,
   GtkWidget        *grid,
   int              *grid_y,
-  int               has_msd
+  int               show_reboot_option
 ) {
   // simulated cards don't support hwdep
   if (!card->device)
@@ -238,16 +293,17 @@ static void add_reset_actions(
 
   scarlett2_close(hwdep);
 
-  // Add reboot action if there is an MSD control
-  if (has_msd) {
+  // Add reboot action if there is a control that requires a reboot
+  // to take effect
+  if (show_reboot_option) {
     add_reset_action(
       card,
       grid,
       grid_y,
       "Reboot Device",
       "Reboot",
-      "After enabling or disabling MSD mode, the interface must be "
-      "rebooted for the change to take effect.",
+      "Rebooting the interface will apply changes made to the "
+      "startup configuration. This will take a few seconds.",
       G_CALLBACK(reboot_device)
     );
   }
@@ -323,7 +379,9 @@ GtkWidget *create_startup_controls(struct alsa_card *card) {
   add_standalone_control(elems, grid, &grid_y);
   add_phantom_persistence_control(elems, grid, &grid_y);
   int has_msd = add_msd_control(elems, grid, &grid_y);
-  add_reset_actions(card, grid, &grid_y, has_msd);
+  int has_spdif_mode = add_spdif_mode_control(elems, grid, &grid_y);
+  int show_reboot_option = has_msd || has_spdif_mode;
+  add_reset_actions(card, grid, &grid_y, show_reboot_option);
 
   if (!grid_y)
     add_no_startup_controls_msg(grid);