usb: gadget: make sure each gadget is using same index for Product, Serial,…

The index in usb_string array is defined by the gadget. The gadget can
choose which index entry it assigns for the serial number and which the
product name. The gadget has just to ensure that the descriptor contains
the proper string id which is assigned by composite.
If the composite layer knows the index of the "default" information
which will be overwritten by module parameters, it can be used later to
overwrite it.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/drivers/usb/gadget/gmidi.c b/drivers/usb/gadget/gmidi.c
index 01b31e2d03af..2ee3a74056c9 100644
--- a/drivers/usb/gadget/gmidi.c
+++ b/drivers/usb/gadget/gmidi.c
@@ -84,9 +84,7 @@ MODULE_PARM_DESC(out_ports, "Number of MIDI output ports");
 
 /* string IDs are assigned dynamically */
 
-#define STRING_MANUFACTURER_IDX         0
-#define STRING_PRODUCT_IDX              1
-#define STRING_DESCRIPTION_IDX          2
+#define STRING_DESCRIPTION_IDX          USB_GADGET_FIRST_AVAIL_IDX
 
 static struct usb_device_descriptor device_desc = {
         .bLength =              USB_DT_DEVICE_SIZE,
@@ -101,8 +99,9 @@ static struct usb_device_descriptor device_desc = {
 };
 
 static struct usb_string strings_dev[] = {
-        [STRING_MANUFACTURER_IDX].s     = "Grey Innovation",
-        [STRING_PRODUCT_IDX].s          = "MIDI Gadget",
+        [USB_GADGET_MANUFACTURER_IDX].s = "Grey Innovation",
+        [USB_GADGET_PRODUCT_IDX].s      = "MIDI Gadget",
+        [USB_GADGET_SERIAL_IDX].s       = "",
         [STRING_DESCRIPTION_IDX].s      = "MIDI",
         {  } /* end of list */
 };
@@ -145,8 +144,8 @@ static int __init midi_bind(struct usb_composite_dev *cdev)
         status = usb_string_ids_tab(cdev, strings_dev);
         if (status < 0)
                 return status;
-        device_desc.iManufacturer = strings_dev[STRING_MANUFACTURER_IDX].id;
-        device_desc.iProduct = strings_dev[STRING_PRODUCT_IDX].id;
+        device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
+        device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
         midi_config.iConfiguration = strings_dev[STRING_DESCRIPTION_IDX].id;
 
         gcnum = usb_gadget_controller_number(gadget);