usb: gadget: f_uvc: use usb_gstrings_attach

Attach strings to gadget with usb_strings_attach.
It is required for correct instantiation of functions more than once:
instead of modifying the local uvc_en_us_strings a function instance
specific copy is created with usb_gstrings_attach.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 1eff416..95dc1c6 100644 (file)
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -562,6 +562,7 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 {
        struct usb_composite_dev *cdev = c->cdev;
        struct uvc_device *uvc = to_uvc(f);
+       struct usb_string *us;
        unsigned int max_packet_mult;
        unsigned int max_packet_size;
        struct usb_ep *ep;
@@ -637,22 +638,17 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
        uvc_hs_streaming_ep.bEndpointAddress = uvc->video.ep->address;
        uvc_ss_streaming_ep.bEndpointAddress = uvc->video.ep->address;
 
-       /* String descriptors are global, we only need to allocate string IDs
-        * for the first UVC function. UVC functions beyond the first (if any)
-        * will reuse the same IDs.
-        */
-       if (uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id == 0) {
-               ret = usb_string_ids_tab(c->cdev, uvc_en_us_strings);
-               if (ret)
-                       goto error;
-               uvc_iad.iFunction =
-                       uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id;
-               uvc_control_intf.iInterface =
-                       uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id;
-               ret = uvc_en_us_strings[UVC_STRING_STREAMING_IDX].id;
-               uvc_streaming_intf_alt0.iInterface = ret;
-               uvc_streaming_intf_alt1.iInterface = ret;
+       us = usb_gstrings_attach(cdev, uvc_function_strings,
+                                ARRAY_SIZE(uvc_en_us_strings));
+       if (IS_ERR(us)) {
+               ret = PTR_ERR(us);
+               goto error;
        }
+       uvc_iad.iFunction = us[UVC_STRING_CONTROL_IDX].id;
+       uvc_control_intf.iInterface = us[UVC_STRING_CONTROL_IDX].id;
+       ret = us[UVC_STRING_STREAMING_IDX].id;
+       uvc_streaming_intf_alt0.iInterface = ret;
+       uvc_streaming_intf_alt1.iInterface = ret;
 
        /* Allocate interface IDs. */
        if ((ret = usb_interface_id(c, f)) < 0)
@@ -771,7 +767,6 @@ static void uvc_unbind(struct usb_configuration *c, struct usb_function *f)
        uvc->control_ep->driver_data = NULL;
        uvc->video.ep->driver_data = NULL;
 
-       uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id = 0;
        usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
        kfree(uvc->control_buf);
 
@@ -798,7 +793,6 @@ struct usb_function *uvc_alloc(struct usb_function_instance *fi)
 
        /* Register the function. */
        uvc->func.name = "uvc";
-       uvc->func.strings = uvc_function_strings;
        uvc->func.bind = uvc_function_bind;
        uvc->func.unbind = uvc_unbind;
        uvc->func.get_alt = uvc_function_get_alt;