static const struct uac_format_type_i_discrete_descriptor * find_format_descriptor(struct usb_interface *interface) { struct usb_host_interface *alt; u8 *extra; int extralen; if (interface->num_altsetting != 2) { dev_err(&interface->dev, "invalid num_altsetting\n"); return NULL; } alt = &interface->altsetting[0]; if (alt->desc.bNumEndpoints != 0) { dev_err(&interface->dev, "invalid bNumEndpoints\n"); return NULL; } alt = &interface->altsetting[1]; if (alt->desc.bNumEndpoints != 1) { dev_err(&interface->dev, "invalid bNumEndpoints\n"); return NULL; } extra = alt->extra; extralen = alt->extralen; while (extralen >= sizeof(struct usb_descriptor_header)) { struct uac_format_type_i_discrete_descriptor *desc; desc = (struct uac_format_type_i_discrete_descriptor *)extra; if (desc->bLength > extralen) { dev_err(&interface->dev, "descriptor overflow\n"); return NULL; } if (desc->bLength == UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1) && desc->bDescriptorType == USB_DT_CS_INTERFACE && desc->bDescriptorSubtype == UAC_FORMAT_TYPE) { if (desc->bFormatType != UAC_FORMAT_TYPE_I_PCM || desc->bSamFreqType != 1) { dev_err(&interface->dev, "invalid format type\n"); return NULL; } return desc; } extralen -= desc->bLength; extra += desc->bLength; } dev_err(&interface->dev, "sample format descriptor not found\n"); return NULL; }
.bInterfaceClass = USB_CLASS_AUDIO, .bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING, }; /* B.4.2 Class-Specific AS Interface Descriptor */ static struct uac1_as_header_descriptor speaker_as_header_desc = { .bLength = UAC_DT_AS_HEADER_SIZE, .bDescriptorType = USB_DT_CS_INTERFACE, .bDescriptorSubtype = UAC_AS_GENERAL, .bTerminalLink = SPEAKER_INPUT_TERMINAL_ID, .bDelay = 1, .wFormatTag = UAC_FORMAT_TYPE_I_PCM, }; static struct uac_format_type_i_discrete_descriptor_1 speaker_as_type_i_desc = { .bLength = UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1), .bDescriptorType = USB_DT_CS_INTERFACE, .bDescriptorSubtype = UAC_FORMAT_TYPE, .bFormatType = UAC_FORMAT_TYPE_I, .bSubframeSize = 2, .bBitResolution = 16, .bSamFreqType = 1, }; /* Standard ISO OUT Endpoint Descriptor */ static struct usb_endpoint_descriptor speaker_as_ep_out_desc = { .bLength = USB_DT_ENDPOINT_AUDIO_SIZE, .bDescriptorType = USB_DT_ENDPOINT, .bEndpointAddress = USB_DIR_OUT, .bmAttributes = USB_ENDPOINT_SYNC_ADAPTIVE | USB_ENDPOINT_XFER_ISOC,