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,
