skel_do_read
rv = skel_do_read(dev, buf, count);
static ssize_t skel_do_read(struct usb_skel *, char *, size_t);
nchar = skel_do_read(GPIB_DEV, buffer, 64);
b->nchar = skel_do_read(GPIB_DEV, b->inbuf, INBUF_SIZE);
retval = skel_do_read(GPIB_DEV, inbuf, 1);
retval += skel_do_read(GPIB_DEV, inbuf + 1, 1);