fcp_init
#define FCP_IOCTL_INIT _IOWR('S', 0x64, struct fcp_init)
static int fcp_init(struct usb_mixer_interface *mixer,
return fcp_init(mixer, step0_resp, step2_resp);
struct fcp_init __user *arg)
struct fcp_init init;
err = fcp_init(mixer, resp, step2_resp);