--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _LINUX_TTY_H
+#define _LINUX_TTY_H
+
+/*
+ * 'tty.h' defines some structures used by tty_io.c and some defines.
+ */
+
+#define NR_LDISCS 30
+
+/* line disciplines */
+#define N_TTY 0
+#define N_SLIP 1
+#define N_MOUSE 2
+#define N_PPP 3
+#define N_STRIP 4
+#define N_AX25 5
+#define N_X25 6 /* X.25 async */
+#define N_6PACK 7
+#define N_MASC 8 /* Reserved for Mobitex module <kaz@cafe.net> */
+#define N_R3964 9 /* Reserved for Simatic R3964 module */
+#define N_PROFIBUS_FDL 10 /* Reserved for Profibus */
+#define N_IRDA 11 /* Linux IrDa - http://irda.sourceforge.net/ */
+#define N_SMSBLOCK 12 /* SMS block mode - for talking to GSM data */
+ /* cards about SMS messages */
+#define N_HDLC 13 /* synchronous HDLC */
+#define N_SYNC_PPP 14 /* synchronous PPP */
+#define N_HCI 15 /* Bluetooth HCI UART */
+#define N_GIGASET_M101 16 /* Siemens Gigaset M101 serial DECT adapter */
+#define N_SLCAN 17 /* Serial / USB serial CAN Adaptors */
+#define N_PPS 18 /* Pulse per Second */
+#define N_V253 19 /* Codec control over voice modem */
+#define N_CAIF 20 /* CAIF protocol for talking to modems */
+#define N_GSM0710 21 /* GSM 0710 Mux */
+#define N_TI_WL 22 /* for TI's WL BT, FM, GPS combo chips */
+#define N_TRACESINK 23 /* Trace data routing for MIPI P1149.7 */
+#define N_TRACEROUTER 24 /* Trace data routing for MIPI P1149.7 */
+#define N_NCI 25 /* NFC NCI UART */
+#define N_SPEAKUP 26 /* Speakup communication with synths */
+#define N_NULL 27 /* Null ldisc used for error handling */
+
+#endif /* _LINUX_TTY_H */