1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * u_serial.h - interface to USB gadget "serial port"/TTY utilities
4 *
5 * Copyright (C) 2008 David Brownell
6 * Copyright (C) 2008 by Nokia Corporation
7 */
8
9 #ifndef __U_SERIAL_H
10 #define __U_SERIAL_H
11
12 #include <linux/usb/composite.h>
13 #include <linux/usb/cdc.h>
14
15 #define MAX_U_SERIAL_PORTS 4
16
17 struct f_serial_opts {
18 struct usb_function_instance func_inst;
19 u8 port_num;
20 };
21
22 /*
23 * One non-multiplexed "serial" I/O port ... there can be several of these
24 * on any given USB peripheral device, if it provides enough endpoints.
25 *
26 * The "u_serial" utility component exists to do one thing: manage TTY
27 * style I/O using the USB peripheral endpoints listed here, including
28 * hookups to sysfs and /dev for each logical "tty" device.
29 *
30 * REVISIT at least ACM could support tiocmget() if needed.
31 *
32 * REVISIT someday, allow multiplexing several TTYs over these endpoints.
33 */
34 struct gserial {
35 struct usb_function func;
36
37 /* port is managed by gserial_{connect,disconnect} */
38 struct gs_port *ioport;
39
40 struct usb_ep *in;
41 struct usb_ep *out;
42
43 /* REVISIT avoid this CDC-ACM support harder ... */
44 struct usb_cdc_line_coding port_line_coding; /* 9600-8-N-1 etc */
45
46 /* notification callbacks */
47 void (*connect)(struct gserial *p);
48 void (*disconnect)(struct gserial *p);
49 int (*send_break)(struct gserial *p, int duration);
50 };
51
52 /* utilities to allocate/free request and buffer */
53 struct usb_request *gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t flags);
54 void gs_free_req(struct usb_ep *, struct usb_request *req);
55
56 /* management of individual TTY ports */
57 int gserial_alloc_line(unsigned char *port_line);
58 void gserial_free_line(unsigned char port_line);
59
60 /* connect/disconnect is handled by individual functions */
61 int gserial_connect(struct gserial *, u8 port_num);
62 void gserial_disconnect(struct gserial *);
63
64 /* functions are bound to configurations by a config or gadget driver */
65 int gser_bind_config(struct usb_configuration *c, u8 port_num);
66 int obex_bind_config(struct usb_configuration *c, u8 port_num);
67
68 #endif /* __U_SERIAL_H */