drivers/usb/gadget/function/u_serial.h

   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 */