gmidi.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * gmidi.c -- USB MIDI Gadget Driver
  4 *
  5 * Copyright (C) 2006 Thumtronics Pty Ltd.
  6 * Developed for Thumtronics by Grey Innovation
  7 * Ben Williamson <ben.williamson@greyinnovation.com>
  8 *
  9 * This code is based in part on:
 10 *
 11 * Gadget Zero driver, Copyright (C) 2003-2004 David Brownell.
 12 * USB Audio driver, Copyright (C) 2002 by Takashi Iwai.
 13 * USB MIDI driver, Copyright (C) 2002-2005 Clemens Ladisch.
 14 *
 15 * Refer to the USB Device Class Definition for MIDI Devices:
 16 * http://www.usb.org/developers/devclass_docs/midi10.pdf
 17 */
 18
 19/* #define VERBOSE_DEBUG */
 20
 21#include <linux/kernel.h>
 22#include <linux/module.h>
 23
 24#include <sound/initval.h>
 25
 26#include <linux/usb/composite.h>
 27#include <linux/usb/gadget.h>
 28
 29#include "u_midi.h"
 30
 31/*-------------------------------------------------------------------------*/
 32
 33MODULE_AUTHOR("Ben Williamson");
 34MODULE_DESCRIPTION("USB MIDI Gadget Driver");
 35MODULE_LICENSE("GPL v2");
 36
 37static const char longname[] = "MIDI Gadget";
 38
 39USB_GADGET_COMPOSITE_OPTIONS();
 40
 41static int index = SNDRV_DEFAULT_IDX1;
 42module_param(index, int, S_IRUGO);
 43MODULE_PARM_DESC(index, "Index value for the USB MIDI Gadget adapter.");
 44
 45static char *id = SNDRV_DEFAULT_STR1;
 46module_param(id, charp, S_IRUGO);
 47MODULE_PARM_DESC(id, "ID string for the USB MIDI Gadget adapter.");
 48
 49static unsigned int buflen = 512;
 50module_param(buflen, uint, S_IRUGO);
 51MODULE_PARM_DESC(buflen, "MIDI buffer length");
 52
 53static unsigned int qlen = 32;
 54module_param(qlen, uint, S_IRUGO);
 55MODULE_PARM_DESC(qlen, "USB read and write request queue length");
 56
 57static unsigned int in_ports = 1;
 58module_param(in_ports, uint, S_IRUGO);
 59MODULE_PARM_DESC(in_ports, "Number of MIDI input ports");
 60
 61static unsigned int out_ports = 1;
 62module_param(out_ports, uint, S_IRUGO);
 63MODULE_PARM_DESC(out_ports, "Number of MIDI output ports");
 64
 65/* Thanks to Grey Innovation for donating this product ID.
 66 *
 67 * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
 68 * Instead:  allocate your own, using normal USB-IF procedures.
 69 */
 70#define DRIVER_VENDOR_NUM	0x17b3		/* Grey Innovation */
 71#define DRIVER_PRODUCT_NUM	0x0004		/* Linux-USB "MIDI Gadget" */
 72
 73/* string IDs are assigned dynamically */
 74
 75#define STRING_DESCRIPTION_IDX		USB_GADGET_FIRST_AVAIL_IDX
 76
 77static struct usb_device_descriptor device_desc = {
 78	.bLength =		USB_DT_DEVICE_SIZE,
 79	.bDescriptorType =	USB_DT_DEVICE,
 80	/* .bcdUSB = DYNAMIC */
 81	.bDeviceClass =		USB_CLASS_PER_INTERFACE,
 82	.idVendor =		cpu_to_le16(DRIVER_VENDOR_NUM),
 83	.idProduct =		cpu_to_le16(DRIVER_PRODUCT_NUM),
 84	/* .iManufacturer =	DYNAMIC */
 85	/* .iProduct =		DYNAMIC */
 86	.bNumConfigurations =	1,
 87};
 88
 89static struct usb_string strings_dev[] = {
 90	[USB_GADGET_MANUFACTURER_IDX].s	= "Grey Innovation",
 91	[USB_GADGET_PRODUCT_IDX].s	= "MIDI Gadget",
 92	[USB_GADGET_SERIAL_IDX].s	= "",
 93	[STRING_DESCRIPTION_IDX].s	= "MIDI",
 94	{  } /* end of list */
 95};
 96
 97static struct usb_gadget_strings stringtab_dev = {
 98	.language	= 0x0409,	/* en-us */
 99	.strings	= strings_dev,
100};
101
102static struct usb_gadget_strings *dev_strings[] = {
103	&stringtab_dev,
104	NULL,
105};
106
107static struct usb_function_instance *fi_midi;
108static struct usb_function *f_midi;
109
110static int midi_unbind(struct usb_composite_dev *dev)
111{
112	usb_put_function(f_midi);
113	usb_put_function_instance(fi_midi);
114	return 0;
115}
116
117static struct usb_configuration midi_config = {
118	.label		= "MIDI Gadget",
119	.bConfigurationValue = 1,
120	/* .iConfiguration = DYNAMIC */
121	.bmAttributes	= USB_CONFIG_ATT_ONE,
122	.MaxPower	= CONFIG_USB_GADGET_VBUS_DRAW,
123};
124
125static int midi_bind_config(struct usb_configuration *c)
126{
127	int status;
128
129	f_midi = usb_get_function(fi_midi);
130	if (IS_ERR(f_midi))
131		return PTR_ERR(f_midi);
132
133	status = usb_add_function(c, f_midi);
134	if (status < 0) {
135		usb_put_function(f_midi);
136		return status;
137	}
138
139	return 0;
140}
141
142static int midi_bind(struct usb_composite_dev *cdev)
143{
144	struct f_midi_opts *midi_opts;
145	int status;
146
147	fi_midi = usb_get_function_instance("midi");
148	if (IS_ERR(fi_midi))
149		return PTR_ERR(fi_midi);
150
151	midi_opts = container_of(fi_midi, struct f_midi_opts, func_inst);
152	midi_opts->index = index;
153	midi_opts->id = id;
154	midi_opts->in_ports = in_ports;
155	midi_opts->out_ports = out_ports;
156	midi_opts->buflen = buflen;
157	midi_opts->qlen = qlen;
158
159	status = usb_string_ids_tab(cdev, strings_dev);
160	if (status < 0)
161		goto put;
162	device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
163	device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
164	midi_config.iConfiguration = strings_dev[STRING_DESCRIPTION_IDX].id;
165
166	status = usb_add_config(cdev, &midi_config, midi_bind_config);
167	if (status < 0)
168		goto put;
169	usb_composite_overwrite_options(cdev, &coverwrite);
170	pr_info("%s\n", longname);
171	return 0;
172put:
173	usb_put_function_instance(fi_midi);
174	return status;
175}
176
177static struct usb_composite_driver midi_driver = {
178	.name		= longname,
179	.dev		= &device_desc,
180	.strings	= dev_strings,
181	.max_speed	= USB_SPEED_HIGH,
182	.bind		= midi_bind,
183	.unbind		= midi_unbind,
184};
185
186module_usb_composite_driver(midi_driver);