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_LICENSE("GPL v2");
35
36static const char longname[] = "MIDI Gadget";
37
38USB_GADGET_COMPOSITE_OPTIONS();
39
40static int index = SNDRV_DEFAULT_IDX1;
41module_param(index, int, S_IRUGO);
42MODULE_PARM_DESC(index, "Index value for the USB MIDI Gadget adapter.");
43
44static char *id = SNDRV_DEFAULT_STR1;
45module_param(id, charp, S_IRUGO);
46MODULE_PARM_DESC(id, "ID string for the USB MIDI Gadget adapter.");
47
48static unsigned int buflen = 512;
49module_param(buflen, uint, S_IRUGO);
50MODULE_PARM_DESC(buflen, "MIDI buffer length");
51
52static unsigned int qlen = 32;
53module_param(qlen, uint, S_IRUGO);
54MODULE_PARM_DESC(qlen, "USB read and write request queue length");
55
56static unsigned int in_ports = 1;
57module_param(in_ports, uint, S_IRUGO);
58MODULE_PARM_DESC(in_ports, "Number of MIDI input ports");
59
60static unsigned int out_ports = 1;
61module_param(out_ports, uint, S_IRUGO);
62MODULE_PARM_DESC(out_ports, "Number of MIDI output ports");
63
64/* Thanks to Grey Innovation for donating this product ID.
65 *
66 * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
67 * Instead:  allocate your own, using normal USB-IF procedures.
68 */
69#define DRIVER_VENDOR_NUM	0x17b3		/* Grey Innovation */
70#define DRIVER_PRODUCT_NUM	0x0004		/* Linux-USB "MIDI Gadget" */
71
72/* string IDs are assigned dynamically */
73
74#define STRING_DESCRIPTION_IDX		USB_GADGET_FIRST_AVAIL_IDX
75
76static struct usb_device_descriptor device_desc = {
77	.bLength =		USB_DT_DEVICE_SIZE,
78	.bDescriptorType =	USB_DT_DEVICE,
79	/* .bcdUSB = DYNAMIC */
80	.bDeviceClass =		USB_CLASS_PER_INTERFACE,
81	.idVendor =		cpu_to_le16(DRIVER_VENDOR_NUM),
82	.idProduct =		cpu_to_le16(DRIVER_PRODUCT_NUM),
83	/* .iManufacturer =	DYNAMIC */
84	/* .iProduct =		DYNAMIC */
85	.bNumConfigurations =	1,
86};
87
88static struct usb_string strings_dev[] = {
89	[USB_GADGET_MANUFACTURER_IDX].s	= "Grey Innovation",
90	[USB_GADGET_PRODUCT_IDX].s	= "MIDI Gadget",
91	[USB_GADGET_SERIAL_IDX].s	= "",
92	[STRING_DESCRIPTION_IDX].s	= "MIDI",
93	{  } /* end of list */
94};
95
96static struct usb_gadget_strings stringtab_dev = {
97	.language	= 0x0409,	/* en-us */
98	.strings	= strings_dev,
99};
100
101static struct usb_gadget_strings *dev_strings[] = {
102	&stringtab_dev,
103	NULL,
104};
105
106static struct usb_function_instance *fi_midi;
107static struct usb_function *f_midi;
108
109static int midi_unbind(struct usb_composite_dev *dev)
110{
111	usb_put_function(f_midi);
112	usb_put_function_instance(fi_midi);
113	return 0;
114}
115
116static struct usb_configuration midi_config = {
117	.label		= "MIDI Gadget",
118	.bConfigurationValue = 1,
119	/* .iConfiguration = DYNAMIC */
120	.bmAttributes	= USB_CONFIG_ATT_ONE,
121	.MaxPower	= CONFIG_USB_GADGET_VBUS_DRAW,
122};
123
124static int midi_bind_config(struct usb_configuration *c)
125{
126	int status;
127
128	f_midi = usb_get_function(fi_midi);
129	if (IS_ERR(f_midi))
130		return PTR_ERR(f_midi);
131
132	status = usb_add_function(c, f_midi);
133	if (status < 0) {
134		usb_put_function(f_midi);
135		return status;
136	}
137
138	return 0;
139}
140
141static int midi_bind(struct usb_composite_dev *cdev)
142{
143	struct f_midi_opts *midi_opts;
144	int status;
145
146	fi_midi = usb_get_function_instance("midi");
147	if (IS_ERR(fi_midi))
148		return PTR_ERR(fi_midi);
149
150	midi_opts = container_of(fi_midi, struct f_midi_opts, func_inst);
151	midi_opts->index = index;
152	midi_opts->id = id;
153	midi_opts->in_ports = in_ports;
154	midi_opts->out_ports = out_ports;
155	midi_opts->buflen = buflen;
156	midi_opts->qlen = qlen;
157
158	status = usb_string_ids_tab(cdev, strings_dev);
159	if (status < 0)
160		goto put;
161	device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
162	device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
163	midi_config.iConfiguration = strings_dev[STRING_DESCRIPTION_IDX].id;
164
165	status = usb_add_config(cdev, &midi_config, midi_bind_config);
166	if (status < 0)
167		goto put;
168	usb_composite_overwrite_options(cdev, &coverwrite);
169	pr_info("%s\n", longname);
170	return 0;
171put:
172	usb_put_function_instance(fi_midi);
173	return status;
174}
175
176static struct usb_composite_driver midi_driver = {
177	.name		= longname,
178	.dev		= &device_desc,
179	.strings	= dev_strings,
180	.max_speed	= USB_SPEED_HIGH,
181	.bind		= midi_bind,
182	.unbind		= midi_unbind,
183};
184
185module_usb_composite_driver(midi_driver);
186