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
33 MODULE_AUTHOR("Ben Williamson");
34 MODULE_DESCRIPTION("USB MIDI Gadget Driver");
35 MODULE_LICENSE("GPL v2");
36
37 static const char longname[] = "MIDI Gadget";
38
39 USB_GADGET_COMPOSITE_OPTIONS();
40
41 static int index = SNDRV_DEFAULT_IDX1;
42 module_param(index, int, S_IRUGO);
43 MODULE_PARM_DESC(index, "Index value for the USB MIDI Gadget adapter.");
44
45 static char *id = SNDRV_DEFAULT_STR1;
46 module_param(id, charp, S_IRUGO);
47 MODULE_PARM_DESC(id, "ID string for the USB MIDI Gadget adapter.");
48
49 static unsigned int buflen = 512;
50 module_param(buflen, uint, S_IRUGO);
51 MODULE_PARM_DESC(buflen, "MIDI buffer length");
52
53 static unsigned int qlen = 32;
54 module_param(qlen, uint, S_IRUGO);
55 MODULE_PARM_DESC(qlen, "USB read and write request queue length");
56
57 static unsigned int in_ports = 1;
58 module_param(in_ports, uint, S_IRUGO);
59 MODULE_PARM_DESC(in_ports, "Number of MIDI input ports");
60
61 static unsigned int out_ports = 1;
62 module_param(out_ports, uint, S_IRUGO);
63 MODULE_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
77 static 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
89 static 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
97 static struct usb_gadget_strings stringtab_dev = {
98 .language = 0x0409, /* en-us */
99 .strings = strings_dev,
100 };
101
102 static struct usb_gadget_strings *dev_strings[] = {
103 &stringtab_dev,
104 NULL,
105 };
106
107 static struct usb_function_instance *fi_midi;
108 static struct usb_function *f_midi;
109
midi_unbind(struct usb_composite_dev * dev)110 static 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
117 static 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
midi_bind_config(struct usb_configuration * c)125 static 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
midi_bind(struct usb_composite_dev * cdev)142 static 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;
172 put:
173 usb_put_function_instance(fi_midi);
174 return status;
175 }
176
177 static 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
186 module_usb_composite_driver(midi_driver);
187