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_LICENSE("GPL v2"); 35 36 static const char longname[] = "MIDI Gadget"; 37 38 USB_GADGET_COMPOSITE_OPTIONS(); 39 40 static int index = SNDRV_DEFAULT_IDX1; 41 module_param(index, int, S_IRUGO); 42 MODULE_PARM_DESC(index, "Index value for the USB MIDI Gadget adapter."); 43 44 static char *id = SNDRV_DEFAULT_STR1; 45 module_param(id, charp, S_IRUGO); 46 MODULE_PARM_DESC(id, "ID string for the USB MIDI Gadget adapter."); 47 48 static unsigned int buflen = 512; 49 module_param(buflen, uint, S_IRUGO); 50 MODULE_PARM_DESC(buflen, "MIDI buffer length"); 51 52 static unsigned int qlen = 32; 53 module_param(qlen, uint, S_IRUGO); 54 MODULE_PARM_DESC(qlen, "USB read and write request queue length"); 55 56 static unsigned int in_ports = 1; 57 module_param(in_ports, uint, S_IRUGO); 58 MODULE_PARM_DESC(in_ports, "Number of MIDI input ports"); 59 60 static unsigned int out_ports = 1; 61 module_param(out_ports, uint, S_IRUGO); 62 MODULE_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 76 static 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 88 static 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 96 static struct usb_gadget_strings stringtab_dev = { 97 .language = 0x0409, /* en-us */ 98 .strings = strings_dev, 99 }; 100 101 static struct usb_gadget_strings *dev_strings[] = { 102 &stringtab_dev, 103 NULL, 104 }; 105 106 static struct usb_function_instance *fi_midi; 107 static struct usb_function *f_midi; 108 109 static 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 } 115 116 static 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 }; 123 124 static 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 } 140 141 static 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; 171 put: 172 usb_put_function_instance(fi_midi); 173 return status; 174 } 175 176 static 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 }; 184 185 module_usb_composite_driver(midi_driver); 186