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; 109 110 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 }; 124 125 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 } 141 142 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