drivers/usb/gadget/legacy/gmidi.c

Source file repositories/reference/linux-study-clean/drivers/usb/gadget/legacy/gmidi.c

File Facts

System
Linux kernel
Corpus path
drivers/usb/gadget/legacy/gmidi.c
Extension
.c
Size
4999 bytes
Lines
187
Domain
Driver Families
Bucket
drivers/usb
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 * gmidi.c -- USB MIDI Gadget Driver
 *
 * Copyright (C) 2006 Thumtronics Pty Ltd.
 * Developed for Thumtronics by Grey Innovation
 * Ben Williamson <ben.williamson@greyinnovation.com>
 *
 * This code is based in part on:
 *
 * Gadget Zero driver, Copyright (C) 2003-2004 David Brownell.
 * USB Audio driver, Copyright (C) 2002 by Takashi Iwai.
 * USB MIDI driver, Copyright (C) 2002-2005 Clemens Ladisch.
 *
 * Refer to the USB Device Class Definition for MIDI Devices:
 * http://www.usb.org/developers/devclass_docs/midi10.pdf
 */

/* #define VERBOSE_DEBUG */

#include <linux/kernel.h>
#include <linux/module.h>

#include <sound/initval.h>

#include <linux/usb/composite.h>
#include <linux/usb/gadget.h>

#include "u_midi.h"

/*-------------------------------------------------------------------------*/

MODULE_AUTHOR("Ben Williamson");
MODULE_DESCRIPTION("USB MIDI Gadget Driver");
MODULE_LICENSE("GPL v2");

static const char longname[] = "MIDI Gadget";

USB_GADGET_COMPOSITE_OPTIONS();

static int index = SNDRV_DEFAULT_IDX1;
module_param(index, int, S_IRUGO);
MODULE_PARM_DESC(index, "Index value for the USB MIDI Gadget adapter.");

static char *id = SNDRV_DEFAULT_STR1;
module_param(id, charp, S_IRUGO);
MODULE_PARM_DESC(id, "ID string for the USB MIDI Gadget adapter.");

static unsigned int buflen = 512;
module_param(buflen, uint, S_IRUGO);
MODULE_PARM_DESC(buflen, "MIDI buffer length");

static unsigned int qlen = 32;
module_param(qlen, uint, S_IRUGO);
MODULE_PARM_DESC(qlen, "USB read and write request queue length");

static unsigned int in_ports = 1;
module_param(in_ports, uint, S_IRUGO);
MODULE_PARM_DESC(in_ports, "Number of MIDI input ports");

static unsigned int out_ports = 1;
module_param(out_ports, uint, S_IRUGO);
MODULE_PARM_DESC(out_ports, "Number of MIDI output ports");

/* Thanks to Grey Innovation for donating this product ID.
 *
 * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
 * Instead:  allocate your own, using normal USB-IF procedures.
 */
#define DRIVER_VENDOR_NUM	0x17b3		/* Grey Innovation */
#define DRIVER_PRODUCT_NUM	0x0004		/* Linux-USB "MIDI Gadget" */

/* string IDs are assigned dynamically */

#define STRING_DESCRIPTION_IDX		USB_GADGET_FIRST_AVAIL_IDX

static struct usb_device_descriptor device_desc = {
	.bLength =		USB_DT_DEVICE_SIZE,
	.bDescriptorType =	USB_DT_DEVICE,
	/* .bcdUSB = DYNAMIC */
	.bDeviceClass =		USB_CLASS_PER_INTERFACE,
	.idVendor =		cpu_to_le16(DRIVER_VENDOR_NUM),
	.idProduct =		cpu_to_le16(DRIVER_PRODUCT_NUM),
	/* .iManufacturer =	DYNAMIC */
	/* .iProduct =		DYNAMIC */
	.bNumConfigurations =	1,
};

static struct usb_string strings_dev[] = {
	[USB_GADGET_MANUFACTURER_IDX].s	= "Grey Innovation",

Annotation

Implementation Notes