// 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",
        [USB_GADGET_PRODUCT_IDX].s      = "MIDI Gadget",
        [USB_GADGET_SERIAL_IDX].s       = "",
        [STRING_DESCRIPTION_IDX].s      = "MIDI",
        {  } /* end of list */
};

static struct usb_gadget_strings stringtab_dev = {
        .language       = 0x0409,       /* en-us */
        .strings        = strings_dev,
};

static struct usb_gadget_strings *dev_strings[] = {
        &stringtab_dev,
        NULL,
};

static struct usb_function_instance *fi_midi;
static struct usb_function *f_midi;

static int midi_unbind(struct usb_composite_dev *dev)
{
        usb_put_function(f_midi);
        usb_put_function_instance(fi_midi);
        return 0;
}

static struct usb_configuration midi_config = {
        .label          = "MIDI Gadget",
        .bConfigurationValue = 1,
        /* .iConfiguration = DYNAMIC */
        .bmAttributes   = USB_CONFIG_ATT_ONE,
        .MaxPower       = CONFIG_USB_GADGET_VBUS_DRAW,
};

static int midi_bind_config(struct usb_configuration *c)
{
        int status;

        f_midi = usb_get_function(fi_midi);
        if (IS_ERR(f_midi))
                return PTR_ERR(f_midi);

        status = usb_add_function(c, f_midi);
        if (status < 0) {
                usb_put_function(f_midi);
                return status;
        }

        return 0;
}

static int midi_bind(struct usb_composite_dev *cdev)
{
        struct f_midi_opts *midi_opts;
        int status;

        fi_midi = usb_get_function_instance("midi");
        if (IS_ERR(fi_midi))
                return PTR_ERR(fi_midi);

        midi_opts = container_of(fi_midi, struct f_midi_opts, func_inst);
        midi_opts->index = index;
        midi_opts->id = id;
        midi_opts->in_ports = in_ports;
        midi_opts->out_ports = out_ports;
        midi_opts->buflen = buflen;
        midi_opts->qlen = qlen;

        status = usb_string_ids_tab(cdev, strings_dev);
        if (status < 0)
                goto put;
        device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
        device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
        midi_config.iConfiguration = strings_dev[STRING_DESCRIPTION_IDX].id;

        status = usb_add_config(cdev, &midi_config, midi_bind_config);
        if (status < 0)
                goto put;
        usb_composite_overwrite_options(cdev, &coverwrite);
        pr_info("%s\n", longname);
        return 0;
put:
        usb_put_function_instance(fi_midi);
        return status;
}

static struct usb_composite_driver midi_driver = {
        .name           = longname,
        .dev            = &device_desc,
        .strings        = dev_strings,
        .max_speed      = USB_SPEED_HIGH,
        .bind           = midi_bind,
        .unbind         = midi_unbind,
};

module_usb_composite_driver(midi_driver);