// SPDX-License-Identifier: GPL-2.0+
/*
 * hid.c -- HID Composite driver
 *
 * Based on multi.c
 *
 * Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>
 */


#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/usb/composite.h>
#include <linux/usb/g_hid.h>

#define DRIVER_DESC		"HID Gadget"
#define DRIVER_VERSION		"2010/03/16"

#include "u_hid.h"

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

#define HIDG_VENDOR_NUM		0x0525	/* XXX NetChip */
#define HIDG_PRODUCT_NUM	0xa4ac	/* Linux-USB HID gadget */

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

struct hidg_func_node {
	struct usb_function_instance *fi;
	struct usb_function *f;
	struct list_head node;
	struct hidg_func_descriptor *func;
};

static LIST_HEAD(hidg_func_list);

/*-------------------------------------------------------------------------*/
USB_GADGET_COMPOSITE_OPTIONS();

static struct usb_device_descriptor device_desc = {
	.bLength =		sizeof device_desc,
	.bDescriptorType =	USB_DT_DEVICE,

	/* .bcdUSB = DYNAMIC */

	/* .bDeviceClass =		USB_CLASS_COMM, */
	/* .bDeviceSubClass =	0, */
	/* .bDeviceProtocol =	0, */
	.bDeviceClass =		USB_CLASS_PER_INTERFACE,
	.bDeviceSubClass =	0,
	.bDeviceProtocol =	0,
	/* .bMaxPacketSize0 = f(hardware) */

	/* Vendor and product id can be overridden by module parameters.  */
	.idVendor =		cpu_to_le16(HIDG_VENDOR_NUM),
	.idProduct =		cpu_to_le16(HIDG_PRODUCT_NUM),
	/* .bcdDevice = f(hardware) */
	/* .iManufacturer = DYNAMIC */
	/* .iProduct = DYNAMIC */
	/* NO SERIAL NUMBER */
	.bNumConfigurations =	1,
};

static const struct usb_descriptor_header *otg_desc[2];

/* string IDs are assigned dynamically */
static struct usb_string strings_dev[] = {
	[USB_GADGET_MANUFACTURER_IDX].s = "",
	[USB_GADGET_PRODUCT_IDX].s = DRIVER_DESC,
	[USB_GADGET_SERIAL_IDX].s = "",
	{  } /* 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,
};


/****************************** Configurations ******************************/

static int do_config(struct usb_configuration *c)
{
	struct hidg_func_node *e, *n;
	int status = 0;

	if (gadget_is_otg(c->cdev->gadget)) {
		c->descriptors = otg_desc;
		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
	}

	list_for_each_entry(e, &hidg_func_list, node) {
		e->f = usb_get_function(e->fi);
		if (IS_ERR(e->f))
			goto put;
		status = usb_add_function(c, e->f);
		if (status < 0) {
			usb_put_function(e->f);
			goto put;
		}
	}

	return 0;
put:
	list_for_each_entry(n, &hidg_func_list, node) {
		if (n == e)
			break;
		usb_remove_function(c, n->f);
		usb_put_function(n->f);
	}
	return status;
}

static struct usb_configuration config_driver = {
	.label			= "HID Gadget",
	.bConfigurationValue	= 1,
	/* .iConfiguration = DYNAMIC */
	.bmAttributes		= USB_CONFIG_ATT_SELFPOWER,
};

/****************************** Gadget Bind ******************************/

static int hid_bind(struct usb_composite_dev *cdev)
{
	struct usb_gadget *gadget = cdev->gadget;
	struct list_head *tmp;
	struct hidg_func_node *n, *m;
	struct f_hid_opts *hid_opts;
	int status, funcs = 0;

	list_for_each(tmp, &hidg_func_list)
		funcs++;

	if (!funcs)
		return -ENODEV;

	list_for_each_entry(n, &hidg_func_list, node) {
		n->fi = usb_get_function_instance("hid");
		if (IS_ERR(n->fi)) {
			status = PTR_ERR(n->fi);
			goto put;
		}
		hid_opts = container_of(n->fi, struct f_hid_opts, func_inst);
		hid_opts->subclass = n->func->subclass;
		hid_opts->protocol = n->func->protocol;
		hid_opts->report_length = n->func->report_length;
		hid_opts->report_desc_length = n->func->report_desc_length;
		hid_opts->report_desc = n->func->report_desc;
	}


	/* Allocate string descriptor numbers ... note that string
	 * contents can be overridden by the composite_dev glue.
	 */

	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;

	if (gadget_is_otg(gadget) && !otg_desc[0]) {
		struct usb_descriptor_header *usb_desc;

		usb_desc = usb_otg_descriptor_alloc(gadget);
		if (!usb_desc)
			goto put;
		usb_otg_descriptor_init(gadget, usb_desc);
		otg_desc[0] = usb_desc;
		otg_desc[1] = NULL;
	}

	/* register our configuration */
	status = usb_add_config(cdev, &config_driver, do_config);
	if (status < 0)
		goto free_otg_desc;

	usb_composite_overwrite_options(cdev, &coverwrite);
	dev_info(&gadget->dev, DRIVER_DESC ", version: " DRIVER_VERSION "\n");

	return 0;

free_otg_desc:
	kfree(otg_desc[0]);
	otg_desc[0] = NULL;
put:
	list_for_each_entry(m, &hidg_func_list, node) {
		if (m == n)
			break;
		usb_put_function_instance(m->fi);
	}
	return status;
}

static int hid_unbind(struct usb_composite_dev *cdev)
{
	struct hidg_func_node *n;

	list_for_each_entry(n, &hidg_func_list, node) {
		usb_put_function(n->f);
		usb_put_function_instance(n->fi);
	}

	kfree(otg_desc[0]);
	otg_desc[0] = NULL;

	return 0;
}

static int hidg_plat_driver_probe(struct platform_device *pdev)
{
	struct hidg_func_descriptor *func = dev_get_platdata(&pdev->dev);
	struct hidg_func_node *entry;

	if (!func) {
		dev_err(&pdev->dev, "Platform data missing\n");
		return -ENODEV;
	}

	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return -ENOMEM;

	entry->func = func;
	list_add_tail(&entry->node, &hidg_func_list);

	return 0;
}

static int hidg_plat_driver_remove(struct platform_device *pdev)
{
	struct hidg_func_node *e, *n;

	list_for_each_entry_safe(e, n, &hidg_func_list, node) {
		list_del(&e->node);
		kfree(e);
	}

	return 0;
}


/****************************** Some noise ******************************/


static struct usb_composite_driver hidg_driver = {
	.name		= "g_hid",
	.dev		= &device_desc,
	.strings	= dev_strings,
	.max_speed	= USB_SPEED_HIGH,
	.bind		= hid_bind,
	.unbind		= hid_unbind,
};

static struct platform_driver hidg_plat_driver = {
	.remove		= hidg_plat_driver_remove,
	.driver		= {
		.name	= "hidg",
	},
};


MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("Fabien Chouteau, Peter Korsgaard");
MODULE_LICENSE("GPL");

static int __init hidg_init(void)
{
	int status;

	status = platform_driver_probe(&hidg_plat_driver,
				hidg_plat_driver_probe);
	if (status < 0)
		return status;

	status = usb_composite_probe(&hidg_driver);
	if (status < 0)
		platform_driver_unregister(&hidg_plat_driver);

	return status;
}
module_init(hidg_init);

static void __exit hidg_cleanup(void)
{
	usb_composite_unregister(&hidg_driver);
	platform_driver_unregister(&hidg_plat_driver);
}
module_exit(hidg_cleanup);