nop-usb-xceiv.c

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/*
 * drivers/usb/otg/nop-usb-xceiv.c
 *
 * NOP USB transceiver for all USB transceiver which are either built-in
 * into USB IP or which are mostly autonomous.
 *
 * Copyright (C) 2009 Texas Instruments Inc
 * Author: Ajay Kumar Gupta <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Current status:
 *  This provides a "nop" transceiver for PHYs which are
 *  autonomous such as isp1504, isp1707, etc.
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/usb/otg.h>
#include <linux/usb/nop-usb-xceiv.h>
#include <linux/slab.h>

struct nop_usb_xceiv {
    struct usb_phy      phy;
    struct device       *dev;
};

static struct platform_device *pd;

void usb_nop_xceiv_register(void)
{
    if (pd)
        return;
    pd = platform_device_register_simple("nop_usb_xceiv", -1, NULL, 0);
    if (!pd) {
        printk(KERN_ERR "Unable to register usb nop transceiver\n");
        return;
    }
}
EXPORT_SYMBOL(usb_nop_xceiv_register);

void usb_nop_xceiv_unregister(void)
{
    platform_device_unregister(pd);
    pd = NULL;
}
EXPORT_SYMBOL(usb_nop_xceiv_unregister);

static int nop_set_suspend(struct usb_phy *x, int suspend)
{
    return 0;
}

static int nop_set_peripheral(struct usb_otg *otg, struct usb_gadget *gadget)
{
    if (!otg)
        return -ENODEV;

    if (!gadget) {
        otg->gadget = NULL;
        return -ENODEV;
    }

    otg->gadget = gadget;
    otg->phy->state = OTG_STATE_B_IDLE;
    return 0;
}

static int nop_set_host(struct usb_otg *otg, struct usb_bus *host)
{
    if (!otg)
        return -ENODEV;

    if (!host) {
        otg->host = NULL;
        return -ENODEV;
    }

    otg->host = host;
    return 0;
}

static int __devinit nop_usb_xceiv_probe(struct platform_device *pdev)
{
    struct nop_usb_xceiv_platform_data *pdata = pdev->dev.platform_data;
    struct nop_usb_xceiv    *nop;
    enum usb_phy_type   type = USB_PHY_TYPE_USB2;
    int err;

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

    nop->phy.otg = kzalloc(sizeof *nop->phy.otg, GFP_KERNEL);
    if (!nop->phy.otg) {
        kfree(nop);
        return -ENOMEM;
    }

    if (pdata)
        type = pdata->type;

    nop->dev        = &pdev->dev;
    nop->phy.dev        = nop->dev;
    nop->phy.label      = "nop-xceiv";
    nop->phy.set_suspend    = nop_set_suspend;
    nop->phy.state      = OTG_STATE_UNDEFINED;

    nop->phy.otg->phy       = &nop->phy;
    nop->phy.otg->set_host      = nop_set_host;
    nop->phy.otg->set_peripheral    = nop_set_peripheral;

    err = usb_add_phy(&nop->phy, type);
    if (err) {
        dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
            err);
        goto exit;
    }

    platform_set_drvdata(pdev, nop);

    ATOMIC_INIT_NOTIFIER_HEAD(&nop->phy.notifier);

    return 0;
exit:
    kfree(nop->phy.otg);
    kfree(nop);
    return err;
}

static int __devexit nop_usb_xceiv_remove(struct platform_device *pdev)
{
    struct nop_usb_xceiv *nop = platform_get_drvdata(pdev);

    usb_remove_phy(&nop->phy);

    platform_set_drvdata(pdev, NULL);
    kfree(nop->phy.otg);
    kfree(nop);

    return 0;
}

static struct platform_driver nop_usb_xceiv_driver = {
    .probe      = nop_usb_xceiv_probe,
    .remove     = __devexit_p(nop_usb_xceiv_remove),
    .driver     = {
        .name   = "nop_usb_xceiv",
        .owner  = THIS_MODULE,
    },
};

static int __init nop_usb_xceiv_init(void)
{
    return platform_driver_register(&nop_usb_xceiv_driver);
}
subsys_initcall(nop_usb_xceiv_init);

static void __exit nop_usb_xceiv_exit(void)
{
    platform_driver_unregister(&nop_usb_xceiv_driver);
}
module_exit(nop_usb_xceiv_exit);

MODULE_ALIAS("platform:nop_usb_xceiv");
MODULE_AUTHOR("Texas Instruments Inc");
MODULE_DESCRIPTION("NOP USB Transceiver driver");
MODULE_LICENSE("GPL");