/*
 * Driver for EHCI UHP on Atmel chips
 *
 *  Copyright (C) 2009 Atmel Corporation,
 *                     Nicolas Ferre <nicolas.ferre@atmel.com>
 *
 *  Based on various ehci-*.c drivers
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive for
 * more details.
 */

#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>

#include "ehci.h"

#define DRIVER_DESC "EHCI Atmel driver"

static const char hcd_name[] = "ehci-atmel";

/* interface and function clocks */
#define hcd_to_atmel_ehci_priv(h) \
        ((struct atmel_ehci_priv *)hcd_to_ehci(h)->priv)

struct atmel_ehci_priv {
        struct clk *iclk;
        struct clk *uclk;
        bool clocked;
};

static struct hc_driver __read_mostly ehci_atmel_hc_driver;

static const struct ehci_driver_overrides ehci_atmel_drv_overrides __initconst = {
        .extra_priv_size = sizeof(struct atmel_ehci_priv),
};

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

static void atmel_start_clock(struct atmel_ehci_priv *atmel_ehci)
{
        if (atmel_ehci->clocked)
                return;

        clk_prepare_enable(atmel_ehci->uclk);
        clk_prepare_enable(atmel_ehci->iclk);
        atmel_ehci->clocked = true;
}

static void atmel_stop_clock(struct atmel_ehci_priv *atmel_ehci)
{
        if (!atmel_ehci->clocked)
                return;

        clk_disable_unprepare(atmel_ehci->iclk);
        clk_disable_unprepare(atmel_ehci->uclk);
        atmel_ehci->clocked = false;
}

static void atmel_start_ehci(struct platform_device *pdev)
{
        struct usb_hcd *hcd = platform_get_drvdata(pdev);
        struct atmel_ehci_priv *atmel_ehci = hcd_to_atmel_ehci_priv(hcd);

        dev_dbg(&pdev->dev, "start\n");
        atmel_start_clock(atmel_ehci);
}

static void atmel_stop_ehci(struct platform_device *pdev)
{
        struct usb_hcd *hcd = platform_get_drvdata(pdev);
        struct atmel_ehci_priv *atmel_ehci = hcd_to_atmel_ehci_priv(hcd);

        dev_dbg(&pdev->dev, "stop\n");
        atmel_stop_clock(atmel_ehci);
}

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

static int ehci_atmel_drv_probe(struct platform_device *pdev)
{
        struct usb_hcd *hcd;
        const struct hc_driver *driver = &ehci_atmel_hc_driver;
        struct resource *res;
        struct ehci_hcd *ehci;
        struct atmel_ehci_priv *atmel_ehci;
        int irq;
        int retval;

        if (usb_disabled())
                return -ENODEV;

        pr_debug("Initializing Atmel-SoC USB Host Controller\n");

        irq = platform_get_irq(pdev, 0);
        if (irq <= 0) {
                dev_err(&pdev->dev,
                        "Found HC with no IRQ. Check %s setup!\n",
                        dev_name(&pdev->dev));
                retval = -ENODEV;
                goto fail_create_hcd;
        }

        /* Right now device-tree probed devices don't get dma_mask set.
         * Since shared usb code relies on it, set it here for now.
         * Once we have dma capability bindings this can go away.
         */
        retval = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
        if (retval)
                goto fail_create_hcd;

        hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
        if (!hcd) {
                retval = -ENOMEM;
                goto fail_create_hcd;
        }
        atmel_ehci = hcd_to_atmel_ehci_priv(hcd);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        hcd->regs = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(hcd->regs)) {
                retval = PTR_ERR(hcd->regs);
                goto fail_request_resource;
        }

        hcd->rsrc_start = res->start;
        hcd->rsrc_len = resource_size(res);

        atmel_ehci->iclk = devm_clk_get(&pdev->dev, "ehci_clk");
        if (IS_ERR(atmel_ehci->iclk)) {
                dev_err(&pdev->dev, "Error getting interface clock\n");
                retval = -ENOENT;
                goto fail_request_resource;
        }

        atmel_ehci->uclk = devm_clk_get(&pdev->dev, "usb_clk");
        if (IS_ERR(atmel_ehci->uclk)) {
                dev_err(&pdev->dev, "failed to get uclk\n");
                retval = PTR_ERR(atmel_ehci->uclk);
                goto fail_request_resource;
        }

        ehci = hcd_to_ehci(hcd);
        /* registers start at offset 0x0 */
        ehci->caps = hcd->regs;

        atmel_start_ehci(pdev);

        retval = usb_add_hcd(hcd, irq, IRQF_SHARED);
        if (retval)
                goto fail_add_hcd;
        device_wakeup_enable(hcd->self.controller);

        return retval;

fail_add_hcd:
        atmel_stop_ehci(pdev);
fail_request_resource:
        usb_put_hcd(hcd);
fail_create_hcd:
        dev_err(&pdev->dev, "init %s fail, %d\n",
                dev_name(&pdev->dev), retval);

        return retval;
}

static int ehci_atmel_drv_remove(struct platform_device *pdev)
{
        struct usb_hcd *hcd = platform_get_drvdata(pdev);

        usb_remove_hcd(hcd);
        usb_put_hcd(hcd);

        atmel_stop_ehci(pdev);

        return 0;
}

static int __maybe_unused ehci_atmel_drv_suspend(struct device *dev)
{
        struct usb_hcd *hcd = dev_get_drvdata(dev);
        struct atmel_ehci_priv *atmel_ehci = hcd_to_atmel_ehci_priv(hcd);
        int ret;

        ret = ehci_suspend(hcd, false);
        if (ret)
                return ret;

        atmel_stop_clock(atmel_ehci);
        return 0;
}

static int __maybe_unused ehci_atmel_drv_resume(struct device *dev)
{
        struct usb_hcd *hcd = dev_get_drvdata(dev);
        struct atmel_ehci_priv *atmel_ehci = hcd_to_atmel_ehci_priv(hcd);

        atmel_start_clock(atmel_ehci);
        return ehci_resume(hcd, false);
}

#ifdef CONFIG_OF
static const struct of_device_id atmel_ehci_dt_ids[] = {
        { .compatible = "atmel,at91sam9g45-ehci" },
        { /* sentinel */ }
};

MODULE_DEVICE_TABLE(of, atmel_ehci_dt_ids);
#endif

static SIMPLE_DEV_PM_OPS(ehci_atmel_pm_ops, ehci_atmel_drv_suspend,
                                        ehci_atmel_drv_resume);

static struct platform_driver ehci_atmel_driver = {
        .probe          = ehci_atmel_drv_probe,
        .remove         = ehci_atmel_drv_remove,
        .shutdown       = usb_hcd_platform_shutdown,
        .driver         = {
                .name   = "atmel-ehci",
                .pm     = &ehci_atmel_pm_ops,
                .of_match_table = of_match_ptr(atmel_ehci_dt_ids),
        },
};

static int __init ehci_atmel_init(void)
{
        if (usb_disabled())
                return -ENODEV;

        pr_info("%s: " DRIVER_DESC "\n", hcd_name);
        ehci_init_driver(&ehci_atmel_hc_driver, &ehci_atmel_drv_overrides);
        return platform_driver_register(&ehci_atmel_driver);
}
module_init(ehci_atmel_init);

static void __exit ehci_atmel_cleanup(void)
{
        platform_driver_unregister(&ehci_atmel_driver);
}
module_exit(ehci_atmel_cleanup);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_ALIAS("platform:atmel-ehci");
MODULE_AUTHOR("Nicolas Ferre");
MODULE_LICENSE("GPL");