/*
 * Copyright 2012 Freescale Semiconductor, Inc.
 * Copyright (C) 2012 Marek Vasut <marex@denx.de>
 * on behalf of DENX Software Engineering GmbH
 *
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/usb/otg.h>
#include <linux/stmp_device.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/workqueue.h>

#define DRIVER_NAME "mxs_phy"

#define HW_USBPHY_PWD				0x00
#define HW_USBPHY_CTRL				0x30
#define HW_USBPHY_CTRL_SET			0x34
#define HW_USBPHY_CTRL_CLR			0x38

#define BM_USBPHY_CTRL_SFTRST			BIT(31)
#define BM_USBPHY_CTRL_CLKGATE			BIT(30)
#define BM_USBPHY_CTRL_ENUTMILEVEL3		BIT(15)
#define BM_USBPHY_CTRL_ENUTMILEVEL2		BIT(14)
#define BM_USBPHY_CTRL_ENHOSTDISCONDETECT	BIT(1)

/*
 * Amount of delay in miliseconds to safely enable ENHOSTDISCONDETECT bit
 * so that connection and reset processing can be completed for the root hub.
 */
#define MXY_PHY_ENHOSTDISCONDETECT_DELAY	250

struct mxs_phy {
	struct usb_phy phy;
	struct clk *clk;
	struct delayed_work enhostdiscondetect_work;
};

#define to_mxs_phy(p) container_of((p), struct mxs_phy, phy)

static void mxs_phy_hw_init(struct mxs_phy *mxs_phy)
{
	void __iomem *base = mxs_phy->phy.io_priv;

	stmp_reset_block(base + HW_USBPHY_CTRL);

	/* Power up the PHY */
	writel_relaxed(0, base + HW_USBPHY_PWD);

	/* enable FS/LS device */
	writel_relaxed(BM_USBPHY_CTRL_ENUTMILEVEL2 |
			BM_USBPHY_CTRL_ENUTMILEVEL3,
			base + HW_USBPHY_CTRL_SET);
}

static int mxs_phy_init(struct usb_phy *phy)
{
	struct mxs_phy *mxs_phy = to_mxs_phy(phy);

	clk_prepare_enable(mxs_phy->clk);
	mxs_phy_hw_init(mxs_phy);
	INIT_DELAYED_WORK(&mxs_phy->enhostdiscondetect_work, NULL);

	return 0;
}

static void mxs_phy_shutdown(struct usb_phy *phy)
{
	struct mxs_phy *mxs_phy = to_mxs_phy(phy);

	writel_relaxed(BM_USBPHY_CTRL_CLKGATE,
			phy->io_priv + HW_USBPHY_CTRL_SET);

	clk_disable_unprepare(mxs_phy->clk);
}

static void mxs_phy_enhostdiscondetect_delay(struct work_struct *ws)
{
	struct mxs_phy *mxs_phy = container_of(ws, struct mxs_phy,
						enhostdiscondetect_work.work);

	/* Enable HOSTDISCONDETECT after delay. */
	dev_dbg(mxs_phy->phy.dev, "Setting ENHOSTDISCONDETECT\n");
	writel_relaxed(BM_USBPHY_CTRL_ENHOSTDISCONDETECT,
				mxs_phy->phy.io_priv + HW_USBPHY_CTRL_SET);
}

static int mxs_phy_on_connect(struct usb_phy *phy, int port)
{
	struct mxs_phy *mxs_phy = to_mxs_phy(phy);

	dev_dbg(phy->dev, "Connect on port %d\n", port);

	mxs_phy_hw_init(mxs_phy);

	/*
	 * Delay enabling ENHOSTDISCONDETECT so that connection and
	 * reset processing can be completed for the root hub.
	 */
	dev_dbg(phy->dev, "Delaying setting ENHOSTDISCONDETECT\n");
	PREPARE_DELAYED_WORK(&mxs_phy->enhostdiscondetect_work,
			mxs_phy_enhostdiscondetect_delay);
	schedule_delayed_work(&mxs_phy->enhostdiscondetect_work,
			msecs_to_jiffies(MXY_PHY_ENHOSTDISCONDETECT_DELAY));

	return 0;
}

static int mxs_phy_on_disconnect(struct usb_phy *phy, int port)
{
	dev_dbg(phy->dev, "Disconnect on port %d\n", port);

	/* No need to delay before clearing ENHOSTDISCONDETECT. */
	dev_dbg(phy->dev, "Clearing ENHOSTDISCONDETECT\n");
	writel_relaxed(BM_USBPHY_CTRL_ENHOSTDISCONDETECT,
			phy->io_priv + HW_USBPHY_CTRL_CLR);

	return 0;
}

static int mxs_phy_probe(struct platform_device *pdev)
{
	struct resource *res;
	void __iomem *base;
	struct clk *clk;
	struct mxs_phy *mxs_phy;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "can't get device resources\n");
		return -ENOENT;
	}

	base = devm_request_and_ioremap(&pdev->dev, res);
	if (!base)
		return -EBUSY;

	clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev,
			"can't get the clock, err=%ld", PTR_ERR(clk));
		return PTR_ERR(clk);
	}

	mxs_phy = devm_kzalloc(&pdev->dev, sizeof(*mxs_phy), GFP_KERNEL);
	if (!mxs_phy) {
		dev_err(&pdev->dev, "Failed to allocate USB PHY structure!\n");
		return -ENOMEM;
	}

	mxs_phy->phy.io_priv		= base;
	mxs_phy->phy.dev		= &pdev->dev;
	mxs_phy->phy.label		= DRIVER_NAME;
	mxs_phy->phy.init		= mxs_phy_init;
	mxs_phy->phy.shutdown		= mxs_phy_shutdown;
	mxs_phy->phy.notify_connect	= mxs_phy_on_connect;
	mxs_phy->phy.notify_disconnect	= mxs_phy_on_disconnect;

	ATOMIC_INIT_NOTIFIER_HEAD(&mxs_phy->phy.notifier);

	mxs_phy->clk = clk;

	platform_set_drvdata(pdev, &mxs_phy->phy);

	return 0;
}

static int __devexit mxs_phy_remove(struct platform_device *pdev)
{
	platform_set_drvdata(pdev, NULL);

	return 0;
}

static const struct of_device_id mxs_phy_dt_ids[] = {
	{ .compatible = "fsl,imx23-usbphy", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_phy_dt_ids);

static struct platform_driver mxs_phy_driver = {
	.probe = mxs_phy_probe,
	.remove = __devexit_p(mxs_phy_remove),
	.driver = {
		.name = DRIVER_NAME,
		.owner	= THIS_MODULE,
		.of_match_table = mxs_phy_dt_ids,
	 },
};

static int __init mxs_phy_module_init(void)
{
	return platform_driver_register(&mxs_phy_driver);
}
postcore_initcall(mxs_phy_module_init);

static void __exit mxs_phy_module_exit(void)
{
	platform_driver_unregister(&mxs_phy_driver);
}
module_exit(mxs_phy_module_exit);

MODULE_ALIAS("platform:mxs-usb-phy");
MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
MODULE_AUTHOR("Richard Zhao <richard.zhao@freescale.com>");
MODULE_DESCRIPTION("Freescale MXS USB PHY driver");
MODULE_LICENSE("GPL");