/*
 * Copyright 2012-2014 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/of_device.h>
#include <linux/regmap.h>
#include <linux/mfd/syscon.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 HW_USBPHY_DEBUG_SET                     0x54
#define HW_USBPHY_DEBUG_CLR                     0x58

#define HW_USBPHY_IP                            0x90
#define HW_USBPHY_IP_SET                        0x94
#define HW_USBPHY_IP_CLR                        0x98

#define BM_USBPHY_CTRL_SFTRST                   BIT(31)
#define BM_USBPHY_CTRL_CLKGATE                  BIT(30)
#define BM_USBPHY_CTRL_OTG_ID_VALUE             BIT(27)
#define BM_USBPHY_CTRL_ENAUTOSET_USBCLKS        BIT(26)
#define BM_USBPHY_CTRL_ENAUTOCLR_USBCLKGATE     BIT(25)
#define BM_USBPHY_CTRL_ENVBUSCHG_WKUP           BIT(23)
#define BM_USBPHY_CTRL_ENIDCHG_WKUP             BIT(22)
#define BM_USBPHY_CTRL_ENDPDMCHG_WKUP           BIT(21)
#define BM_USBPHY_CTRL_ENAUTOCLR_PHY_PWD        BIT(20)
#define BM_USBPHY_CTRL_ENAUTOCLR_CLKGATE        BIT(19)
#define BM_USBPHY_CTRL_ENAUTO_PWRON_PLL         BIT(18)
#define BM_USBPHY_CTRL_ENUTMILEVEL3             BIT(15)
#define BM_USBPHY_CTRL_ENUTMILEVEL2             BIT(14)
#define BM_USBPHY_CTRL_ENHOSTDISCONDETECT       BIT(1)

#define BM_USBPHY_IP_FIX                       (BIT(17) | BIT(18))

#define BM_USBPHY_DEBUG_CLKGATE                 BIT(30)

/* Anatop Registers */
#define ANADIG_ANA_MISC0                        0x150
#define ANADIG_ANA_MISC0_SET                    0x154
#define ANADIG_ANA_MISC0_CLR                    0x158

#define ANADIG_USB1_VBUS_DET_STAT               0x1c0
#define ANADIG_USB2_VBUS_DET_STAT               0x220

#define ANADIG_USB1_LOOPBACK_SET                0x1e4
#define ANADIG_USB1_LOOPBACK_CLR                0x1e8
#define ANADIG_USB2_LOOPBACK_SET                0x244
#define ANADIG_USB2_LOOPBACK_CLR                0x248

#define ANADIG_USB1_MISC                        0x1f0
#define ANADIG_USB2_MISC                        0x250

#define BM_ANADIG_ANA_MISC0_STOP_MODE_CONFIG    BIT(12)
#define BM_ANADIG_ANA_MISC0_STOP_MODE_CONFIG_SL BIT(11)

#define BM_ANADIG_USB1_VBUS_DET_STAT_VBUS_VALID BIT(3)
#define BM_ANADIG_USB2_VBUS_DET_STAT_VBUS_VALID BIT(3)

#define BM_ANADIG_USB1_LOOPBACK_UTMI_DIG_TST1   BIT(2)
#define BM_ANADIG_USB1_LOOPBACK_TSTI_TX_EN      BIT(5)
#define BM_ANADIG_USB2_LOOPBACK_UTMI_DIG_TST1   BIT(2)
#define BM_ANADIG_USB2_LOOPBACK_TSTI_TX_EN      BIT(5)

#define BM_ANADIG_USB1_MISC_RX_VPIN_FS          BIT(29)
#define BM_ANADIG_USB1_MISC_RX_VMIN_FS          BIT(28)
#define BM_ANADIG_USB2_MISC_RX_VPIN_FS          BIT(29)
#define BM_ANADIG_USB2_MISC_RX_VMIN_FS          BIT(28)

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

/* Do disconnection between PHY and controller without vbus */
#define MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS    BIT(0)

/*
 * The PHY will be in messy if there is a wakeup after putting
 * bus to suspend (set portsc.suspendM) but before setting PHY to low
 * power mode (set portsc.phcd).
 */
#define MXS_PHY_ABNORMAL_IN_SUSPEND             BIT(1)

/*
 * The SOF sends too fast after resuming, it will cause disconnection
 * between host and high speed device.
 */
#define MXS_PHY_SENDING_SOF_TOO_FAST            BIT(2)

/*
 * IC has bug fixes logic, they include
 * MXS_PHY_ABNORMAL_IN_SUSPEND and MXS_PHY_SENDING_SOF_TOO_FAST
 * which are described at above flags, the RTL will handle it
 * according to different versions.
 */
#define MXS_PHY_NEED_IP_FIX                     BIT(3)

struct mxs_phy_data {
        unsigned int flags;
};

static const struct mxs_phy_data imx23_phy_data = {
        .flags = MXS_PHY_ABNORMAL_IN_SUSPEND | MXS_PHY_SENDING_SOF_TOO_FAST,
};

static const struct mxs_phy_data imx6q_phy_data = {
        .flags = MXS_PHY_SENDING_SOF_TOO_FAST |
                MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS |
                MXS_PHY_NEED_IP_FIX,
};

static const struct mxs_phy_data imx6sl_phy_data = {
        .flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS |
                MXS_PHY_NEED_IP_FIX,
};

static const struct mxs_phy_data vf610_phy_data = {
        .flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS |
                MXS_PHY_NEED_IP_FIX,
};

static const struct mxs_phy_data imx6sx_phy_data = {
        .flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS,
};

static const struct mxs_phy_data imx6ul_phy_data = {
        .flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS,
};

static const struct of_device_id mxs_phy_dt_ids[] = {
        { .compatible = "fsl,imx6sx-usbphy", .data = &imx6sx_phy_data, },
        { .compatible = "fsl,imx6sl-usbphy", .data = &imx6sl_phy_data, },
        { .compatible = "fsl,imx6q-usbphy", .data = &imx6q_phy_data, },
        { .compatible = "fsl,imx23-usbphy", .data = &imx23_phy_data, },
        { .compatible = "fsl,vf610-usbphy", .data = &vf610_phy_data, },
        { .compatible = "fsl,imx6ul-usbphy", .data = &imx6ul_phy_data, },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_phy_dt_ids);

struct mxs_phy {
        struct usb_phy phy;
        struct clk *clk;
        const struct mxs_phy_data *data;
        struct regmap *regmap_anatop;
        int port_id;
};

static inline bool is_imx6q_phy(struct mxs_phy *mxs_phy)
{
        return mxs_phy->data == &imx6q_phy_data;
}

static inline bool is_imx6sl_phy(struct mxs_phy *mxs_phy)
{
        return mxs_phy->data == &imx6sl_phy_data;
}

/*
 * PHY needs some 32K cycles to switch from 32K clock to
 * bus (such as AHB/AXI, etc) clock.
 */
static void mxs_phy_clock_switch_delay(void)
{
        usleep_range(300, 400);
}

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

        ret = stmp_reset_block(base + HW_USBPHY_CTRL);
        if (ret)
                return ret;

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

        /*
         * USB PHY Ctrl Setting
         * - Auto clock/power on
         * - Enable full/low speed support
         */
        writel(BM_USBPHY_CTRL_ENAUTOSET_USBCLKS |
                BM_USBPHY_CTRL_ENAUTOCLR_USBCLKGATE |
                BM_USBPHY_CTRL_ENAUTOCLR_PHY_PWD |
                BM_USBPHY_CTRL_ENAUTOCLR_CLKGATE |
                BM_USBPHY_CTRL_ENAUTO_PWRON_PLL |
                BM_USBPHY_CTRL_ENUTMILEVEL2 |
                BM_USBPHY_CTRL_ENUTMILEVEL3,
               base + HW_USBPHY_CTRL_SET);

        if (mxs_phy->data->flags & MXS_PHY_NEED_IP_FIX)
                writel(BM_USBPHY_IP_FIX, base + HW_USBPHY_IP_SET);

        return 0;
}

/* Return true if the vbus is there */
static bool mxs_phy_get_vbus_status(struct mxs_phy *mxs_phy)
{
        unsigned int vbus_value = 0;

        if (!mxs_phy->regmap_anatop)
                return false;

        if (mxs_phy->port_id == 0)
                regmap_read(mxs_phy->regmap_anatop,
                        ANADIG_USB1_VBUS_DET_STAT,
                        &vbus_value);
        else if (mxs_phy->port_id == 1)
                regmap_read(mxs_phy->regmap_anatop,
                        ANADIG_USB2_VBUS_DET_STAT,
                        &vbus_value);

        if (vbus_value & BM_ANADIG_USB1_VBUS_DET_STAT_VBUS_VALID)
                return true;
        else
                return false;
}

static void __mxs_phy_disconnect_line(struct mxs_phy *mxs_phy, bool disconnect)
{
        void __iomem *base = mxs_phy->phy.io_priv;
        u32 reg;

        if (disconnect)
                writel_relaxed(BM_USBPHY_DEBUG_CLKGATE,
                        base + HW_USBPHY_DEBUG_CLR);

        if (mxs_phy->port_id == 0) {
                reg = disconnect ? ANADIG_USB1_LOOPBACK_SET
                        : ANADIG_USB1_LOOPBACK_CLR;
                regmap_write(mxs_phy->regmap_anatop, reg,
                        BM_ANADIG_USB1_LOOPBACK_UTMI_DIG_TST1 |
                        BM_ANADIG_USB1_LOOPBACK_TSTI_TX_EN);
        } else if (mxs_phy->port_id == 1) {
                reg = disconnect ? ANADIG_USB2_LOOPBACK_SET
                        : ANADIG_USB2_LOOPBACK_CLR;
                regmap_write(mxs_phy->regmap_anatop, reg,
                        BM_ANADIG_USB2_LOOPBACK_UTMI_DIG_TST1 |
                        BM_ANADIG_USB2_LOOPBACK_TSTI_TX_EN);
        }

        if (!disconnect)
                writel_relaxed(BM_USBPHY_DEBUG_CLKGATE,
                        base + HW_USBPHY_DEBUG_SET);

        /* Delay some time, and let Linestate be SE0 for controller */
        if (disconnect)
                usleep_range(500, 1000);
}

static bool mxs_phy_is_otg_host(struct mxs_phy *mxs_phy)
{
        void __iomem *base = mxs_phy->phy.io_priv;
        u32 phyctrl = readl(base + HW_USBPHY_CTRL);

        if (IS_ENABLED(CONFIG_USB_OTG) &&
                        !(phyctrl & BM_USBPHY_CTRL_OTG_ID_VALUE))
                return true;

        return false;
}

static void mxs_phy_disconnect_line(struct mxs_phy *mxs_phy, bool on)
{
        bool vbus_is_on = false;

        /* If the SoCs don't need to disconnect line without vbus, quit */
        if (!(mxs_phy->data->flags & MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS))
                return;

        /* If the SoCs don't have anatop, quit */
        if (!mxs_phy->regmap_anatop)
                return;

        vbus_is_on = mxs_phy_get_vbus_status(mxs_phy);

        if (on && !vbus_is_on && !mxs_phy_is_otg_host(mxs_phy))
                __mxs_phy_disconnect_line(mxs_phy, true);
        else
                __mxs_phy_disconnect_line(mxs_phy, false);

}

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

        mxs_phy_clock_switch_delay();
        ret = clk_prepare_enable(mxs_phy->clk);
        if (ret)
                return ret;

        return mxs_phy_hw_init(mxs_phy);
}

static void mxs_phy_shutdown(struct usb_phy *phy)
{
        struct mxs_phy *mxs_phy = to_mxs_phy(phy);
        u32 value = BM_USBPHY_CTRL_ENVBUSCHG_WKUP |
                        BM_USBPHY_CTRL_ENDPDMCHG_WKUP |
                        BM_USBPHY_CTRL_ENIDCHG_WKUP |
                        BM_USBPHY_CTRL_ENAUTOSET_USBCLKS |
                        BM_USBPHY_CTRL_ENAUTOCLR_USBCLKGATE |
                        BM_USBPHY_CTRL_ENAUTOCLR_PHY_PWD |
                        BM_USBPHY_CTRL_ENAUTOCLR_CLKGATE |
                        BM_USBPHY_CTRL_ENAUTO_PWRON_PLL;

        writel(value, phy->io_priv + HW_USBPHY_CTRL_CLR);
        writel(0xffffffff, phy->io_priv + HW_USBPHY_PWD);

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

        clk_disable_unprepare(mxs_phy->clk);
}

static bool mxs_phy_is_low_speed_connection(struct mxs_phy *mxs_phy)
{
        unsigned int line_state;
        /* bit definition is the same for all controllers */
        unsigned int dp_bit = BM_ANADIG_USB1_MISC_RX_VPIN_FS,
                     dm_bit = BM_ANADIG_USB1_MISC_RX_VMIN_FS;
        unsigned int reg = ANADIG_USB1_MISC;

        /* If the SoCs don't have anatop, quit */
        if (!mxs_phy->regmap_anatop)
                return false;

        if (mxs_phy->port_id == 0)
                reg = ANADIG_USB1_MISC;
        else if (mxs_phy->port_id == 1)
                reg = ANADIG_USB2_MISC;

        regmap_read(mxs_phy->regmap_anatop, reg, &line_state);

        if ((line_state & (dp_bit | dm_bit)) ==  dm_bit)
                return true;
        else
                return false;
}

static int mxs_phy_suspend(struct usb_phy *x, int suspend)
{
        int ret;
        struct mxs_phy *mxs_phy = to_mxs_phy(x);
        bool low_speed_connection, vbus_is_on;

        low_speed_connection = mxs_phy_is_low_speed_connection(mxs_phy);
        vbus_is_on = mxs_phy_get_vbus_status(mxs_phy);

        if (suspend) {
                /*
                 * FIXME: Do not power down RXPWD1PT1 bit for low speed
                 * connect. The low speed connection will have problem at
                 * very rare cases during usb suspend and resume process.
                 */
                if (low_speed_connection & vbus_is_on) {
                        /*
                         * If value to be set as pwd value is not 0xffffffff,
                         * several 32Khz cycles are needed.
                         */
                        mxs_phy_clock_switch_delay();
                        writel(0xffbfffff, x->io_priv + HW_USBPHY_PWD);
                } else {
                        writel(0xffffffff, x->io_priv + HW_USBPHY_PWD);
                }
                writel(BM_USBPHY_CTRL_CLKGATE,
                       x->io_priv + HW_USBPHY_CTRL_SET);
                clk_disable_unprepare(mxs_phy->clk);
        } else {
                mxs_phy_clock_switch_delay();
                ret = clk_prepare_enable(mxs_phy->clk);
                if (ret)
                        return ret;
                writel(BM_USBPHY_CTRL_CLKGATE,
                       x->io_priv + HW_USBPHY_CTRL_CLR);
                writel(0, x->io_priv + HW_USBPHY_PWD);
        }

        return 0;
}

static int mxs_phy_set_wakeup(struct usb_phy *x, bool enabled)
{
        struct mxs_phy *mxs_phy = to_mxs_phy(x);
        u32 value = BM_USBPHY_CTRL_ENVBUSCHG_WKUP |
                        BM_USBPHY_CTRL_ENDPDMCHG_WKUP |
                                BM_USBPHY_CTRL_ENIDCHG_WKUP;
        if (enabled) {
                mxs_phy_disconnect_line(mxs_phy, true);
                writel_relaxed(value, x->io_priv + HW_USBPHY_CTRL_SET);
        } else {
                writel_relaxed(value, x->io_priv + HW_USBPHY_CTRL_CLR);
                mxs_phy_disconnect_line(mxs_phy, false);
        }

        return 0;
}

static int mxs_phy_on_connect(struct usb_phy *phy,
                enum usb_device_speed speed)
{
        dev_dbg(phy->dev, "%s device has connected\n",
                (speed == USB_SPEED_HIGH) ? "HS" : "FS/LS");

        if (speed == USB_SPEED_HIGH)
                writel(BM_USBPHY_CTRL_ENHOSTDISCONDETECT,
                       phy->io_priv + HW_USBPHY_CTRL_SET);

        return 0;
}

static int mxs_phy_on_disconnect(struct usb_phy *phy,
                enum usb_device_speed speed)
{
        dev_dbg(phy->dev, "%s device has disconnected\n",
                (speed == USB_SPEED_HIGH) ? "HS" : "FS/LS");

        /* Sometimes, the speed is not high speed when the error occurs */
        if (readl(phy->io_priv + HW_USBPHY_CTRL) &
                        BM_USBPHY_CTRL_ENHOSTDISCONDETECT)
                writel(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;
        int ret;
        const struct of_device_id *of_id;
        struct device_node *np = pdev->dev.of_node;

        of_id = of_match_device(mxs_phy_dt_ids, &pdev->dev);
        if (!of_id)
                return -ENODEV;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(base))
                return PTR_ERR(base);

        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)
                return -ENOMEM;

        /* Some SoCs don't have anatop registers */
        if (of_get_property(np, "fsl,anatop", NULL)) {
                mxs_phy->regmap_anatop = syscon_regmap_lookup_by_phandle
                        (np, "fsl,anatop");
                if (IS_ERR(mxs_phy->regmap_anatop)) {
                        dev_dbg(&pdev->dev,
                                "failed to find regmap for anatop\n");
                        return PTR_ERR(mxs_phy->regmap_anatop);
                }
        }

        ret = of_alias_get_id(np, "usbphy");
        if (ret < 0)
                dev_dbg(&pdev->dev, "failed to get alias id, errno %d\n", ret);
        mxs_phy->port_id = ret;

        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.set_suspend        = mxs_phy_suspend;
        mxs_phy->phy.notify_connect     = mxs_phy_on_connect;
        mxs_phy->phy.notify_disconnect  = mxs_phy_on_disconnect;
        mxs_phy->phy.type               = USB_PHY_TYPE_USB2;
        mxs_phy->phy.set_wakeup         = mxs_phy_set_wakeup;

        mxs_phy->clk = clk;
        mxs_phy->data = of_id->data;

        platform_set_drvdata(pdev, mxs_phy);

        device_set_wakeup_capable(&pdev->dev, true);

        return usb_add_phy_dev(&mxs_phy->phy);
}

static int mxs_phy_remove(struct platform_device *pdev)
{
        struct mxs_phy *mxs_phy = platform_get_drvdata(pdev);

        usb_remove_phy(&mxs_phy->phy);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static void mxs_phy_enable_ldo_in_suspend(struct mxs_phy *mxs_phy, bool on)
{
        unsigned int reg = on ? ANADIG_ANA_MISC0_SET : ANADIG_ANA_MISC0_CLR;

        /* If the SoCs don't have anatop, quit */
        if (!mxs_phy->regmap_anatop)
                return;

        if (is_imx6q_phy(mxs_phy))
                regmap_write(mxs_phy->regmap_anatop, reg,
                        BM_ANADIG_ANA_MISC0_STOP_MODE_CONFIG);
        else if (is_imx6sl_phy(mxs_phy))
                regmap_write(mxs_phy->regmap_anatop,
                        reg, BM_ANADIG_ANA_MISC0_STOP_MODE_CONFIG_SL);
}

static int mxs_phy_system_suspend(struct device *dev)
{
        struct mxs_phy *mxs_phy = dev_get_drvdata(dev);

        if (device_may_wakeup(dev))
                mxs_phy_enable_ldo_in_suspend(mxs_phy, true);

        return 0;
}

static int mxs_phy_system_resume(struct device *dev)
{
        struct mxs_phy *mxs_phy = dev_get_drvdata(dev);

        if (device_may_wakeup(dev))
                mxs_phy_enable_ldo_in_suspend(mxs_phy, false);

        return 0;
}
#endif /* CONFIG_PM_SLEEP */

static SIMPLE_DEV_PM_OPS(mxs_phy_pm, mxs_phy_system_suspend,
                mxs_phy_system_resume);

static struct platform_driver mxs_phy_driver = {
        .probe = mxs_phy_probe,
        .remove = mxs_phy_remove,
        .driver = {
                .name = DRIVER_NAME,
                .of_match_table = mxs_phy_dt_ids,
                .pm = &mxs_phy_pm,
         },
};

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");