/*
 * Renesas R-Car USB phy driver
 *
 * Copyright (C) 2012 Renesas Solutions Corp.
 * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/delay.h>
#include <linux/io.h>
#include <linux/usb/otg.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/module.h>

/* USBH common register */
#define USBPCTRL0       0x0800
#define USBPCTRL1       0x0804
#define USBST           0x0808
#define USBEH0          0x080C
#define USBOH0          0x081C
#define USBCTL0         0x0858
#define EIIBC1          0x0094
#define EIIBC2          0x009C

/* USBPCTRL1 */
#define PHY_RST         (1 << 2)
#define PLL_ENB         (1 << 1)
#define PHY_ENB         (1 << 0)

/* USBST */
#define ST_ACT          (1 << 31)
#define ST_PLL          (1 << 30)

struct rcar_usb_phy_priv {
        struct usb_phy phy;
        spinlock_t lock;

        void __iomem *reg0;
        void __iomem *reg1;
        int counter;
};

#define usb_phy_to_priv(p) container_of(p, struct rcar_usb_phy_priv, phy)


/*
 * USB initial/install operation.
 *
 * This function setup USB phy.
 * The used value and setting order came from
 * [USB :: Initial setting] on datasheet.
 */
static int rcar_usb_phy_init(struct usb_phy *phy)
{
        struct rcar_usb_phy_priv *priv = usb_phy_to_priv(phy);
        struct device *dev = phy->dev;
        void __iomem *reg0 = priv->reg0;
        void __iomem *reg1 = priv->reg1;
        int i;
        u32 val;
        unsigned long flags;

        spin_lock_irqsave(&priv->lock, flags);
        if (priv->counter++ == 0) {

                /*
                 * USB phy start-up
                 */

                /* (1) USB-PHY standby release */
                iowrite32(PHY_ENB, (reg0 + USBPCTRL1));

                /* (2) start USB-PHY internal PLL */
                iowrite32(PHY_ENB | PLL_ENB, (reg0 + USBPCTRL1));

                /* (3) USB module status check */
                for (i = 0; i < 1024; i++) {
                        udelay(10);
                        val = ioread32(reg0 + USBST);
                        if (val == (ST_ACT | ST_PLL))
                                break;
                }

                if (val != (ST_ACT | ST_PLL)) {
                        dev_err(dev, "USB phy not ready\n");
                        goto phy_init_end;
                }

                /* (4) USB-PHY reset clear */
                iowrite32(PHY_ENB | PLL_ENB | PHY_RST, (reg0 + USBPCTRL1));

                /* set platform specific port settings */
                iowrite32(0x00000000, (reg0 + USBPCTRL0));

                /*
                 * EHCI IP internal buffer setting
                 * EHCI IP internal buffer enable
                 *
                 * These are recommended value of a datasheet
                 * see [USB :: EHCI internal buffer setting]
                 */
                iowrite32(0x00ff0040, (reg0 + EIIBC1));
                iowrite32(0x00ff0040, (reg1 + EIIBC1));

                iowrite32(0x00000001, (reg0 + EIIBC2));
                iowrite32(0x00000001, (reg1 + EIIBC2));

                /*
                 * Bus alignment settings
                 */

                /* (1) EHCI bus alignment (little endian) */
                iowrite32(0x00000000, (reg0 + USBEH0));

                /* (1) OHCI bus alignment (little endian) */
                iowrite32(0x00000000, (reg0 + USBOH0));
        }

phy_init_end:
        spin_unlock_irqrestore(&priv->lock, flags);

        return 0;
}

static void rcar_usb_phy_shutdown(struct usb_phy *phy)
{
        struct rcar_usb_phy_priv *priv = usb_phy_to_priv(phy);
        void __iomem *reg0 = priv->reg0;
        unsigned long flags;

        spin_lock_irqsave(&priv->lock, flags);

        if (priv->counter-- == 1) { /* last user */
                iowrite32(0x00000000, (reg0 + USBPCTRL0));
                iowrite32(0x00000000, (reg0 + USBPCTRL1));
        }

        spin_unlock_irqrestore(&priv->lock, flags);
}

static int rcar_usb_phy_probe(struct platform_device *pdev)
{
        struct rcar_usb_phy_priv *priv;
        struct resource *res0, *res1;
        struct device *dev = &pdev->dev;
        void __iomem *reg0, *reg1;
        int ret;

        res0 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        res1 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        if (!res0 || !res1) {
                dev_err(dev, "Not enough platform resources\n");
                return -EINVAL;
        }

        /*
         * CAUTION
         *
         * Because this phy address is also mapped under OHCI/EHCI address area,
         * this driver can't use devm_request_and_ioremap(dev, res) here
         */
        reg0 = devm_ioremap_nocache(dev, res0->start, resource_size(res0));
        reg1 = devm_ioremap_nocache(dev, res1->start, resource_size(res1));
        if (!reg0 || !reg1) {
                dev_err(dev, "ioremap error\n");
                return -ENOMEM;
        }

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv) {
                dev_err(dev, "priv data allocation error\n");
                return -ENOMEM;
        }

        priv->reg0              = reg0;
        priv->reg1              = reg1;
        priv->counter           = 0;
        priv->phy.dev           = dev;
        priv->phy.label         = dev_name(dev);
        priv->phy.init          = rcar_usb_phy_init;
        priv->phy.shutdown      = rcar_usb_phy_shutdown;
        spin_lock_init(&priv->lock);

        ret = usb_add_phy(&priv->phy, USB_PHY_TYPE_USB2);
        if (ret < 0) {
                dev_err(dev, "usb phy addition error\n");
                return ret;
        }

        platform_set_drvdata(pdev, priv);

        return ret;
}

static int rcar_usb_phy_remove(struct platform_device *pdev)
{
        struct rcar_usb_phy_priv *priv = platform_get_drvdata(pdev);

        usb_remove_phy(&priv->phy);

        return 0;
}

static struct platform_driver rcar_usb_phy_driver = {
        .driver         = {
                .name   = "rcar_usb_phy",
        },
        .probe          = rcar_usb_phy_probe,
        .remove         = rcar_usb_phy_remove,
};

module_platform_driver(rcar_usb_phy_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Renesas R-Car USB phy");
MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");