/*
 * drivers/usb/otg/ab8500_usb.c
 *
 * USB transceiver driver for AB8500 chip
 *
 * Copyright (C) 2010 ST-Ericsson AB
 * Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
 *
 * 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.
 *
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/usb/otg.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/mfd/abx500.h>
#include <linux/mfd/abx500/ab8500.h>

#define AB8500_MAIN_WD_CTRL_REG 0x01
#define AB8500_USB_LINE_STAT_REG 0x80
#define AB8500_USB_PHY_CTRL_REG 0x8A

#define AB8500_BIT_OTG_STAT_ID (1 << 0)
#define AB8500_BIT_PHY_CTRL_HOST_EN (1 << 0)
#define AB8500_BIT_PHY_CTRL_DEVICE_EN (1 << 1)
#define AB8500_BIT_WD_CTRL_ENABLE (1 << 0)
#define AB8500_BIT_WD_CTRL_KICK (1 << 1)

#define AB8500_V1x_LINK_STAT_WAIT (HZ/10)
#define AB8500_WD_KICK_DELAY_US 100 /* usec */
#define AB8500_WD_V11_DISABLE_DELAY_US 100 /* usec */
#define AB8500_WD_V10_DISABLE_DELAY_MS 100 /* ms */

/* Usb line status register */
enum ab8500_usb_link_status {
        USB_LINK_NOT_CONFIGURED = 0,
        USB_LINK_STD_HOST_NC,
        USB_LINK_STD_HOST_C_NS,
        USB_LINK_STD_HOST_C_S,
        USB_LINK_HOST_CHG_NM,
        USB_LINK_HOST_CHG_HS,
        USB_LINK_HOST_CHG_HS_CHIRP,
        USB_LINK_DEDICATED_CHG,
        USB_LINK_ACA_RID_A,
        USB_LINK_ACA_RID_B,
        USB_LINK_ACA_RID_C_NM,
        USB_LINK_ACA_RID_C_HS,
        USB_LINK_ACA_RID_C_HS_CHIRP,
        USB_LINK_HM_IDGND,
        USB_LINK_RESERVED,
        USB_LINK_NOT_VALID_LINK
};

struct ab8500_usb {
        struct usb_phy phy;
        struct device *dev;
        int irq_num_id_rise;
        int irq_num_id_fall;
        int irq_num_vbus_rise;
        int irq_num_vbus_fall;
        int irq_num_link_status;
        unsigned vbus_draw;
        struct delayed_work dwork;
        struct work_struct phy_dis_work;
        unsigned long link_status_wait;
        int rev;
};

static inline struct ab8500_usb *phy_to_ab(struct usb_phy *x)
{
        return container_of(x, struct ab8500_usb, phy);
}

static void ab8500_usb_wd_workaround(struct ab8500_usb *ab)
{
        abx500_set_register_interruptible(ab->dev,
                AB8500_SYS_CTRL2_BLOCK,
                AB8500_MAIN_WD_CTRL_REG,
                AB8500_BIT_WD_CTRL_ENABLE);

        udelay(AB8500_WD_KICK_DELAY_US);

        abx500_set_register_interruptible(ab->dev,
                AB8500_SYS_CTRL2_BLOCK,
                AB8500_MAIN_WD_CTRL_REG,
                (AB8500_BIT_WD_CTRL_ENABLE
                | AB8500_BIT_WD_CTRL_KICK));

        if (ab->rev > 0x10) /* v1.1 v2.0 */
                udelay(AB8500_WD_V11_DISABLE_DELAY_US);
        else /* v1.0 */
                msleep(AB8500_WD_V10_DISABLE_DELAY_MS);

        abx500_set_register_interruptible(ab->dev,
                AB8500_SYS_CTRL2_BLOCK,
                AB8500_MAIN_WD_CTRL_REG,
                0);
}

static void ab8500_usb_phy_ctrl(struct ab8500_usb *ab, bool sel_host,
                                        bool enable)
{
        u8 ctrl_reg;
        abx500_get_register_interruptible(ab->dev,
                                AB8500_USB,
                                AB8500_USB_PHY_CTRL_REG,
                                &ctrl_reg);
        if (sel_host) {
                if (enable)
                        ctrl_reg |= AB8500_BIT_PHY_CTRL_HOST_EN;
                else
                        ctrl_reg &= ~AB8500_BIT_PHY_CTRL_HOST_EN;
        } else {
                if (enable)
                        ctrl_reg |= AB8500_BIT_PHY_CTRL_DEVICE_EN;
                else
                        ctrl_reg &= ~AB8500_BIT_PHY_CTRL_DEVICE_EN;
        }

        abx500_set_register_interruptible(ab->dev,
                                AB8500_USB,
                                AB8500_USB_PHY_CTRL_REG,
                                ctrl_reg);

        /* Needed to enable the phy.*/
        if (enable)
                ab8500_usb_wd_workaround(ab);
}

#define ab8500_usb_host_phy_en(ab)      ab8500_usb_phy_ctrl(ab, true, true)
#define ab8500_usb_host_phy_dis(ab)     ab8500_usb_phy_ctrl(ab, true, false)
#define ab8500_usb_peri_phy_en(ab)      ab8500_usb_phy_ctrl(ab, false, true)
#define ab8500_usb_peri_phy_dis(ab)     ab8500_usb_phy_ctrl(ab, false, false)

static int ab8500_usb_link_status_update(struct ab8500_usb *ab)
{
        u8 reg;
        enum ab8500_usb_link_status lsts;
        void *v = NULL;
        enum usb_phy_events event;

        abx500_get_register_interruptible(ab->dev,
                        AB8500_USB,
                        AB8500_USB_LINE_STAT_REG,
                        &reg);

        lsts = (reg >> 3) & 0x0F;

        switch (lsts) {
        case USB_LINK_NOT_CONFIGURED:
        case USB_LINK_RESERVED:
        case USB_LINK_NOT_VALID_LINK:
                /* TODO: Disable regulators. */
                ab8500_usb_host_phy_dis(ab);
                ab8500_usb_peri_phy_dis(ab);
                ab->phy.state = OTG_STATE_B_IDLE;
                ab->phy.otg->default_a = false;
                ab->vbus_draw = 0;
                event = USB_EVENT_NONE;
                break;

        case USB_LINK_STD_HOST_NC:
        case USB_LINK_STD_HOST_C_NS:
        case USB_LINK_STD_HOST_C_S:
        case USB_LINK_HOST_CHG_NM:
        case USB_LINK_HOST_CHG_HS:
        case USB_LINK_HOST_CHG_HS_CHIRP:
                if (ab->phy.otg->gadget) {
                        /* TODO: Enable regulators. */
                        ab8500_usb_peri_phy_en(ab);
                        v = ab->phy.otg->gadget;
                }
                event = USB_EVENT_VBUS;
                break;

        case USB_LINK_HM_IDGND:
                if (ab->phy.otg->host) {
                        /* TODO: Enable regulators. */
                        ab8500_usb_host_phy_en(ab);
                        v = ab->phy.otg->host;
                }
                ab->phy.state = OTG_STATE_A_IDLE;
                ab->phy.otg->default_a = true;
                event = USB_EVENT_ID;
                break;

        case USB_LINK_ACA_RID_A:
        case USB_LINK_ACA_RID_B:
                /* TODO */
        case USB_LINK_ACA_RID_C_NM:
        case USB_LINK_ACA_RID_C_HS:
        case USB_LINK_ACA_RID_C_HS_CHIRP:
        case USB_LINK_DEDICATED_CHG:
                /* TODO: vbus_draw */
                event = USB_EVENT_CHARGER;
                break;
        }

        atomic_notifier_call_chain(&ab->phy.notifier, event, v);

        return 0;
}

static void ab8500_usb_delayed_work(struct work_struct *work)
{
        struct ab8500_usb *ab = container_of(work, struct ab8500_usb,
                                                dwork.work);

        ab8500_usb_link_status_update(ab);
}

static irqreturn_t ab8500_usb_v1x_common_irq(int irq, void *data)
{
        struct ab8500_usb *ab = (struct ab8500_usb *) data;

        /* Wait for link status to become stable. */
        schedule_delayed_work(&ab->dwork, ab->link_status_wait);

        return IRQ_HANDLED;
}

static irqreturn_t ab8500_usb_v1x_vbus_fall_irq(int irq, void *data)
{
        struct ab8500_usb *ab = (struct ab8500_usb *) data;

        /* Link status will not be updated till phy is disabled. */
        ab8500_usb_peri_phy_dis(ab);

        /* Wait for link status to become stable. */
        schedule_delayed_work(&ab->dwork, ab->link_status_wait);

        return IRQ_HANDLED;
}

static irqreturn_t ab8500_usb_v20_irq(int irq, void *data)
{
        struct ab8500_usb *ab = (struct ab8500_usb *) data;

        ab8500_usb_link_status_update(ab);

        return IRQ_HANDLED;
}

static void ab8500_usb_phy_disable_work(struct work_struct *work)
{
        struct ab8500_usb *ab = container_of(work, struct ab8500_usb,
                                                phy_dis_work);

        if (!ab->phy.otg->host)
                ab8500_usb_host_phy_dis(ab);

        if (!ab->phy.otg->gadget)
                ab8500_usb_peri_phy_dis(ab);
}

static int ab8500_usb_set_power(struct usb_phy *phy, unsigned mA)
{
        struct ab8500_usb *ab;

        if (!phy)
                return -ENODEV;

        ab = phy_to_ab(phy);

        ab->vbus_draw = mA;

        if (mA)
                atomic_notifier_call_chain(&ab->phy.notifier,
                                USB_EVENT_ENUMERATED, ab->phy.otg->gadget);
        return 0;
}

/* TODO: Implement some way for charging or other drivers to read
 * ab->vbus_draw.
 */

static int ab8500_usb_set_suspend(struct usb_phy *x, int suspend)
{
        /* TODO */
        return 0;
}

static int ab8500_usb_set_peripheral(struct usb_otg *otg,
                                        struct usb_gadget *gadget)
{
        struct ab8500_usb *ab;

        if (!otg)
                return -ENODEV;

        ab = phy_to_ab(otg->phy);

        /* Some drivers call this function in atomic context.
         * Do not update ab8500 registers directly till this
         * is fixed.
         */

        if (!gadget) {
                /* TODO: Disable regulators. */
                otg->gadget = NULL;
                schedule_work(&ab->phy_dis_work);
        } else {
                otg->gadget = gadget;
                otg->phy->state = OTG_STATE_B_IDLE;

                /* Phy will not be enabled if cable is already
                 * plugged-in. Schedule to enable phy.
                 * Use same delay to avoid any race condition.
                 */
                schedule_delayed_work(&ab->dwork, ab->link_status_wait);
        }

        return 0;
}

static int ab8500_usb_set_host(struct usb_otg *otg, struct usb_bus *host)
{
        struct ab8500_usb *ab;

        if (!otg)
                return -ENODEV;

        ab = phy_to_ab(otg->phy);

        /* Some drivers call this function in atomic context.
         * Do not update ab8500 registers directly till this
         * is fixed.
         */

        if (!host) {
                /* TODO: Disable regulators. */
                otg->host = NULL;
                schedule_work(&ab->phy_dis_work);
        } else {
                otg->host = host;
                /* Phy will not be enabled if cable is already
                 * plugged-in. Schedule to enable phy.
                 * Use same delay to avoid any race condition.
                 */
                schedule_delayed_work(&ab->dwork, ab->link_status_wait);
        }

        return 0;
}

static void ab8500_usb_irq_free(struct ab8500_usb *ab)
{
        if (ab->rev < 0x20) {
                free_irq(ab->irq_num_id_rise, ab);
                free_irq(ab->irq_num_id_fall, ab);
                free_irq(ab->irq_num_vbus_rise, ab);
                free_irq(ab->irq_num_vbus_fall, ab);
        } else {
                free_irq(ab->irq_num_link_status, ab);
        }
}

static int ab8500_usb_v1x_res_setup(struct platform_device *pdev,
                                struct ab8500_usb *ab)
{
        int err;

        ab->irq_num_id_rise = platform_get_irq_byname(pdev, "ID_WAKEUP_R");
        if (ab->irq_num_id_rise < 0) {
                dev_err(&pdev->dev, "ID rise irq not found\n");
                return ab->irq_num_id_rise;
        }
        err = request_threaded_irq(ab->irq_num_id_rise, NULL,
                ab8500_usb_v1x_common_irq,
                IRQF_NO_SUSPEND | IRQF_SHARED,
                "usb-id-rise", ab);
        if (err < 0) {
                dev_err(ab->dev, "request_irq failed for ID rise irq\n");
                goto fail0;
        }

        ab->irq_num_id_fall = platform_get_irq_byname(pdev, "ID_WAKEUP_F");
        if (ab->irq_num_id_fall < 0) {
                dev_err(&pdev->dev, "ID fall irq not found\n");
                return ab->irq_num_id_fall;
        }
        err = request_threaded_irq(ab->irq_num_id_fall, NULL,
                ab8500_usb_v1x_common_irq,
                IRQF_NO_SUSPEND | IRQF_SHARED,
                "usb-id-fall", ab);
        if (err < 0) {
                dev_err(ab->dev, "request_irq failed for ID fall irq\n");
                goto fail1;
        }

        ab->irq_num_vbus_rise = platform_get_irq_byname(pdev, "VBUS_DET_R");
        if (ab->irq_num_vbus_rise < 0) {
                dev_err(&pdev->dev, "VBUS rise irq not found\n");
                return ab->irq_num_vbus_rise;
        }
        err = request_threaded_irq(ab->irq_num_vbus_rise, NULL,
                ab8500_usb_v1x_common_irq,
                IRQF_NO_SUSPEND | IRQF_SHARED,
                "usb-vbus-rise", ab);
        if (err < 0) {
                dev_err(ab->dev, "request_irq failed for Vbus rise irq\n");
                goto fail2;
        }

        ab->irq_num_vbus_fall = platform_get_irq_byname(pdev, "VBUS_DET_F");
        if (ab->irq_num_vbus_fall < 0) {
                dev_err(&pdev->dev, "VBUS fall irq not found\n");
                return ab->irq_num_vbus_fall;
        }
        err = request_threaded_irq(ab->irq_num_vbus_fall, NULL,
                ab8500_usb_v1x_vbus_fall_irq,
                IRQF_NO_SUSPEND | IRQF_SHARED,
                "usb-vbus-fall", ab);
        if (err < 0) {
                dev_err(ab->dev, "request_irq failed for Vbus fall irq\n");
                goto fail3;
        }

        return 0;
fail3:
        free_irq(ab->irq_num_vbus_rise, ab);
fail2:
        free_irq(ab->irq_num_id_fall, ab);
fail1:
        free_irq(ab->irq_num_id_rise, ab);
fail0:
        return err;
}

static int ab8500_usb_v2_res_setup(struct platform_device *pdev,
                                struct ab8500_usb *ab)
{
        int err;

        ab->irq_num_link_status = platform_get_irq_byname(pdev,
                                                "USB_LINK_STATUS");
        if (ab->irq_num_link_status < 0) {
                dev_err(&pdev->dev, "Link status irq not found\n");
                return ab->irq_num_link_status;
        }

        err = request_threaded_irq(ab->irq_num_link_status, NULL,
                ab8500_usb_v20_irq,
                IRQF_NO_SUSPEND | IRQF_SHARED,
                "usb-link-status", ab);
        if (err < 0) {
                dev_err(ab->dev,
                        "request_irq failed for link status irq\n");
                return err;
        }

        return 0;
}

static int __devinit ab8500_usb_probe(struct platform_device *pdev)
{
        struct ab8500_usb       *ab;
        struct usb_otg          *otg;
        int err;
        int rev;

        rev = abx500_get_chip_id(&pdev->dev);
        if (rev < 0) {
                dev_err(&pdev->dev, "Chip id read failed\n");
                return rev;
        } else if (rev < 0x10) {
                dev_err(&pdev->dev, "Unsupported AB8500 chip\n");
                return -ENODEV;
        }

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

        otg = kzalloc(sizeof *otg, GFP_KERNEL);
        if (!otg) {
                kfree(ab);
                return -ENOMEM;
        }

        ab->dev                 = &pdev->dev;
        ab->rev                 = rev;
        ab->phy.dev             = ab->dev;
        ab->phy.otg             = otg;
        ab->phy.label           = "ab8500";
        ab->phy.set_suspend     = ab8500_usb_set_suspend;
        ab->phy.set_power       = ab8500_usb_set_power;
        ab->phy.state           = OTG_STATE_UNDEFINED;

        otg->phy                = &ab->phy;
        otg->set_host           = ab8500_usb_set_host;
        otg->set_peripheral     = ab8500_usb_set_peripheral;

        platform_set_drvdata(pdev, ab);

        ATOMIC_INIT_NOTIFIER_HEAD(&ab->phy.notifier);

        /* v1: Wait for link status to become stable.
         * all: Updates form set_host and set_peripheral as they are atomic.
         */
        INIT_DELAYED_WORK(&ab->dwork, ab8500_usb_delayed_work);

        /* all: Disable phy when called from set_host and set_peripheral */
        INIT_WORK(&ab->phy_dis_work, ab8500_usb_phy_disable_work);

        if (ab->rev < 0x20) {
                err = ab8500_usb_v1x_res_setup(pdev, ab);
                ab->link_status_wait = AB8500_V1x_LINK_STAT_WAIT;
        } else {
                err = ab8500_usb_v2_res_setup(pdev, ab);
        }

        if (err < 0)
                goto fail0;

        err = usb_set_transceiver(&ab->phy);
        if (err) {
                dev_err(&pdev->dev, "Can't register transceiver\n");
                goto fail1;
        }

        dev_info(&pdev->dev, "AB8500 usb driver initialized\n");

        return 0;
fail1:
        ab8500_usb_irq_free(ab);
fail0:
        kfree(otg);
        kfree(ab);
        return err;
}

static int __devexit ab8500_usb_remove(struct platform_device *pdev)
{
        struct ab8500_usb *ab = platform_get_drvdata(pdev);

        ab8500_usb_irq_free(ab);

        cancel_delayed_work_sync(&ab->dwork);

        cancel_work_sync(&ab->phy_dis_work);

        usb_set_transceiver(NULL);

        ab8500_usb_host_phy_dis(ab);
        ab8500_usb_peri_phy_dis(ab);

        platform_set_drvdata(pdev, NULL);

        kfree(ab->phy.otg);
        kfree(ab);

        return 0;
}

static struct platform_driver ab8500_usb_driver = {
        .probe          = ab8500_usb_probe,
        .remove         = __devexit_p(ab8500_usb_remove),
        .driver         = {
                .name   = "ab8500-usb",
                .owner  = THIS_MODULE,
        },
};

static int __init ab8500_usb_init(void)
{
        return platform_driver_register(&ab8500_usb_driver);
}
subsys_initcall(ab8500_usb_init);

static void __exit ab8500_usb_exit(void)
{
        platform_driver_unregister(&ab8500_usb_driver);
}
module_exit(ab8500_usb_exit);

MODULE_ALIAS("platform:ab8500_usb");
MODULE_AUTHOR("ST-Ericsson AB");
MODULE_DESCRIPTION("AB8500 usb transceiver driver");
MODULE_LICENSE("GPL");