isp1704_charger.c

Go to the documentation of this file.

/*
 * ISP1704 USB Charger Detection driver
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/device.h>
#include <linux/sysfs.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/delay.h>

#include <linux/usb/otg.h>
#include <linux/usb/ulpi.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/power/isp1704_charger.h>

/* Vendor specific Power Control register */
#define ISP1704_PWR_CTRL        0x3d
#define ISP1704_PWR_CTRL_SWCTRL     (1 << 0)
#define ISP1704_PWR_CTRL_DET_COMP   (1 << 1)
#define ISP1704_PWR_CTRL_BVALID_RISE    (1 << 2)
#define ISP1704_PWR_CTRL_BVALID_FALL    (1 << 3)
#define ISP1704_PWR_CTRL_DP_WKPU_EN (1 << 4)
#define ISP1704_PWR_CTRL_VDAT_DET   (1 << 5)
#define ISP1704_PWR_CTRL_DPVSRC_EN  (1 << 6)
#define ISP1704_PWR_CTRL_HWDETECT   (1 << 7)

#define NXP_VENDOR_ID           0x04cc

static u16 isp170x_id[] = {
    0x1704,
    0x1707,
};

struct isp1704_charger {
    struct device       *dev;
    struct power_supply psy;
    struct usb_phy      *phy;
    struct notifier_block   nb;
    struct work_struct  work;

    /* properties */
    char            model[8];
    unsigned        present:1;
    unsigned        online:1;
    unsigned        current_max;

    /* temp storage variables */
    unsigned long       event;
    unsigned        max_power;
};

static inline int isp1704_read(struct isp1704_charger *isp, u32 reg)
{
    return usb_phy_io_read(isp->phy, reg);
}

static inline int isp1704_write(struct isp1704_charger *isp, u32 val, u32 reg)
{
    return usb_phy_io_write(isp->phy, val, reg);
}

/*
 * Disable/enable the power from the isp1704 if a function for it
 * has been provided with platform data.
 */
static void isp1704_charger_set_power(struct isp1704_charger *isp, bool on)
{
    struct isp1704_charger_data *board = isp->dev->platform_data;

    if (board && board->set_power)
        board->set_power(on);
}

/*
 * Determine is the charging port DCP (dedicated charger) or CDP (Host/HUB
 * chargers).
 *
 * REVISIT: The method is defined in Battery Charging Specification and is
 * applicable to any ULPI transceiver. Nothing isp170x specific here.
 */
static inline int isp1704_charger_type(struct isp1704_charger *isp)
{
    u8 reg;
    u8 func_ctrl;
    u8 otg_ctrl;
    int type = POWER_SUPPLY_TYPE_USB_DCP;

    func_ctrl = isp1704_read(isp, ULPI_FUNC_CTRL);
    otg_ctrl = isp1704_read(isp, ULPI_OTG_CTRL);

    /* disable pulldowns */
    reg = ULPI_OTG_CTRL_DM_PULLDOWN | ULPI_OTG_CTRL_DP_PULLDOWN;
    isp1704_write(isp, ULPI_CLR(ULPI_OTG_CTRL), reg);

    /* full speed */
    isp1704_write(isp, ULPI_CLR(ULPI_FUNC_CTRL),
            ULPI_FUNC_CTRL_XCVRSEL_MASK);
    isp1704_write(isp, ULPI_SET(ULPI_FUNC_CTRL),
            ULPI_FUNC_CTRL_FULL_SPEED);

    /* Enable strong pull-up on DP (1.5K) and reset */
    reg = ULPI_FUNC_CTRL_TERMSELECT | ULPI_FUNC_CTRL_RESET;
    isp1704_write(isp, ULPI_SET(ULPI_FUNC_CTRL), reg);
    usleep_range(1000, 2000);

    reg = isp1704_read(isp, ULPI_DEBUG);
    if ((reg & 3) != 3)
        type = POWER_SUPPLY_TYPE_USB_CDP;

    /* recover original state */
    isp1704_write(isp, ULPI_FUNC_CTRL, func_ctrl);
    isp1704_write(isp, ULPI_OTG_CTRL, otg_ctrl);

    return type;
}

/*
 * ISP1704 detects PS/2 adapters as charger. To make sure the detected charger
 * is actually a dedicated charger, the following steps need to be taken.
 */
static inline int isp1704_charger_verify(struct isp1704_charger *isp)
{
    int ret = 0;
    u8  r;

    /* Reset the transceiver */
    r = isp1704_read(isp, ULPI_FUNC_CTRL);
    r |= ULPI_FUNC_CTRL_RESET;
    isp1704_write(isp, ULPI_FUNC_CTRL, r);
    usleep_range(1000, 2000);

    /* Set normal mode */
    r &= ~(ULPI_FUNC_CTRL_RESET | ULPI_FUNC_CTRL_OPMODE_MASK);
    isp1704_write(isp, ULPI_FUNC_CTRL, r);

    /* Clear the DP and DM pull-down bits */
    r = ULPI_OTG_CTRL_DP_PULLDOWN | ULPI_OTG_CTRL_DM_PULLDOWN;
    isp1704_write(isp, ULPI_CLR(ULPI_OTG_CTRL), r);

    /* Enable strong pull-up on DP (1.5K) and reset */
    r = ULPI_FUNC_CTRL_TERMSELECT | ULPI_FUNC_CTRL_RESET;
    isp1704_write(isp, ULPI_SET(ULPI_FUNC_CTRL), r);
    usleep_range(1000, 2000);

    /* Read the line state */
    if (!isp1704_read(isp, ULPI_DEBUG)) {
        /* Disable strong pull-up on DP (1.5K) */
        isp1704_write(isp, ULPI_CLR(ULPI_FUNC_CTRL),
                ULPI_FUNC_CTRL_TERMSELECT);
        return 1;
    }

    /* Is it a charger or PS/2 connection */

    /* Enable weak pull-up resistor on DP */
    isp1704_write(isp, ULPI_SET(ISP1704_PWR_CTRL),
            ISP1704_PWR_CTRL_DP_WKPU_EN);

    /* Disable strong pull-up on DP (1.5K) */
    isp1704_write(isp, ULPI_CLR(ULPI_FUNC_CTRL),
            ULPI_FUNC_CTRL_TERMSELECT);

    /* Enable weak pull-down resistor on DM */
    isp1704_write(isp, ULPI_SET(ULPI_OTG_CTRL),
            ULPI_OTG_CTRL_DM_PULLDOWN);

    /* It's a charger if the line states are clear */
    if (!(isp1704_read(isp, ULPI_DEBUG)))
        ret = 1;

    /* Disable weak pull-up resistor on DP */
    isp1704_write(isp, ULPI_CLR(ISP1704_PWR_CTRL),
            ISP1704_PWR_CTRL_DP_WKPU_EN);

    return ret;
}

static inline int isp1704_charger_detect(struct isp1704_charger *isp)
{
    unsigned long   timeout;
    u8      pwr_ctrl;
    int     ret = 0;

    pwr_ctrl = isp1704_read(isp, ISP1704_PWR_CTRL);

    /* set SW control bit in PWR_CTRL register */
    isp1704_write(isp, ISP1704_PWR_CTRL,
            ISP1704_PWR_CTRL_SWCTRL);

    /* enable manual charger detection */
    isp1704_write(isp, ULPI_SET(ISP1704_PWR_CTRL),
            ISP1704_PWR_CTRL_SWCTRL
            | ISP1704_PWR_CTRL_DPVSRC_EN);
    usleep_range(1000, 2000);

    timeout = jiffies + msecs_to_jiffies(300);
    do {
        /* Check if there is a charger */
        if (isp1704_read(isp, ISP1704_PWR_CTRL)
                & ISP1704_PWR_CTRL_VDAT_DET) {
            ret = isp1704_charger_verify(isp);
            break;
        }
    } while (!time_after(jiffies, timeout) && isp->online);

    /* recover original state */
    isp1704_write(isp, ISP1704_PWR_CTRL, pwr_ctrl);

    return ret;
}

static void isp1704_charger_work(struct work_struct *data)
{
    int         detect;
    unsigned long       event;
    unsigned        power;
    struct isp1704_charger  *isp =
        container_of(data, struct isp1704_charger, work);
    static DEFINE_MUTEX(lock);

    event = isp->event;
    power = isp->max_power;

    mutex_lock(&lock);

    if (event != USB_EVENT_NONE)
        isp1704_charger_set_power(isp, 1);

    switch (event) {
    case USB_EVENT_VBUS:
        isp->online = true;

        /* detect charger */
        detect = isp1704_charger_detect(isp);

        if (detect) {
            isp->present = detect;
            isp->psy.type = isp1704_charger_type(isp);
        }

        switch (isp->psy.type) {
        case POWER_SUPPLY_TYPE_USB_DCP:
            isp->current_max = 1800;
            break;
        case POWER_SUPPLY_TYPE_USB_CDP:
            /*
             * Only 500mA here or high speed chirp
             * handshaking may break
             */
            isp->current_max = 500;
            /* FALLTHROUGH */
        case POWER_SUPPLY_TYPE_USB:
        default:
            /* enable data pullups */
            if (isp->phy->otg->gadget)
                usb_gadget_connect(isp->phy->otg->gadget);
        }
        break;
    case USB_EVENT_NONE:
        isp->online = false;
        isp->current_max = 0;
        isp->present = 0;
        isp->current_max = 0;
        isp->psy.type = POWER_SUPPLY_TYPE_USB;

        /*
         * Disable data pullups. We need to prevent the controller from
         * enumerating.
         *
         * FIXME: This is here to allow charger detection with Host/HUB
         * chargers. The pullups may be enabled elsewhere, so this can
         * not be the final solution.
         */
        if (isp->phy->otg->gadget)
            usb_gadget_disconnect(isp->phy->otg->gadget);

        isp1704_charger_set_power(isp, 0);
        break;
    case USB_EVENT_ENUMERATED:
        if (isp->present)
            isp->current_max = 1800;
        else
            isp->current_max = power;
        break;
    default:
        goto out;
    }

    power_supply_changed(&isp->psy);
out:
    mutex_unlock(&lock);
}

static int isp1704_notifier_call(struct notifier_block *nb,
        unsigned long event, void *power)
{
    struct isp1704_charger *isp =
        container_of(nb, struct isp1704_charger, nb);

    isp->event = event;

    if (power)
        isp->max_power = *((unsigned *)power);

    schedule_work(&isp->work);

    return NOTIFY_OK;
}

static int isp1704_charger_get_property(struct power_supply *psy,
                enum power_supply_property psp,
                union power_supply_propval *val)
{
    struct isp1704_charger *isp =
        container_of(psy, struct isp1704_charger, psy);

    switch (psp) {
    case POWER_SUPPLY_PROP_PRESENT:
        val->intval = isp->present;
        break;
    case POWER_SUPPLY_PROP_ONLINE:
        val->intval = isp->online;
        break;
    case POWER_SUPPLY_PROP_CURRENT_MAX:
        val->intval = isp->current_max;
        break;
    case POWER_SUPPLY_PROP_MODEL_NAME:
        val->strval = isp->model;
        break;
    case POWER_SUPPLY_PROP_MANUFACTURER:
        val->strval = "NXP";
        break;
    default:
        return -EINVAL;
    }
    return 0;
}

static enum power_supply_property power_props[] = {
    POWER_SUPPLY_PROP_PRESENT,
    POWER_SUPPLY_PROP_ONLINE,
    POWER_SUPPLY_PROP_CURRENT_MAX,
    POWER_SUPPLY_PROP_MODEL_NAME,
    POWER_SUPPLY_PROP_MANUFACTURER,
};

static inline int isp1704_test_ulpi(struct isp1704_charger *isp)
{
    int vendor;
    int product;
    int i;
    int ret = -ENODEV;

    /* Test ULPI interface */
    ret = isp1704_write(isp, ULPI_SCRATCH, 0xaa);
    if (ret < 0)
        return ret;

    ret = isp1704_read(isp, ULPI_SCRATCH);
    if (ret < 0)
        return ret;

    if (ret != 0xaa)
        return -ENODEV;

    /* Verify the product and vendor id matches */
    vendor = isp1704_read(isp, ULPI_VENDOR_ID_LOW);
    vendor |= isp1704_read(isp, ULPI_VENDOR_ID_HIGH) << 8;
    if (vendor != NXP_VENDOR_ID)
        return -ENODEV;

    product = isp1704_read(isp, ULPI_PRODUCT_ID_LOW);
    product |= isp1704_read(isp, ULPI_PRODUCT_ID_HIGH) << 8;

    for (i = 0; i < ARRAY_SIZE(isp170x_id); i++) {
        if (product == isp170x_id[i]) {
            sprintf(isp->model, "isp%x", product);
            return product;
        }
    }

    dev_err(isp->dev, "product id %x not matching known ids", product);

    return -ENODEV;
}

static int __devinit isp1704_charger_probe(struct platform_device *pdev)
{
    struct isp1704_charger  *isp;
    int         ret = -ENODEV;

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

    isp->phy = usb_get_phy(USB_PHY_TYPE_USB2);
    if (IS_ERR_OR_NULL(isp->phy))
        goto fail0;

    isp->dev = &pdev->dev;
    platform_set_drvdata(pdev, isp);

    isp1704_charger_set_power(isp, 1);

    ret = isp1704_test_ulpi(isp);
    if (ret < 0)
        goto fail1;

    isp->psy.name       = "isp1704";
    isp->psy.type       = POWER_SUPPLY_TYPE_USB;
    isp->psy.properties = power_props;
    isp->psy.num_properties = ARRAY_SIZE(power_props);
    isp->psy.get_property   = isp1704_charger_get_property;

    ret = power_supply_register(isp->dev, &isp->psy);
    if (ret)
        goto fail1;

    /*
     * REVISIT: using work in order to allow the usb notifications to be
     * made atomically in the future.
     */
    INIT_WORK(&isp->work, isp1704_charger_work);

    isp->nb.notifier_call = isp1704_notifier_call;

    ret = usb_register_notifier(isp->phy, &isp->nb);
    if (ret)
        goto fail2;

    dev_info(isp->dev, "registered with product id %s\n", isp->model);

    /*
     * Taking over the D+ pullup.
     *
     * FIXME: The device will be disconnected if it was already
     * enumerated. The charger driver should be always loaded before any
     * gadget is loaded.
     */
    if (isp->phy->otg->gadget)
        usb_gadget_disconnect(isp->phy->otg->gadget);

    /* Detect charger if VBUS is valid (the cable was already plugged). */
    ret = isp1704_read(isp, ULPI_USB_INT_STS);
    isp1704_charger_set_power(isp, 0);
    if ((ret & ULPI_INT_VBUS_VALID) && !isp->phy->otg->default_a) {
        isp->event = USB_EVENT_VBUS;
        schedule_work(&isp->work);
    }

    return 0;
fail2:
    power_supply_unregister(&isp->psy);
fail1:
    isp1704_charger_set_power(isp, 0);
    usb_put_phy(isp->phy);
fail0:
    kfree(isp);

    dev_err(&pdev->dev, "failed to register isp1704 with error %d\n", ret);

    return ret;
}

static int __devexit isp1704_charger_remove(struct platform_device *pdev)
{
    struct isp1704_charger *isp = platform_get_drvdata(pdev);

    usb_unregister_notifier(isp->phy, &isp->nb);
    power_supply_unregister(&isp->psy);
    usb_put_phy(isp->phy);
    isp1704_charger_set_power(isp, 0);
    kfree(isp);

    return 0;
}

static struct platform_driver isp1704_charger_driver = {
    .driver = {
        .name = "isp1704_charger",
    },
    .probe = isp1704_charger_probe,
    .remove = __devexit_p(isp1704_charger_remove),
};

module_platform_driver(isp1704_charger_driver);

MODULE_ALIAS("platform:isp1704_charger");
MODULE_AUTHOR("Nokia Corporation");
MODULE_DESCRIPTION("ISP170x USB Charger driver");
MODULE_LICENSE("GPL");