RK3288 OTG 源码

mark83136

/*
* gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
*
* Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.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/kernel.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/usb.h>
#include <linux/workqueue.h>

#include <linux/regulator/consumer.h>

#include <linux/usb/gadget.h>
#include <linux/usb/gpio_vbus.h>
#include <linux/usb/otg.h>


/*
* A simple GPIO VBUS sensing driver for B peripheral only devices
* with internal transceivers. It can control a D+ pullup GPIO and
* a regulator to limit the current drawn from VBUS.
*
* Needs to be loaded before the UDC driver that will use it.
*/
struct gpio_vbus_data {
    struct otg_transceiver otg;
    struct device          *dev;
    struct regulator       *vbus_draw;
    int            vbus_draw_enabled;
    unsigned        mA;
    struct work_struct    work;
};


/*
* This driver relies on "both edges" triggering.  VBUS has 100 msec to
* stabilize, so the peripheral controller driver may need to cope with
* some bouncing due to current surges (e.g. charging local capacitance)
* and contact chatter.
*
* REVISIT in desperate straits, toggling between rising and falling
* edges might be workable.
*/
#define VBUS_IRQ_FLAGS \
    ( IRQF_SAMPLE_RANDOM | IRQF_SHARED \
    | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING )


/* interface to regulator framework */
static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
{
    struct regulator *vbus_draw = gpio_vbus->vbus_draw;
    int enabled;

    if (!vbus_draw)
        return;

    enabled = gpio_vbus->vbus_draw_enabled;
    if (mA) {
        regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
        if (!enabled) {
            regulator_enable(vbus_draw);
            gpio_vbus->vbus_draw_enabled = 1;
        }
    } else {
        if (enabled) {
            regulator_disable(vbus_draw);
            gpio_vbus->vbus_draw_enabled = 0;
        }
    }
    gpio_vbus->mA = mA;
}

static int is_vbus_powered(struct gpio_vbus_mach_info *pdata)
{
    int vbus;

    vbus = gpio_get_value(pdata->gpio_vbus);
    if (pdata->gpio_vbus_inverted)
        vbus = !vbus;

    return vbus;
}

static void gpio_vbus_work(struct work_struct *work)
{
    struct gpio_vbus_data *gpio_vbus =
        container_of(work, struct gpio_vbus_data, work);
    struct gpio_vbus_mach_info *pdata = gpio_vbus->dev->platform_data;
    int gpio;

    if (!gpio_vbus->otg.gadget)
        return;

    /* Peripheral controllers which manage the pullup themselves won't have
     * gpio_pullup configured here.  If it's configured here, we'll do what
     * isp1301_omap::b_peripheral() does and enable the pullup here... although
     * that may complicate usb_gadget_{,dis}connect() support.
     */
    gpio = pdata->gpio_pullup;
    if (is_vbus_powered(pdata)) {
        gpio_vbus->otg.state = OTG_STATE_B_PERIPHERAL;
        usb_gadget_vbus_connect(gpio_vbus->otg.gadget);

        /* drawing a "unit load" is *always* OK, except for OTG */
        set_vbus_draw(gpio_vbus, 100);

        /* optionally enable D+ pullup */
        if (gpio_is_valid(gpio))
            gpio_set_value(gpio, !pdata->gpio_pullup_inverted);
    } else {
        /* optionally disable D+ pullup */
        if (gpio_is_valid(gpio))
            gpio_set_value(gpio, pdata->gpio_pullup_inverted);

        set_vbus_draw(gpio_vbus, 0);

        usb_gadget_vbus_disconnect(gpio_vbus->otg.gadget);
        gpio_vbus->otg.state = OTG_STATE_B_IDLE;
    }
}

/* VBUS change IRQ handler */
static irqreturn_t gpio_vbus_irq(int irq, void *data)
{
    struct platform_device *pdev = data;
    struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
    struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);

    dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
        is_vbus_powered(pdata) ? "supplied" : "inactive",
        gpio_vbus->otg.gadget ? gpio_vbus->otg.gadget->name : "none");

    if (gpio_vbus->otg.gadget)
        schedule_work(&gpio_vbus->work);

    return IRQ_HANDLED;
}

/* OTG transceiver interface */

/* bind/unbind the peripheral controller */
static int gpio_vbus_set_peripheral(struct otg_transceiver *otg,
                struct usb_gadget *gadget)
{
    struct gpio_vbus_data *gpio_vbus;
    struct gpio_vbus_mach_info *pdata;
    struct platform_device *pdev;
    int gpio, irq;

    gpio_vbus = container_of(otg, struct gpio_vbus_data, otg);
    pdev = to_platform_device(gpio_vbus->dev);
    pdata = gpio_vbus->dev->platform_data;
    irq = gpio_to_irq(pdata->gpio_vbus);
    gpio = pdata->gpio_pullup;

    if (!gadget) {
        dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
            otg->gadget->name);

        /* optionally disable D+ pullup */
        if (gpio_is_valid(gpio))
            gpio_set_value(gpio, pdata->gpio_pullup_inverted);

        set_vbus_draw(gpio_vbus, 0);

        usb_gadget_vbus_disconnect(otg->gadget);
        otg->state = OTG_STATE_UNDEFINED;

        otg->gadget = NULL;
        return 0;
    }

    otg->gadget = gadget;
    dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);

    /* initialize connection state */
    gpio_vbus_irq(irq, pdev);
    return 0;
}

/* effective for B devices, ignored for A-peripheral */
static int gpio_vbus_set_power(struct otg_transceiver *otg, unsigned mA)
{
    struct gpio_vbus_data *gpio_vbus;

    gpio_vbus = container_of(otg, struct gpio_vbus_data, otg);

    if (otg->state == OTG_STATE_B_PERIPHERAL)
        set_vbus_draw(gpio_vbus, mA);
    return 0;
}

/* for non-OTG B devices: set/clear transceiver suspend mode */
static int gpio_vbus_set_suspend(struct otg_transceiver *otg, int suspend)
{
    struct gpio_vbus_data *gpio_vbus;

    gpio_vbus = container_of(otg, struct gpio_vbus_data, otg);

    /* draw max 0 mA from vbus in suspend mode; or the previously
     * recorded amount of current if not suspended
     *
     * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
     * if they're wake-enabled ... we don't handle that yet.
     */
    return gpio_vbus_set_power(otg, suspend ? 0 : gpio_vbus->mA);
}

/* platform driver interface */

static int __init gpio_vbus_probe(struct platform_device *pdev)
{
    struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
    struct gpio_vbus_data *gpio_vbus;
    struct resource *res;
    int err, gpio, irq;

    if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
        return -EINVAL;
    gpio = pdata->gpio_vbus;

    gpio_vbus = kzalloc(sizeof(struct gpio_vbus_data), GFP_KERNEL);
    if (!gpio_vbus)
        return -ENOMEM;

    platform_set_drvdata(pdev, gpio_vbus);
    gpio_vbus->dev = &pdev->dev;
    gpio_vbus->otg.label = "gpio-vbus";
    gpio_vbus->otg.state = OTG_STATE_UNDEFINED;
    gpio_vbus->otg.set_peripheral = gpio_vbus_set_peripheral;
    gpio_vbus->otg.set_power = gpio_vbus_set_power;
    gpio_vbus->otg.set_suspend = gpio_vbus_set_suspend;

    err = gpio_request(gpio, "vbus_detect");
    if (err) {
        dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
            gpio, err);
        goto err_gpio;
    }
    gpio_direction_input(gpio);

    res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
    if (res) {
        irq = res->start;
        res->flags &= IRQF_TRIGGER_MASK;
        res->flags |= IRQF_SAMPLE_RANDOM | IRQF_SHARED;
    } else
        irq = gpio_to_irq(gpio);

    /* if data line pullup is in use, initialize it to "not pulling up" */
    gpio = pdata->gpio_pullup;
    if (gpio_is_valid(gpio)) {
        err = gpio_request(gpio, "udc_pullup");
        if (err) {
            dev_err(&pdev->dev,
                "can't request pullup gpio %d, err: %d\n",
                gpio, err);
            gpio_free(pdata->gpio_vbus);
            goto err_gpio;
        }
        gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
    }

    err = request_irq(irq, gpio_vbus_irq, VBUS_IRQ_FLAGS,
        "vbus_detect", pdev);
    if (err) {
        dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
            irq, err);
        goto err_irq;
    }
    INIT_WORK(&gpio_vbus->work, gpio_vbus_work);

    gpio_vbus->vbus_draw = regulator_get(&pdev->dev, "vbus_draw");
    if (IS_ERR(gpio_vbus->vbus_draw)) {
        dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
            PTR_ERR(gpio_vbus->vbus_draw));
        gpio_vbus->vbus_draw = NULL;
    }

    /* only active when a gadget is registered */
    err = otg_set_transceiver(&gpio_vbus->otg);
    if (err) {
        dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
            err);
        goto err_otg;
    }

    return 0;
err_otg:
    free_irq(irq, &pdev->dev);
err_irq:
    if (gpio_is_valid(pdata->gpio_pullup))
        gpio_free(pdata->gpio_pullup);
    gpio_free(pdata->gpio_vbus);
err_gpio:
    platform_set_drvdata(pdev, NULL);
    kfree(gpio_vbus);
    return err;
}

static int __exit gpio_vbus_remove(struct platform_device *pdev)
{
    struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
    struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
    int gpio = pdata->gpio_vbus;

    regulator_put(gpio_vbus->vbus_draw);

    otg_set_transceiver(NULL);

    free_irq(gpio_to_irq(gpio), &pdev->dev);
    if (gpio_is_valid(pdata->gpio_pullup))
        gpio_free(pdata->gpio_pullup);
    gpio_free(gpio);
    platform_set_drvdata(pdev, NULL);
    kfree(gpio_vbus);

    return 0;
}

/* NOTE:  the gpio-vbus device may *NOT* be hotplugged */

MODULE_ALIAS("platform:gpio-vbus");

static struct platform_driver gpio_vbus_driver = {
    .driver = {
        .name  = "gpio-vbus",
        .owner = THIS_MODULE,
    },
    .remove  = __exit_p(gpio_vbus_remove),
};

static int __init gpio_vbus_init(void)
{
    return platform_driver_probe(&gpio_vbus_driver, gpio_vbus_probe);
}
module_init(gpio_vbus_init);

static void __exit gpio_vbus_exit(void)
{
    platform_driver_unregister(&gpio_vbus_driver);
}
module_exit(gpio_vbus_exit);

MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
MODULE_AUTHOR(&quothilipp Zabel");
MODULE_LICENSE("GPL");