/**
 * ulpi.c - USB ULPI PHY bus
 *
 * Copyright (C) 2015 Intel Corporation
 *
 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.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/ulpi/interface.h>
#include <linux/ulpi/driver.h>
#include <linux/ulpi/regs.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/acpi.h>

/* -------------------------------------------------------------------------- */

int ulpi_read(struct ulpi *ulpi, u8 addr)
{
        return ulpi->ops->read(ulpi->dev.parent, addr);
}
EXPORT_SYMBOL_GPL(ulpi_read);

int ulpi_write(struct ulpi *ulpi, u8 addr, u8 val)
{
        return ulpi->ops->write(ulpi->dev.parent, addr, val);
}
EXPORT_SYMBOL_GPL(ulpi_write);

/* -------------------------------------------------------------------------- */

static int ulpi_match(struct device *dev, struct device_driver *driver)
{
        struct ulpi_driver *drv = to_ulpi_driver(driver);
        struct ulpi *ulpi = to_ulpi_dev(dev);
        const struct ulpi_device_id *id;

        for (id = drv->id_table; id->vendor; id++)
                if (id->vendor == ulpi->id.vendor &&
                    id->product == ulpi->id.product)
                        return 1;

        return 0;
}

static int ulpi_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct ulpi *ulpi = to_ulpi_dev(dev);

        if (add_uevent_var(env, "MODALIAS=ulpi:v%04xp%04x",
                           ulpi->id.vendor, ulpi->id.product))
                return -ENOMEM;
        return 0;
}

static int ulpi_probe(struct device *dev)
{
        struct ulpi_driver *drv = to_ulpi_driver(dev->driver);

        return drv->probe(to_ulpi_dev(dev));
}

static int ulpi_remove(struct device *dev)
{
        struct ulpi_driver *drv = to_ulpi_driver(dev->driver);

        if (drv->remove)
                drv->remove(to_ulpi_dev(dev));

        return 0;
}

static struct bus_type ulpi_bus = {
        .name = "ulpi",
        .match = ulpi_match,
        .uevent = ulpi_uevent,
        .probe = ulpi_probe,
        .remove = ulpi_remove,
};

/* -------------------------------------------------------------------------- */

static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
                             char *buf)
{
        struct ulpi *ulpi = to_ulpi_dev(dev);

        return sprintf(buf, "ulpi:v%04xp%04x\n",
                       ulpi->id.vendor, ulpi->id.product);
}
static DEVICE_ATTR_RO(modalias);

static struct attribute *ulpi_dev_attrs[] = {
        &dev_attr_modalias.attr,
        NULL
};

static struct attribute_group ulpi_dev_attr_group = {
        .attrs = ulpi_dev_attrs,
};

static const struct attribute_group *ulpi_dev_attr_groups[] = {
        &ulpi_dev_attr_group,
        NULL
};

static void ulpi_dev_release(struct device *dev)
{
        kfree(to_ulpi_dev(dev));
}

static struct device_type ulpi_dev_type = {
        .name = "ulpi_device",
        .groups = ulpi_dev_attr_groups,
        .release = ulpi_dev_release,
};

/* -------------------------------------------------------------------------- */

/**
 * ulpi_register_driver - register a driver with the ULPI bus
 * @drv: driver being registered
 *
 * Registers a driver with the ULPI bus.
 */
int __ulpi_register_driver(struct ulpi_driver *drv, struct module *module)
{
        if (!drv->probe)
                return -EINVAL;

        drv->driver.owner = module;
        drv->driver.bus = &ulpi_bus;

        return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(__ulpi_register_driver);

/**
 * ulpi_unregister_driver - unregister a driver with the ULPI bus
 * @drv: driver to unregister
 *
 * Unregisters a driver with the ULPI bus.
 */
void ulpi_unregister_driver(struct ulpi_driver *drv)
{
        driver_unregister(&drv->driver);
}
EXPORT_SYMBOL_GPL(ulpi_unregister_driver);

/* -------------------------------------------------------------------------- */

static int ulpi_register(struct device *dev, struct ulpi *ulpi)
{
        int ret;

        ulpi->dev.parent = dev; /* needed early for ops */

        /* Test the interface */
        ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa);
        if (ret < 0)
                return ret;

        ret = ulpi_read(ulpi, ULPI_SCRATCH);
        if (ret < 0)
                return ret;

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

        ulpi->id.vendor = ulpi_read(ulpi, ULPI_VENDOR_ID_LOW);
        ulpi->id.vendor |= ulpi_read(ulpi, ULPI_VENDOR_ID_HIGH) << 8;

        ulpi->id.product = ulpi_read(ulpi, ULPI_PRODUCT_ID_LOW);
        ulpi->id.product |= ulpi_read(ulpi, ULPI_PRODUCT_ID_HIGH) << 8;

        ulpi->dev.bus = &ulpi_bus;
        ulpi->dev.type = &ulpi_dev_type;
        dev_set_name(&ulpi->dev, "%s.ulpi", dev_name(dev));

        ACPI_COMPANION_SET(&ulpi->dev, ACPI_COMPANION(dev));

        request_module("ulpi:v%04xp%04x", ulpi->id.vendor, ulpi->id.product);

        ret = device_register(&ulpi->dev);
        if (ret)
                return ret;

        dev_dbg(&ulpi->dev, "registered ULPI PHY: vendor %04x, product %04x\n",
                ulpi->id.vendor, ulpi->id.product);

        return 0;
}

/**
 * ulpi_register_interface - instantiate new ULPI device
 * @dev: USB controller's device interface
 * @ops: ULPI register access
 *
 * Allocates and registers a ULPI device and an interface for it. Called from
 * the USB controller that provides the ULPI interface.
 */
struct ulpi *ulpi_register_interface(struct device *dev,
                                     const struct ulpi_ops *ops)
{
        struct ulpi *ulpi;
        int ret;

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

        ulpi->ops = ops;

        ret = ulpi_register(dev, ulpi);
        if (ret) {
                kfree(ulpi);
                return ERR_PTR(ret);
        }

        return ulpi;
}
EXPORT_SYMBOL_GPL(ulpi_register_interface);

/**
 * ulpi_unregister_interface - unregister ULPI interface
 * @intrf: struct ulpi_interface
 *
 * Unregisters a ULPI device and it's interface that was created with
 * ulpi_create_interface().
 */
void ulpi_unregister_interface(struct ulpi *ulpi)
{
        device_unregister(&ulpi->dev);
}
EXPORT_SYMBOL_GPL(ulpi_unregister_interface);

/* -------------------------------------------------------------------------- */

static int __init ulpi_init(void)
{
        return bus_register(&ulpi_bus);
}
subsys_initcall(ulpi_init);

static void __exit ulpi_exit(void)
{
        bus_unregister(&ulpi_bus);
}
module_exit(ulpi_exit);

MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("USB ULPI PHY bus");