mdio-gpio.c

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/*
 * GPIO based MDIO bitbang driver.
 * Supports OpenFirmware.
 *
 * Copyright (c) 2008 CSE Semaphore Belgium.
 *  by Laurent Pinchart <[email protected]>
 *
 * Copyright (C) 2008, Paulius Zaleckas <[email protected]>
 *
 * Based on earlier work by
 *
 * Copyright (c) 2003 Intracom S.A.
 *  by Pantelis Antoniou <[email protected]>
 *
 * 2005 (c) MontaVista Software, Inc.
 * Vitaly Bordug <[email protected]>
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/mdio-gpio.h>

#include <linux/of_gpio.h>
#include <linux/of_mdio.h>

struct mdio_gpio_info {
    struct mdiobb_ctrl ctrl;
    int mdc, mdio;
};

static void *mdio_gpio_of_get_data(struct platform_device *pdev)
{
    struct device_node *np = pdev->dev.of_node;
    struct mdio_gpio_platform_data *pdata;
    int ret;

    pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
    if (!pdata)
        return NULL;

    ret = of_get_gpio(np, 0);
    if (ret < 0)
        return NULL;

    pdata->mdc = ret;

    ret = of_get_gpio(np, 1);
    if (ret < 0)
        return NULL;
    pdata->mdio = ret;

    return pdata;
}

static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
{
    struct mdio_gpio_info *bitbang =
        container_of(ctrl, struct mdio_gpio_info, ctrl);

    if (dir)
        gpio_direction_output(bitbang->mdio, 1);
    else
        gpio_direction_input(bitbang->mdio);
}

static int mdio_get(struct mdiobb_ctrl *ctrl)
{
    struct mdio_gpio_info *bitbang =
        container_of(ctrl, struct mdio_gpio_info, ctrl);

    return gpio_get_value(bitbang->mdio);
}

static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
{
    struct mdio_gpio_info *bitbang =
        container_of(ctrl, struct mdio_gpio_info, ctrl);

    gpio_set_value(bitbang->mdio, what);
}

static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
{
    struct mdio_gpio_info *bitbang =
        container_of(ctrl, struct mdio_gpio_info, ctrl);

    gpio_set_value(bitbang->mdc, what);
}

static struct mdiobb_ops mdio_gpio_ops = {
    .owner = THIS_MODULE,
    .set_mdc = mdc_set,
    .set_mdio_dir = mdio_dir,
    .set_mdio_data = mdio_set,
    .get_mdio_data = mdio_get,
};

static struct mii_bus * __devinit mdio_gpio_bus_init(struct device *dev,
                    struct mdio_gpio_platform_data *pdata,
                    int bus_id)
{
    struct mii_bus *new_bus;
    struct mdio_gpio_info *bitbang;
    int i;

    bitbang = kzalloc(sizeof(*bitbang), GFP_KERNEL);
    if (!bitbang)
        goto out;

    bitbang->ctrl.ops = &mdio_gpio_ops;
    bitbang->ctrl.reset = pdata->reset;
    bitbang->mdc = pdata->mdc;
    bitbang->mdio = pdata->mdio;

    new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
    if (!new_bus)
        goto out_free_bitbang;

    new_bus->name = "GPIO Bitbanged MDIO",

    new_bus->phy_mask = pdata->phy_mask;
    new_bus->irq = pdata->irqs;
    new_bus->parent = dev;

    if (new_bus->phy_mask == ~0)
        goto out_free_bus;

    for (i = 0; i < PHY_MAX_ADDR; i++)
        if (!new_bus->irq[i])
            new_bus->irq[i] = PHY_POLL;

    snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);

    if (gpio_request(bitbang->mdc, "mdc"))
        goto out_free_bus;

    if (gpio_request(bitbang->mdio, "mdio"))
        goto out_free_mdc;

    gpio_direction_output(bitbang->mdc, 0);

    dev_set_drvdata(dev, new_bus);

    return new_bus;

out_free_mdc:
    gpio_free(bitbang->mdc);
out_free_bus:
    free_mdio_bitbang(new_bus);
out_free_bitbang:
    kfree(bitbang);
out:
    return NULL;
}

static void mdio_gpio_bus_deinit(struct device *dev)
{
    struct mii_bus *bus = dev_get_drvdata(dev);
    struct mdio_gpio_info *bitbang = bus->priv;

    dev_set_drvdata(dev, NULL);
    gpio_free(bitbang->mdio);
    gpio_free(bitbang->mdc);
    free_mdio_bitbang(bus);
    kfree(bitbang);
}

static void __devexit mdio_gpio_bus_destroy(struct device *dev)
{
    struct mii_bus *bus = dev_get_drvdata(dev);

    mdiobus_unregister(bus);
    mdio_gpio_bus_deinit(dev);
}

static int __devinit mdio_gpio_probe(struct platform_device *pdev)
{
    struct mdio_gpio_platform_data *pdata;
    struct mii_bus *new_bus;
    int ret, bus_id;

    if (pdev->dev.of_node) {
        pdata = mdio_gpio_of_get_data(pdev);
        bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");
    } else {
        pdata = pdev->dev.platform_data;
        bus_id = pdev->id;
    }

    if (!pdata)
        return -ENODEV;

    new_bus = mdio_gpio_bus_init(&pdev->dev, pdata, bus_id);
    if (!new_bus)
        return -ENODEV;

    if (pdev->dev.of_node)
        ret = of_mdiobus_register(new_bus, pdev->dev.of_node);
    else
        ret = mdiobus_register(new_bus);

    if (ret)
        mdio_gpio_bus_deinit(&pdev->dev);

    return ret;
}

static int __devexit mdio_gpio_remove(struct platform_device *pdev)
{
    mdio_gpio_bus_destroy(&pdev->dev);

    return 0;
}

static struct of_device_id mdio_gpio_of_match[] = {
    { .compatible = "virtual,mdio-gpio", },
    { /* sentinel */ }
};

static struct platform_driver mdio_gpio_driver = {
    .probe = mdio_gpio_probe,
    .remove = __devexit_p(mdio_gpio_remove),
    .driver     = {
        .name   = "mdio-gpio",
        .owner  = THIS_MODULE,
        .of_match_table = mdio_gpio_of_match,
    },
};

static int __init mdio_gpio_init(void)
{
    return platform_driver_register(&mdio_gpio_driver);
}
module_init(mdio_gpio_init);

static void __exit mdio_gpio_exit(void)
{
    platform_driver_unregister(&mdio_gpio_driver);
}
module_exit(mdio_gpio_exit);

MODULE_ALIAS("platform:mdio-gpio");
MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");