/*
   * GPIO based MDIO bitbang driver.
   * Supports OpenFirmware.
   *
   * Copyright (c) 2008 CSE Semaphore Belgium.
   *  by Laurent Pinchart <laurentp@cse-semaphore.com>
   *
   * Copyright (C) 2008, Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
   *
   * Based on earlier work by
   *
   * Copyright (c) 2003 Intracom S.A.
   *  by Pantelis Antoniou <panto@intracom.gr>
   *
   * 2005 (c) MontaVista Software, Inc.
   * Vitaly Bordug <vbordug@ru.mvista.com>
   *
   * 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/interrupt.h>
  #include <linux/platform_device.h>
  #include <linux/gpio.h>
  #include <linux/platform_data/mdio-gpio.h>
  
  #include <linux/of_gpio.h>
  #include <linux/of_mdio.h>
  
  struct mdio_gpio_info {
  	struct mdiobb_ctrl ctrl;
  	int mdc, mdio, mdo;
  	int mdc_active_low, mdio_active_low, mdo_active_low;
  };
  
  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;
  	enum of_gpio_flags flags;
  	int ret;
  
  	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  	if (!pdata)
  		return NULL;
  
  	ret = of_get_gpio_flags(np, 0, &flags);
  	if (ret < 0)
  		return NULL;
  
  	pdata->mdc = ret;
  	pdata->mdc_active_low = flags & OF_GPIO_ACTIVE_LOW;
  
  	ret = of_get_gpio_flags(np, 1, &flags);
  	if (ret < 0)
  		return NULL;
  	pdata->mdio = ret;
  	pdata->mdio_active_low = flags & OF_GPIO_ACTIVE_LOW;
  
  	ret = of_get_gpio_flags(np, 2, &flags);
  	if (ret > 0) {
  		pdata->mdo = ret;
  		pdata->mdo_active_low = flags & OF_GPIO_ACTIVE_LOW;
  	}
  
  	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 (bitbang->mdo) {
  		/* Separate output pin. Always set its value to high
  		 * when changing direction. If direction is input,
  		 * assume the pin serves as pull-up. If direction is
  		 * output, the default value is high.
  		 */
  		gpio_set_value_cansleep(bitbang->mdo,
  					1 ^ bitbang->mdo_active_low);
  		return;
  	}
  
  	if (dir)
  		gpio_direction_output(bitbang->mdio,
  				      1 ^ bitbang->mdio_active_low);
  	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_cansleep(bitbang->mdio) ^
  		bitbang->mdio_active_low;
  }
  
  static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
  {
  	struct mdio_gpio_info *bitbang =
  		container_of(ctrl, struct mdio_gpio_info, ctrl);
  
  	if (bitbang->mdo)
  		gpio_set_value_cansleep(bitbang->mdo,
  					what ^ bitbang->mdo_active_low);
  	else
  		gpio_set_value_cansleep(bitbang->mdio,
  					what ^ bitbang->mdio_active_low);
  }
  
  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_cansleep(bitbang->mdc, what ^ bitbang->mdc_active_low);
  }
  
  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 *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 = devm_kzalloc(dev, sizeof(*bitbang), GFP_KERNEL);
  	if (!bitbang)
  		goto out;
  
  	bitbang->ctrl.ops = &mdio_gpio_ops;
  	bitbang->ctrl.reset = pdata->reset;
  	bitbang->mdc = pdata->mdc;
  	bitbang->mdc_active_low = pdata->mdc_active_low;
  	bitbang->mdio = pdata->mdio;
  	bitbang->mdio_active_low = pdata->mdio_active_low;
  	bitbang->mdo = pdata->mdo;
  	bitbang->mdo_active_low = pdata->mdo_active_low;
  
  	new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
  	if (!new_bus)
  		goto out;
  
  	new_bus->name = "GPIO Bitbanged MDIO",
  
  	new_bus->phy_mask = pdata->phy_mask;
  	new_bus->phy_ignore_ta_mask = pdata->phy_ignore_ta_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;
  
  	if (bus_id != -1)
  		snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
  	else
  		strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE);
  
  	if (devm_gpio_request(dev, bitbang->mdc, "mdc"))
  		goto out_free_bus;
  
  	if (devm_gpio_request(dev, bitbang->mdio, "mdio"))
  		goto out_free_bus;
  
  	if (bitbang->mdo) {
  		if (devm_gpio_request(dev, bitbang->mdo, "mdo"))
  			goto out_free_bus;
  		gpio_direction_output(bitbang->mdo, 1);
  		gpio_direction_input(bitbang->mdio);
  	}
  
  	gpio_direction_output(bitbang->mdc, 0);
  
  	dev_set_drvdata(dev, new_bus);
  
  	return new_bus;
  
  out_free_bus:
  	free_mdio_bitbang(new_bus);
  out:
  	return NULL;
  }
  
  static void mdio_gpio_bus_deinit(struct device *dev)
  {
  	struct mii_bus *bus = dev_get_drvdata(dev);
  
  	free_mdio_bitbang(bus);
  }
  
  static void 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 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");
  		if (bus_id < 0) {
  			dev_warn(&pdev->dev, "failed to get alias id
  ");
  			bus_id = 0;
  		}
  	} else {
  		pdata = dev_get_platdata(&pdev->dev);
  		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 mdio_gpio_remove(struct platform_device *pdev)
  {
  	mdio_gpio_bus_destroy(&pdev->dev);
  
  	return 0;
  }
  
  static const struct of_device_id mdio_gpio_of_match[] = {
  	{ .compatible = "virtual,mdio-gpio", },
  	{ /* sentinel */ }
  };
  MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);
  
  static struct platform_driver mdio_gpio_driver = {
  	.probe = mdio_gpio_probe,
  	.remove = mdio_gpio_remove,
  	.driver		= {
  		.name	= "mdio-gpio",
  		.of_match_table = mdio_gpio_of_match,
  	},
  };
  
  module_platform_driver(mdio_gpio_driver);
  
  MODULE_ALIAS("platform:mdio-gpio");
  MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");