/*
 * OMAP OTG controller driver
 *
 * Based on code from tahvo-usb.c and isp1301_omap.c drivers.
 *
 * Copyright (C) 2005-2006 Nokia Corporation
 * Copyright (C) 2004 Texas Instruments
 * Copyright (C) 2004 David Brownell
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License. See the file "COPYING" in the main directory of this
 * archive for more details.
 *
 * 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.
 */

#include <linux/io.h>
#include <linux/err.h>
#include <linux/extcon.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/platform_data/usb-omap1.h>

struct otg_device {
	void __iomem			*base;
	bool				id;
	bool				vbus;
	struct extcon_specific_cable_nb	vbus_dev;
	struct extcon_specific_cable_nb	id_dev;
	struct notifier_block		vbus_nb;
	struct notifier_block		id_nb;
};

#define OMAP_OTG_CTRL		0x0c
#define OMAP_OTG_ASESSVLD	(1 << 20)
#define OMAP_OTG_BSESSEND	(1 << 19)
#define OMAP_OTG_BSESSVLD	(1 << 18)
#define OMAP_OTG_VBUSVLD	(1 << 17)
#define OMAP_OTG_ID		(1 << 16)
#define OMAP_OTG_XCEIV_OUTPUTS \
	(OMAP_OTG_ASESSVLD | OMAP_OTG_BSESSEND | OMAP_OTG_BSESSVLD | \
	 OMAP_OTG_VBUSVLD  | OMAP_OTG_ID)

static void omap_otg_ctrl(struct otg_device *otg_dev, u32 outputs)
{
	u32 l;

	l = readl(otg_dev->base + OMAP_OTG_CTRL);
	l &= ~OMAP_OTG_XCEIV_OUTPUTS;
	l |= outputs;
	writel(l, otg_dev->base + OMAP_OTG_CTRL);
}

static void omap_otg_set_mode(struct otg_device *otg_dev)
{
	if (!otg_dev->id && otg_dev->vbus)
		/* Set B-session valid. */
		omap_otg_ctrl(otg_dev, OMAP_OTG_ID | OMAP_OTG_BSESSVLD);
	else if (otg_dev->vbus)
		/* Set A-session valid. */
		omap_otg_ctrl(otg_dev, OMAP_OTG_ASESSVLD);
	else if (!otg_dev->id)
		/* Set B-session end to indicate no VBUS. */
		omap_otg_ctrl(otg_dev, OMAP_OTG_ID | OMAP_OTG_BSESSEND);
}

static int omap_otg_id_notifier(struct notifier_block *nb,
				unsigned long event, void *ptr)
{
	struct otg_device *otg_dev = container_of(nb, struct otg_device, id_nb);

	otg_dev->id = event;
	omap_otg_set_mode(otg_dev);

	return NOTIFY_DONE;
}

static int omap_otg_vbus_notifier(struct notifier_block *nb,
				  unsigned long event, void *ptr)
{
	struct otg_device *otg_dev = container_of(nb, struct otg_device,
						  vbus_nb);

	otg_dev->vbus = event;
	omap_otg_set_mode(otg_dev);

	return NOTIFY_DONE;
}

static int omap_otg_probe(struct platform_device *pdev)
{
	const struct omap_usb_config *config = pdev->dev.platform_data;
	struct otg_device *otg_dev;
	struct extcon_dev *extcon;
	int ret;
	u32 rev;

	if (!config || !config->extcon)
		return -ENODEV;

	extcon = extcon_get_extcon_dev(config->extcon);
	if (!extcon)
		return -EPROBE_DEFER;

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

	otg_dev->base = devm_ioremap_resource(&pdev->dev, &pdev->resource[0]);
	if (IS_ERR(otg_dev->base))
		return PTR_ERR(otg_dev->base);

	otg_dev->id_nb.notifier_call = omap_otg_id_notifier;
	otg_dev->vbus_nb.notifier_call = omap_otg_vbus_notifier;

	ret = extcon_register_interest(&otg_dev->id_dev, config->extcon,
				       "USB-HOST", &otg_dev->id_nb);
	if (ret)
		return ret;

	ret = extcon_register_interest(&otg_dev->vbus_dev, config->extcon,
				       "USB", &otg_dev->vbus_nb);
	if (ret) {
		extcon_unregister_interest(&otg_dev->id_dev);
		return ret;
	}

	otg_dev->id = extcon_get_cable_state(extcon, "USB-HOST");
	otg_dev->vbus = extcon_get_cable_state(extcon, "USB");
	omap_otg_set_mode(otg_dev);

	rev = readl(otg_dev->base);

	dev_info(&pdev->dev,
		 "OMAP USB OTG controller rev %d.%d (%s, id=%d, vbus=%d)\n",
		 (rev >> 4) & 0xf, rev & 0xf, config->extcon, otg_dev->id,
		 otg_dev->vbus);

	return 0;
}

static int omap_otg_remove(struct platform_device *pdev)
{
	struct otg_device *otg_dev = platform_get_drvdata(pdev);

	extcon_unregister_interest(&otg_dev->id_dev);
	extcon_unregister_interest(&otg_dev->vbus_dev);

	return 0;
}

static struct platform_driver omap_otg_driver = {
	.probe		= omap_otg_probe,
	.remove		= omap_otg_remove,
	.driver		= {
		.name	= "omap_otg",
	},
};
module_platform_driver(omap_otg_driver);

MODULE_DESCRIPTION("OMAP USB OTG controller driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
