/*
 * extcon-ptn5150.c - NXP CC logic for USB Type-C applications
 *
 * Copyright 2017 NXP
 * Author: Peter Chen <peter.chen@nxp.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  of
 * the License as published by the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/extcon.h>
#include <linux/gpio/consumer.h>

/* PTN5150_REG_INT_STATUS */
#define CABLE_ATTACHED		(1 << 0)
#define CABLE_DETACHED		(1 << 1)
/* PTN5150_REG_CC_STATUS */
#define IS_DFP_ATTATCHED(val)	(((val) & 0x1c) == 0x4)
#define IS_UFP_ATTATCHED(val)	(((val) & 0x1c) == 0x8)
#define IS_NOT_CONNECTED(val)	(((val) & 0x1c) == 0x0)
/* PTN5150_REG_CON_DET */
#define DISABLE_CON_DET		(1 << 0)

struct ptn5150_info {
	struct device *dev;
	struct extcon_dev *edev;

	struct work_struct wq_detect_cable;
	struct regmap *regmap;
};

/* List of detectable cables */
static const unsigned int ptn5150_extcon_cable[] = {
	EXTCON_USB,
	EXTCON_USB_HOST,
	EXTCON_NONE,
};

enum ptn5150_reg {
	PTN5150_REG_DEVICE_ID = 0x1,
	PTN5150_REG_CONTROL,
	PTN5150_REG_INT_STATUS,
	PTN5150_REG_CC_STATUS,
	PTN5150_REG_RSVD_5,
	PTN5150_REG_RSVD_6,
	PTN5150_REG_RSVD_7,
	PTN5150_REG_RSVD_8,
	PTN5150_REG_CON_DET,
	PTN5150_REG_VCONN_STATUS,
	PTN5150_REG_RESET = 0x10,
	PTN5150_REG_RSVD_11,
	PTN5150_REG_RSVD_12,
	PTN5150_REG_RSVD_13,
	PTN5150_REG_RSVD_14,
	PTN5150_REG_RSVD_15,
	PTN5150_REG_RSVD_16,
	PTN5150_REG_RSVD_17,
	PTN5150_REG_INT_MASK,
	PTN5150_REG_INT_REG_STATUS,

	PTN5150_REG_END,
};
static const struct regmap_config ptn5150_regmap_config = {
	.reg_bits	= 8,
	.val_bits	= 8,
	.max_register	= PTN5150_REG_END,
};

static void ptn5150_detect_cable(struct work_struct *work)
{
	struct ptn5150_info *info = container_of(work, struct ptn5150_info,
			wq_detect_cable);
	int ret;
	unsigned int val;

	ret = regmap_read(info->regmap, PTN5150_REG_CC_STATUS, &val);
	if (ret)
		dev_err(info->dev, "failed to get CC status:%d\n", ret);

	if (IS_UFP_ATTATCHED(val)) {
		extcon_set_state_sync(info->edev, EXTCON_USB, false);
		extcon_set_state_sync(info->edev, EXTCON_USB_HOST,
			true);
	} else if (IS_DFP_ATTATCHED(val)) {
		extcon_set_state_sync(info->edev, EXTCON_USB_HOST,
			false);
		extcon_set_state_sync(info->edev, EXTCON_USB, true);
	} else if (IS_NOT_CONNECTED(val)) {
		extcon_set_state_sync(info->edev, EXTCON_USB, false);
		extcon_set_state_sync(info->edev, EXTCON_USB_HOST, false);
	} else {
		dev_dbg(info->dev, "other CC status is :0x%x", val);
	}
}

static int ptn5150_clear_interrupt(struct ptn5150_info *info)
{
	unsigned int val;
	int ret;

	ret = regmap_read(info->regmap, PTN5150_REG_INT_STATUS, &val);
	if (ret)
		dev_err(info->dev,
			"failed to clear interrupt status:%d\n",
			ret);

	return (ret < 0) ? ret : (int)val;
}

static irqreturn_t ptn5150_connect_irq_handler(int irq, void *dev_id)
{
	struct ptn5150_info *info = dev_id;

	if (ptn5150_clear_interrupt(info) > 0)
		queue_work(system_power_efficient_wq, &info->wq_detect_cable);

	return IRQ_HANDLED;
}

static int ptn5150_i2c_probe(struct i2c_client *i2c,
				 const struct i2c_device_id *id)
{
	struct device_node *np = i2c->dev.of_node;
	struct ptn5150_info *info;
	int ret, connect_irq, gpio_val, count = 1000;
	unsigned int dev_id;
	struct gpio_desc *connect_gpiod;

	if (!np)
		return -EINVAL;

	info = devm_kzalloc(&i2c->dev, sizeof(*info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	i2c_set_clientdata(i2c, info);
	info->dev = &i2c->dev;
	info->regmap = devm_regmap_init_i2c(i2c, &ptn5150_regmap_config);
	if (IS_ERR(info->regmap)) {
		ret = PTR_ERR(info->regmap);
		dev_err(info->dev, "failed to allocate register map: %d\n",
				   ret);
		return ret;
	}

	/* Allocate extcon device */
	info->edev = devm_extcon_dev_allocate(info->dev, ptn5150_extcon_cable);
	if (IS_ERR(info->edev)) {
		dev_err(info->dev, "failed to allocate memory for extcon\n");
		return -ENOMEM;
	}

	/* Register extcon device */
	ret = devm_extcon_dev_register(info->dev, info->edev);
	if (ret) {
		dev_err(info->dev, "failed to register extcon device\n");
		return ret;
	}

	connect_gpiod = devm_gpiod_get(info->dev, "connect", GPIOD_IN);
	if (IS_ERR(connect_gpiod)) {
		dev_err(info->dev, "failed to get connect GPIO\n");
		return PTR_ERR(connect_gpiod);
	}

	connect_irq = gpiod_to_irq(connect_gpiod);
	if (connect_irq < 0) {
		dev_err(info->dev, "failed to get connect IRQ\n");
		return connect_irq;
	}

	/* Clear the pending interrupts */
	ret = ptn5150_clear_interrupt(info);
	if (ret < 0)
		return ret;

	gpio_val = gpiod_get_value(connect_gpiod);
	/* Delay until the GPIO goes to high if it is low before */
	while (gpio_val == 0 && count >= 0) {
		gpio_val = gpiod_get_value(connect_gpiod);
		usleep_range(10, 20);
		count--;
	}

	if (count < 0)
		dev_err(info->dev, "timeout for waiting gpio becoming high\n");

	ret = regmap_read(info->regmap, PTN5150_REG_DEVICE_ID, &dev_id);
	if (ret) {
		dev_err(info->dev, "failed to read device id:%d\n", ret);
		return ret;
	}

	dev_dbg(info->dev, "NXP PTN5150: Version ID:0x%x, Vendor ID:0x%x\n",
			(dev_id >> 3), (dev_id & 0x3));

	ret = regmap_update_bits(info->regmap, PTN5150_REG_CON_DET,
			DISABLE_CON_DET, ~DISABLE_CON_DET);
	if (ret) {
		dev_err(info->dev,
			"failed to enable CON_DET output on pin 5:%d\n",
			ret);
		return ret;
	}

	INIT_WORK(&info->wq_detect_cable, ptn5150_detect_cable);

	ret = devm_request_threaded_irq(info->dev, connect_irq, NULL,
					ptn5150_connect_irq_handler,
					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
					dev_name(info->dev), info);
	if (ret < 0) {
		dev_err(info->dev, "failed to request connect IRQ\n");
		return ret;
	}

	/* Do cable detect now */
	ptn5150_detect_cable(&info->wq_detect_cable);

	return ret;
}

static int ptn5150_i2c_remove(struct i2c_client *i2c)
{
	return 0;
}

static const struct i2c_device_id ptn5150_id[] = {
	{ "ptn5150", 0 },
	{ },
};
MODULE_DEVICE_TABLE(i2c, ptn5150_id);

#ifdef CONFIG_OF
static const struct of_device_id ptn5150_of_match[] = {
	{ .compatible = "nxp,ptn5150", },
	{ .compatible = "nxp,ptn5150a", },
	{},
};
MODULE_DEVICE_TABLE(of, ptn5150_of_match);
#endif

static struct i2c_driver ptn5150_i2c_driver = {
	.driver = {
		.name = "ptn5150",
		.of_match_table = of_match_ptr(ptn5150_of_match),
	},
	.probe		= ptn5150_i2c_probe,
	.remove		= ptn5150_i2c_remove,
	.id_table	= ptn5150_id,
};
module_i2c_driver(ptn5150_i2c_driver);

MODULE_DESCRIPTION("NXP PTN5150 CC logic driver for USB Type-C");
MODULE_AUTHOR("Peter Chen <peter.chen@nxp.com>");
MODULE_LICENSE("GPL v2");