/*
 * TI TPS6586x GPIO driver
 *
 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
 * Author: Laxman dewangan <ldewangan@nvidia.com>
 *
 * Based on tps6586x.c
 * Copyright (c) 2010 CompuLab Ltd.
 * Mike Rapoport <mike@compulab.co.il>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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/errno.h>
#include <linux/gpio.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mfd/tps6586x.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>

/* GPIO control registers */
#define TPS6586X_GPIOSET1	0x5d
#define TPS6586X_GPIOSET2	0x5e

struct tps6586x_gpio {
	struct gpio_chip gpio_chip;
	struct device *parent;
};

static inline struct tps6586x_gpio *to_tps6586x_gpio(struct gpio_chip *chip)
{
	return container_of(chip, struct tps6586x_gpio, gpio_chip);
}

static int tps6586x_gpio_get(struct gpio_chip *gc, unsigned offset)
{
	struct tps6586x_gpio *tps6586x_gpio = to_tps6586x_gpio(gc);
	uint8_t val;
	int ret;

	ret = tps6586x_read(tps6586x_gpio->parent, TPS6586X_GPIOSET2, &val);
	if (ret)
		return ret;

	return !!(val & (1 << offset));
}

static void tps6586x_gpio_set(struct gpio_chip *gc, unsigned offset,
			      int value)
{
	struct tps6586x_gpio *tps6586x_gpio = to_tps6586x_gpio(gc);

	tps6586x_update(tps6586x_gpio->parent, TPS6586X_GPIOSET2,
			value << offset, 1 << offset);
}

static int tps6586x_gpio_input(struct gpio_chip *gc, unsigned offset)
{
	/* FIXME: add handling of GPIOs as dedicated inputs */
	return -ENOSYS;
}

static int tps6586x_gpio_output(struct gpio_chip *gc, unsigned offset,
				int value)
{
	struct tps6586x_gpio *tps6586x_gpio = to_tps6586x_gpio(gc);
	uint8_t val, mask;
	int ret;

	val = value << offset;
	mask = 0x1 << offset;
	ret = tps6586x_update(tps6586x_gpio->parent, TPS6586X_GPIOSET2,
				val, mask);

	val = 0x1 << (offset * 2);
	mask = 0x3 << (offset * 2);

	return tps6586x_update(tps6586x_gpio->parent, TPS6586X_GPIOSET1,
				val, mask);
}

static int tps6586x_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
{
	struct tps6586x_gpio *tps6586x_gpio = to_tps6586x_gpio(gc);

	return tps6586x_irq_get_virq(tps6586x_gpio->parent,
				TPS6586X_INT_PLDO_0 + offset);
}

static int tps6586x_gpio_probe(struct platform_device *pdev)
{
	struct tps6586x_platform_data *pdata;
	struct tps6586x_gpio *tps6586x_gpio;
	int ret;

	pdata = dev_get_platdata(pdev->dev.parent);
	tps6586x_gpio = devm_kzalloc(&pdev->dev,
				sizeof(*tps6586x_gpio), GFP_KERNEL);
	if (!tps6586x_gpio) {
		dev_err(&pdev->dev, "Could not allocate tps6586x_gpio\n");
		return -ENOMEM;
	}

	tps6586x_gpio->parent = pdev->dev.parent;

	tps6586x_gpio->gpio_chip.owner = THIS_MODULE;
	tps6586x_gpio->gpio_chip.label = pdev->name;
	tps6586x_gpio->gpio_chip.dev = &pdev->dev;
	tps6586x_gpio->gpio_chip.ngpio = 4;
	tps6586x_gpio->gpio_chip.can_sleep = 1;

	tps6586x_gpio->gpio_chip.direction_input = tps6586x_gpio_input;
	tps6586x_gpio->gpio_chip.direction_output = tps6586x_gpio_output;
	tps6586x_gpio->gpio_chip.set	= tps6586x_gpio_set;
	tps6586x_gpio->gpio_chip.get	= tps6586x_gpio_get;
	tps6586x_gpio->gpio_chip.to_irq	= tps6586x_gpio_to_irq;

#ifdef CONFIG_OF_GPIO
	tps6586x_gpio->gpio_chip.of_node = pdev->dev.parent->of_node;
#endif
	if (pdata && pdata->gpio_base)
		tps6586x_gpio->gpio_chip.base = pdata->gpio_base;
	else
		tps6586x_gpio->gpio_chip.base = -1;

	ret = gpiochip_add(&tps6586x_gpio->gpio_chip);
	if (ret < 0) {
		dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
		return ret;
	}

	platform_set_drvdata(pdev, tps6586x_gpio);

	return ret;
}

static int tps6586x_gpio_remove(struct platform_device *pdev)
{
	struct tps6586x_gpio *tps6586x_gpio = platform_get_drvdata(pdev);

	return gpiochip_remove(&tps6586x_gpio->gpio_chip);
}

static struct platform_driver tps6586x_gpio_driver = {
	.driver.name	= "tps6586x-gpio",
	.driver.owner	= THIS_MODULE,
	.probe		= tps6586x_gpio_probe,
	.remove		= tps6586x_gpio_remove,
};

static int __init tps6586x_gpio_init(void)
{
	return platform_driver_register(&tps6586x_gpio_driver);
}
subsys_initcall(tps6586x_gpio_init);

static void __exit tps6586x_gpio_exit(void)
{
	platform_driver_unregister(&tps6586x_gpio_driver);
}
module_exit(tps6586x_gpio_exit);

MODULE_ALIAS("platform:tps6586x-gpio");
MODULE_DESCRIPTION("GPIO interface for TPS6586X PMIC");
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_LICENSE("GPL");