/* Copyright (c) 2011-2013, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 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.
 */

#define pr_fmt(fmt)	"%s: " fmt, __func__

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/mfd/pm8xxx/core.h>
#include <linux/mfd/pm8xxx/gpio.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

/* GPIO registers */
#define	SSBI_REG_ADDR_GPIO_BASE		0x150
#define	SSBI_REG_ADDR_GPIO(n)		(SSBI_REG_ADDR_GPIO_BASE + n)

/* GPIO */
#define	PM_GPIO_BANK_MASK		0x70
#define	PM_GPIO_BANK_SHIFT		4
#define	PM_GPIO_WRITE			0x80

/* Bank 0 */
#define	PM_GPIO_VIN_MASK		0x0E
#define	PM_GPIO_VIN_SHIFT		1
#define	PM_GPIO_MODE_ENABLE		0x01

/* Bank 1 */
#define	PM_GPIO_MODE_MASK		0x0C
#define	PM_GPIO_MODE_SHIFT		2
#define	PM_GPIO_OUT_BUFFER		0x02
#define	PM_GPIO_OUT_INVERT		0x01

#define	PM_GPIO_MODE_OFF		3
#define	PM_GPIO_MODE_OUTPUT		2
#define	PM_GPIO_MODE_INPUT		0
#define	PM_GPIO_MODE_BOTH		1

/* Bank 2 */
#define	PM_GPIO_PULL_MASK		0x0E
#define	PM_GPIO_PULL_SHIFT		1

/* Bank 3 */
#define	PM_GPIO_OUT_STRENGTH_MASK	0x0C
#define	PM_GPIO_OUT_STRENGTH_SHIFT	2
#define PM_GPIO_PIN_ENABLE		0x00
#define	PM_GPIO_PIN_DISABLE		0x01

/* Bank 4 */
#define	PM_GPIO_FUNC_MASK		0x0E
#define	PM_GPIO_FUNC_SHIFT		1

/* Bank 5 */
#define	PM_GPIO_NON_INT_POL_INV	0x08
#define PM_GPIO_BANKS		6

struct pm_gpio_chip {
	struct list_head	link;
	struct gpio_chip	gpio_chip;
	spinlock_t		pm_lock;
	u8			*bank1;
	int			irq_base;
};

static LIST_HEAD(pm_gpio_chips);
static DEFINE_MUTEX(pm_gpio_chips_lock);

static int pm_gpio_get(struct pm_gpio_chip *pm_gpio_chip, unsigned gpio)
{
	int	mode;

	/* Get gpio value from config bank 1 if output gpio.
	   Get gpio value from IRQ RT status register for all other gpio modes.
	 */
	mode = (pm_gpio_chip->bank1[gpio] & PM_GPIO_MODE_MASK) >>
		PM_GPIO_MODE_SHIFT;
	if (mode == PM_GPIO_MODE_OUTPUT)
		return pm_gpio_chip->bank1[gpio] & PM_GPIO_OUT_INVERT;
	else
		return pm8xxx_read_irq_stat(pm_gpio_chip->gpio_chip.dev->parent,
				pm_gpio_chip->irq_base + gpio);
}

static int pm_gpio_set(struct pm_gpio_chip *pm_gpio_chip,
		unsigned gpio, int value)
{
	int	rc;
	u8	bank1;
	unsigned long flags;

	spin_lock_irqsave(&pm_gpio_chip->pm_lock, flags);
	bank1 = PM_GPIO_WRITE
			| (pm_gpio_chip->bank1[gpio] & ~PM_GPIO_OUT_INVERT);

	if (value)
		bank1 |= PM_GPIO_OUT_INVERT;

	pm_gpio_chip->bank1[gpio] = bank1;
	rc = pm8xxx_writeb(pm_gpio_chip->gpio_chip.dev->parent,
				SSBI_REG_ADDR_GPIO(gpio), bank1);
	spin_unlock_irqrestore(&pm_gpio_chip->pm_lock, flags);

	if (rc)
		pr_err("FAIL pm8xxx_writeb(): rc=%d. "
		       "(gpio=%d, value=%d)\n",
		       rc, gpio, value);

	return rc;
}

static int dir_map[] = {
	PM_GPIO_MODE_OFF,
	PM_GPIO_MODE_OUTPUT,
	PM_GPIO_MODE_INPUT,
	PM_GPIO_MODE_BOTH,
};

static int pm_gpio_set_direction(struct pm_gpio_chip *pm_gpio_chip,
			      unsigned gpio, int direction)
{
	int	rc;
	u8	bank1;
	unsigned long flags;

	if (!direction || pm_gpio_chip == NULL)
		return -EINVAL;

	spin_lock_irqsave(&pm_gpio_chip->pm_lock, flags);
	bank1 = PM_GPIO_WRITE
			| (pm_gpio_chip->bank1[gpio] & ~PM_GPIO_MODE_MASK);

	bank1 |= ((dir_map[direction] << PM_GPIO_MODE_SHIFT)
		  & PM_GPIO_MODE_MASK);

	pm_gpio_chip->bank1[gpio] = bank1;
	rc = pm8xxx_writeb(pm_gpio_chip->gpio_chip.dev->parent,
				SSBI_REG_ADDR_GPIO(gpio), bank1);
	spin_unlock_irqrestore(&pm_gpio_chip->pm_lock, flags);

	if (rc)
		pr_err("Failed on pm8xxx_writeb(): rc=%d (GPIO config)\n",
			rc);

	return rc;
}

static int pm_gpio_init_bank1(struct pm_gpio_chip *pm_gpio_chip)
{
	int i, rc;
	u8 bank;

	for (i = 0; i < pm_gpio_chip->gpio_chip.ngpio; i++) {
		bank = 1 << PM_GPIO_BANK_SHIFT;
		rc = pm8xxx_writeb(pm_gpio_chip->gpio_chip.dev->parent,
				SSBI_REG_ADDR_GPIO(i),
				bank);
		if (rc) {
			pr_err("error setting bank rc=%d\n", rc);
			return rc;
		}

		rc = pm8xxx_readb(pm_gpio_chip->gpio_chip.dev->parent,
				SSBI_REG_ADDR_GPIO(i),
				&pm_gpio_chip->bank1[i]);
		if (rc) {
			pr_err("error reading bank 1 rc=%d\n", rc);
			return rc;
		}
	}
	return 0;
}

static int pm_gpio_to_irq(struct gpio_chip *gpio_chip, unsigned offset)
{
	struct pm_gpio_chip *pm_gpio_chip = dev_get_drvdata(gpio_chip->dev);

	return pm_gpio_chip->irq_base + offset;
}

static int pm_gpio_read(struct gpio_chip *gpio_chip, unsigned offset)
{
	struct pm_gpio_chip *pm_gpio_chip = dev_get_drvdata(gpio_chip->dev);

	return pm_gpio_get(pm_gpio_chip, offset);
}

static void pm_gpio_write(struct gpio_chip *gpio_chip,
		unsigned offset, int val)
{
	struct pm_gpio_chip *pm_gpio_chip = dev_get_drvdata(gpio_chip->dev);

	pm_gpio_set(pm_gpio_chip, offset, val);
}

static int pm_gpio_direction_input(struct gpio_chip *gpio_chip,
		unsigned offset)
{
	struct pm_gpio_chip *pm_gpio_chip = dev_get_drvdata(gpio_chip->dev);

	return pm_gpio_set_direction(pm_gpio_chip, offset, PM_GPIO_DIR_IN);
}

static int pm_gpio_direction_output(struct gpio_chip *gpio_chip,
		unsigned offset,
		int val)
{
	int ret;
	struct pm_gpio_chip *pm_gpio_chip = dev_get_drvdata(gpio_chip->dev);

	ret = pm_gpio_set_direction(pm_gpio_chip, offset, PM_GPIO_DIR_OUT);
	if (!ret)
		ret = pm_gpio_set(pm_gpio_chip, offset, val);

	return ret;
}

static void pm_gpio_dbg_show(struct seq_file *s, struct gpio_chip *gpio_chip)
{
	static const char * const cmode[] = { "in", "in/out", "out", "off" };
	struct pm_gpio_chip *pm_gpio_chip = dev_get_drvdata(gpio_chip->dev);
	u8 mode, state, bank;
	const char *label;
	int i, j;

	for (i = 0; i < gpio_chip->ngpio; i++) {
		label = gpiochip_is_requested(gpio_chip, i);
		mode = (pm_gpio_chip->bank1[i] & PM_GPIO_MODE_MASK) >>
			PM_GPIO_MODE_SHIFT;
		state = pm_gpio_get(pm_gpio_chip, i);
		seq_printf(s, "gpio-%-3d (%-12.12s) %-10.10s"
				" %s",
				gpio_chip->base + i,
				label ? label : "--",
				cmode[mode],
				state ? "hi" : "lo");
		for (j = 0; j < PM_GPIO_BANKS; j++) {
			bank = j << PM_GPIO_BANK_SHIFT;
			pm8xxx_writeb(gpio_chip->dev->parent,
					SSBI_REG_ADDR_GPIO(i),
					bank);
			pm8xxx_readb(gpio_chip->dev->parent,
					SSBI_REG_ADDR_GPIO(i),
					&bank);
			seq_printf(s, " 0x%02x", bank);
		}
		seq_printf(s, "\n");
	}
}

static int pm_gpio_probe(struct platform_device *pdev)
{
	int ret;
	const struct pm8xxx_gpio_platform_data *pdata = pdev->dev.platform_data;
	struct pm_gpio_chip *pm_gpio_chip;

	if (!pdata) {
		pr_err("missing platform data\n");
		return -EINVAL;
	}

	pm_gpio_chip = kzalloc(sizeof(struct pm_gpio_chip), GFP_KERNEL);
	if (!pm_gpio_chip) {
		pr_err("Cannot allocate pm_gpio_chip\n");
		return -ENOMEM;
	}

	pm_gpio_chip->bank1 = kzalloc(sizeof(u8) * pdata->gpio_cdata.ngpios,
					GFP_KERNEL);
	if (!pm_gpio_chip->bank1) {
		pr_err("Cannot allocate pm_gpio_chip->bank1\n");
		ret = -ENOMEM;
		goto free_chip;
	}

	spin_lock_init(&pm_gpio_chip->pm_lock);
	pm_gpio_chip->gpio_chip.label = "pm-gpio";
	pm_gpio_chip->gpio_chip.direction_input	= pm_gpio_direction_input;
	pm_gpio_chip->gpio_chip.direction_output = pm_gpio_direction_output;
	pm_gpio_chip->gpio_chip.to_irq = pm_gpio_to_irq;
	pm_gpio_chip->gpio_chip.get = pm_gpio_read;
	pm_gpio_chip->gpio_chip.set = pm_gpio_write;
	pm_gpio_chip->gpio_chip.dbg_show = pm_gpio_dbg_show;
	pm_gpio_chip->gpio_chip.ngpio = pdata->gpio_cdata.ngpios;
	pm_gpio_chip->gpio_chip.can_sleep = 0;
	pm_gpio_chip->gpio_chip.dev = &pdev->dev;
	pm_gpio_chip->gpio_chip.base = pdata->gpio_base;
	pm_gpio_chip->irq_base = platform_get_irq(pdev, 0);
	mutex_lock(&pm_gpio_chips_lock);
	list_add(&pm_gpio_chip->link, &pm_gpio_chips);
	mutex_unlock(&pm_gpio_chips_lock);
	platform_set_drvdata(pdev, pm_gpio_chip);

	ret = gpiochip_add(&pm_gpio_chip->gpio_chip);
	if (ret) {
		pr_err("gpiochip_add failed ret = %d\n", ret);
		goto reset_drvdata;
	}

	ret = pm_gpio_init_bank1(pm_gpio_chip);
	if (ret) {
		pr_err("gpio init bank failed ret = %d\n", ret);
		goto remove_chip;
	}

	pr_info("OK: base=%d, ngpio=%d\n", pm_gpio_chip->gpio_chip.base,
		pm_gpio_chip->gpio_chip.ngpio);

	return 0;

remove_chip:
	if (gpiochip_remove(&pm_gpio_chip->gpio_chip))
		pr_err("failed to remove gpio chip\n");
reset_drvdata:
	platform_set_drvdata(pdev, NULL);
	kfree(pm_gpio_chip->bank1);
free_chip:
	kfree(pm_gpio_chip);
	return ret;
}

static int pm_gpio_remove(struct platform_device *pdev)
{
	struct pm_gpio_chip *pm_gpio_chip
		= platform_get_drvdata(pdev);

	mutex_lock(&pm_gpio_chips_lock);
	list_del(&pm_gpio_chip->link);
	mutex_unlock(&pm_gpio_chips_lock);
	platform_set_drvdata(pdev, NULL);
	if (gpiochip_remove(&pm_gpio_chip->gpio_chip))
		pr_err("failed to remove gpio chip\n");
	kfree(pm_gpio_chip->bank1);
	kfree(pm_gpio_chip);
	return 0;
}

int pm8xxx_gpio_config(int gpio, struct pm_gpio *param)
{
	int	rc, pm_gpio = -EINVAL;
	u8	bank[8];
	unsigned long flags;
	struct pm_gpio_chip *pm_gpio_chip;
	struct gpio_chip *gpio_chip;

	if (param == NULL)
		return -EINVAL;

	mutex_lock(&pm_gpio_chips_lock);
	list_for_each_entry(pm_gpio_chip, &pm_gpio_chips, link) {
		gpio_chip = &pm_gpio_chip->gpio_chip;
		if (gpio >= gpio_chip->base
			&& gpio < gpio_chip->base + gpio_chip->ngpio) {
			pm_gpio = gpio - gpio_chip->base;
			break;
		}
	}
	mutex_unlock(&pm_gpio_chips_lock);
	if (pm_gpio < 0) {
		pr_err("called on gpio %d not handled by any pmic\n", gpio);
		return -EINVAL;
	}

	/* Select banks and configure the gpio */
	bank[0] = PM_GPIO_WRITE |
		((param->vin_sel << PM_GPIO_VIN_SHIFT) &
			PM_GPIO_VIN_MASK) |
		PM_GPIO_MODE_ENABLE;
	bank[1] = PM_GPIO_WRITE |
		((1 << PM_GPIO_BANK_SHIFT) &
			PM_GPIO_BANK_MASK) |
		((dir_map[param->direction] <<
			PM_GPIO_MODE_SHIFT) &
			PM_GPIO_MODE_MASK) |
		((param->direction & PM_GPIO_DIR_OUT) ?
			((param->output_buffer & 1) ?
			 PM_GPIO_OUT_BUFFER : 0) : 0) |
		((param->direction & PM_GPIO_DIR_OUT) ?
			param->output_value & 0x01 : 0);
	bank[2] = PM_GPIO_WRITE |
		((2 << PM_GPIO_BANK_SHIFT) &
			PM_GPIO_BANK_MASK) |
		((param->pull << PM_GPIO_PULL_SHIFT) &
			PM_GPIO_PULL_MASK);
	bank[3] = PM_GPIO_WRITE |
		((3 << PM_GPIO_BANK_SHIFT) &
			PM_GPIO_BANK_MASK) |
		((param->out_strength <<
			PM_GPIO_OUT_STRENGTH_SHIFT) &
			PM_GPIO_OUT_STRENGTH_MASK) |
		(param->disable_pin ?
			PM_GPIO_PIN_DISABLE : PM_GPIO_PIN_ENABLE);
	bank[4] = PM_GPIO_WRITE |
		((4 << PM_GPIO_BANK_SHIFT) &
			PM_GPIO_BANK_MASK) |
		((param->function << PM_GPIO_FUNC_SHIFT) &
			PM_GPIO_FUNC_MASK);
	bank[5] = PM_GPIO_WRITE |
		((5 << PM_GPIO_BANK_SHIFT) & PM_GPIO_BANK_MASK) |
		(param->inv_int_pol ? 0 : PM_GPIO_NON_INT_POL_INV);

	spin_lock_irqsave(&pm_gpio_chip->pm_lock, flags);
	/* Remember bank1 for later use */
	pm_gpio_chip->bank1[pm_gpio] = bank[1];
	rc = pm8xxx_write_buf(pm_gpio_chip->gpio_chip.dev->parent,
			SSBI_REG_ADDR_GPIO(pm_gpio), bank, 6);
	spin_unlock_irqrestore(&pm_gpio_chip->pm_lock, flags);

	if (rc)
		pr_err("Failed on pm8xxx_write_buf() rc=%d (GPIO config)\n",
			rc);

	return rc;
}
EXPORT_SYMBOL(pm8xxx_gpio_config);

static struct platform_driver pm_gpio_driver = {
	.probe		= pm_gpio_probe,
	.remove		= pm_gpio_remove,
	.driver		= {
		.name	= PM8XXX_GPIO_DEV_NAME,
		.owner	= THIS_MODULE,
	},
};

static int __init pm_gpio_init(void)
{
	return platform_driver_register(&pm_gpio_driver);
}
postcore_initcall(pm_gpio_init);

static void __exit pm_gpio_exit(void)
{
	platform_driver_unregister(&pm_gpio_driver);
}
module_exit(pm_gpio_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("PMIC GPIO driver");
MODULE_VERSION("1.0");
MODULE_ALIAS("platform:" PM8XXX_GPIO_DEV_NAME);