/*
 * Copyright (C) ST-Ericsson SA 2010
 *
 * License Terms: GNU General Public License, version 2
 * Author: Hanumath Prasad <hanumath.prasad@stericsson.com> for ST-Ericsson
 * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/of.h>
#include <linux/mfd/core.h>
#include <linux/mfd/tc3589x.h>

/**
 * enum tc3589x_version - indicates the TC3589x version
 */
enum tc3589x_version {
	TC3589X_TC35890,
	TC3589X_TC35892,
	TC3589X_TC35893,
	TC3589X_TC35894,
	TC3589X_TC35895,
	TC3589X_TC35896,
	TC3589X_UNKNOWN,
};

#define TC3589x_CLKMODE_MODCTL_SLEEP		0x0
#define TC3589x_CLKMODE_MODCTL_OPERATION	(1 << 0)

/**
 * tc3589x_reg_read() - read a single TC3589x register
 * @tc3589x:	Device to read from
 * @reg:	Register to read
 */
int tc3589x_reg_read(struct tc3589x *tc3589x, u8 reg)
{
	int ret;

	ret = i2c_smbus_read_byte_data(tc3589x->i2c, reg);
	if (ret < 0)
		dev_err(tc3589x->dev, "failed to read reg %#x: %d\n",
			reg, ret);

	return ret;
}
EXPORT_SYMBOL_GPL(tc3589x_reg_read);

/**
 * tc3589x_reg_read() - write a single TC3589x register
 * @tc3589x:	Device to write to
 * @reg:	Register to read
 * @data:	Value to write
 */
int tc3589x_reg_write(struct tc3589x *tc3589x, u8 reg, u8 data)
{
	int ret;

	ret = i2c_smbus_write_byte_data(tc3589x->i2c, reg, data);
	if (ret < 0)
		dev_err(tc3589x->dev, "failed to write reg %#x: %d\n",
			reg, ret);

	return ret;
}
EXPORT_SYMBOL_GPL(tc3589x_reg_write);

/**
 * tc3589x_block_read() - read multiple TC3589x registers
 * @tc3589x:	Device to read from
 * @reg:	First register
 * @length:	Number of registers
 * @values:	Buffer to write to
 */
int tc3589x_block_read(struct tc3589x *tc3589x, u8 reg, u8 length, u8 *values)
{
	int ret;

	ret = i2c_smbus_read_i2c_block_data(tc3589x->i2c, reg, length, values);
	if (ret < 0)
		dev_err(tc3589x->dev, "failed to read regs %#x: %d\n",
			reg, ret);

	return ret;
}
EXPORT_SYMBOL_GPL(tc3589x_block_read);

/**
 * tc3589x_block_write() - write multiple TC3589x registers
 * @tc3589x:	Device to write to
 * @reg:	First register
 * @length:	Number of registers
 * @values:	Values to write
 */
int tc3589x_block_write(struct tc3589x *tc3589x, u8 reg, u8 length,
			const u8 *values)
{
	int ret;

	ret = i2c_smbus_write_i2c_block_data(tc3589x->i2c, reg, length,
					     values);
	if (ret < 0)
		dev_err(tc3589x->dev, "failed to write regs %#x: %d\n",
			reg, ret);

	return ret;
}
EXPORT_SYMBOL_GPL(tc3589x_block_write);

/**
 * tc3589x_set_bits() - set the value of a bitfield in a TC3589x register
 * @tc3589x:	Device to write to
 * @reg:	Register to write
 * @mask:	Mask of bits to set
 * @values:	Value to set
 */
int tc3589x_set_bits(struct tc3589x *tc3589x, u8 reg, u8 mask, u8 val)
{
	int ret;

	mutex_lock(&tc3589x->lock);

	ret = tc3589x_reg_read(tc3589x, reg);
	if (ret < 0)
		goto out;

	ret &= ~mask;
	ret |= val;

	ret = tc3589x_reg_write(tc3589x, reg, ret);

out:
	mutex_unlock(&tc3589x->lock);
	return ret;
}
EXPORT_SYMBOL_GPL(tc3589x_set_bits);

static struct resource gpio_resources[] = {
	{
		.start	= TC3589x_INT_GPIIRQ,
		.end	= TC3589x_INT_GPIIRQ,
		.flags	= IORESOURCE_IRQ,
	},
};

static struct resource keypad_resources[] = {
	{
		.start  = TC3589x_INT_KBDIRQ,
		.end    = TC3589x_INT_KBDIRQ,
		.flags  = IORESOURCE_IRQ,
	},
};

static const struct mfd_cell tc3589x_dev_gpio[] = {
	{
		.name		= "tc3589x-gpio",
		.num_resources	= ARRAY_SIZE(gpio_resources),
		.resources	= &gpio_resources[0],
		.of_compatible	= "tc3589x-gpio",
	},
};

static const struct mfd_cell tc3589x_dev_keypad[] = {
	{
		.name           = "tc3589x-keypad",
		.num_resources  = ARRAY_SIZE(keypad_resources),
		.resources      = &keypad_resources[0],
		.of_compatible	= "tc3589x-keypad",
	},
};

static irqreturn_t tc3589x_irq(int irq, void *data)
{
	struct tc3589x *tc3589x = data;
	int status;

again:
	status = tc3589x_reg_read(tc3589x, TC3589x_IRQST);
	if (status < 0)
		return IRQ_NONE;

	while (status) {
		int bit = __ffs(status);
		int virq = irq_create_mapping(tc3589x->domain, bit);

		handle_nested_irq(virq);
		status &= ~(1 << bit);
	}

	/*
	 * A dummy read or write (to any register) appears to be necessary to
	 * have the last interrupt clear (for example, GPIO IC write) take
	 * effect. In such a case, recheck for any interrupt which is still
	 * pending.
	 */
	status = tc3589x_reg_read(tc3589x, TC3589x_IRQST);
	if (status)
		goto again;

	return IRQ_HANDLED;
}

static int tc3589x_irq_map(struct irq_domain *d, unsigned int virq,
				irq_hw_number_t hwirq)
{
	struct tc3589x *tc3589x = d->host_data;

	irq_set_chip_data(virq, tc3589x);
	irq_set_chip_and_handler(virq, &dummy_irq_chip,
				handle_edge_irq);
	irq_set_nested_thread(virq, 1);
#ifdef CONFIG_ARM
	set_irq_flags(virq, IRQF_VALID);
#else
	irq_set_noprobe(virq);
#endif

	return 0;
}

static void tc3589x_irq_unmap(struct irq_domain *d, unsigned int virq)
{
#ifdef CONFIG_ARM
	set_irq_flags(virq, 0);
#endif
	irq_set_chip_and_handler(virq, NULL, NULL);
	irq_set_chip_data(virq, NULL);
}

static struct irq_domain_ops tc3589x_irq_ops = {
	.map    = tc3589x_irq_map,
	.unmap  = tc3589x_irq_unmap,
	.xlate  = irq_domain_xlate_twocell,
};

static int tc3589x_irq_init(struct tc3589x *tc3589x, struct device_node *np)
{
	int base = tc3589x->irq_base;

	tc3589x->domain = irq_domain_add_simple(
		np, TC3589x_NR_INTERNAL_IRQS, base,
		&tc3589x_irq_ops, tc3589x);

	if (!tc3589x->domain) {
		dev_err(tc3589x->dev, "Failed to create irqdomain\n");
		return -ENOSYS;
	}

	return 0;
}

static int tc3589x_chip_init(struct tc3589x *tc3589x)
{
	int manf, ver, ret;

	manf = tc3589x_reg_read(tc3589x, TC3589x_MANFCODE);
	if (manf < 0)
		return manf;

	ver = tc3589x_reg_read(tc3589x, TC3589x_VERSION);
	if (ver < 0)
		return ver;

	if (manf != TC3589x_MANFCODE_MAGIC) {
		dev_err(tc3589x->dev, "unknown manufacturer: %#x\n", manf);
		return -EINVAL;
	}

	dev_info(tc3589x->dev, "manufacturer: %#x, version: %#x\n", manf, ver);

	/*
	 * Put everything except the IRQ module into reset;
	 * also spare the GPIO module for any pin initialization
	 * done during pre-kernel boot
	 */
	ret = tc3589x_reg_write(tc3589x, TC3589x_RSTCTRL,
				TC3589x_RSTCTRL_TIMRST
				| TC3589x_RSTCTRL_ROTRST
				| TC3589x_RSTCTRL_KBDRST);
	if (ret < 0)
		return ret;

	/* Clear the reset interrupt. */
	return tc3589x_reg_write(tc3589x, TC3589x_RSTINTCLR, 0x1);
}

static int tc3589x_device_init(struct tc3589x *tc3589x)
{
	int ret = 0;
	unsigned int blocks = tc3589x->pdata->block;

	if (blocks & TC3589x_BLOCK_GPIO) {
		ret = mfd_add_devices(tc3589x->dev, -1, tc3589x_dev_gpio,
				      ARRAY_SIZE(tc3589x_dev_gpio), NULL,
				      tc3589x->irq_base, tc3589x->domain);
		if (ret) {
			dev_err(tc3589x->dev, "failed to add gpio child\n");
			return ret;
		}
		dev_info(tc3589x->dev, "added gpio block\n");
	}

	if (blocks & TC3589x_BLOCK_KEYPAD) {
		ret = mfd_add_devices(tc3589x->dev, -1, tc3589x_dev_keypad,
				      ARRAY_SIZE(tc3589x_dev_keypad), NULL,
				      tc3589x->irq_base, tc3589x->domain);
		if (ret) {
			dev_err(tc3589x->dev, "failed to keypad child\n");
			return ret;
		}
		dev_info(tc3589x->dev, "added keypad block\n");
	}

	return ret;
}

static int tc3589x_of_probe(struct device_node *np,
			struct tc3589x_platform_data *pdata)
{
	struct device_node *child;

	for_each_child_of_node(np, child) {
		if (!strcmp(child->name, "tc3589x_gpio")) {
			pdata->block |= TC3589x_BLOCK_GPIO;
		}
		if (!strcmp(child->name, "tc3589x_keypad")) {
			pdata->block |= TC3589x_BLOCK_KEYPAD;
		}
	}

	return 0;
}

static int tc3589x_probe(struct i2c_client *i2c,
				   const struct i2c_device_id *id)
{
	struct tc3589x_platform_data *pdata = dev_get_platdata(&i2c->dev);
	struct device_node *np = i2c->dev.of_node;
	struct tc3589x *tc3589x;
	int ret;

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

			ret = tc3589x_of_probe(np, pdata);
			if (ret)
				return ret;
		}
		else {
			dev_err(&i2c->dev, "No platform data or DT found\n");
			return -EINVAL;
		}
	}

	if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA
				     | I2C_FUNC_SMBUS_I2C_BLOCK))
		return -EIO;

	tc3589x = devm_kzalloc(&i2c->dev, sizeof(struct tc3589x),
				GFP_KERNEL);
	if (!tc3589x)
		return -ENOMEM;

	mutex_init(&tc3589x->lock);

	tc3589x->dev = &i2c->dev;
	tc3589x->i2c = i2c;
	tc3589x->pdata = pdata;
	tc3589x->irq_base = pdata->irq_base;

	switch (id->driver_data) {
	case TC3589X_TC35893:
	case TC3589X_TC35895:
	case TC3589X_TC35896:
		tc3589x->num_gpio = 20;
		break;
	case TC3589X_TC35890:
	case TC3589X_TC35892:
	case TC3589X_TC35894:
	case TC3589X_UNKNOWN:
	default:
		tc3589x->num_gpio = 24;
		break;
	}

	i2c_set_clientdata(i2c, tc3589x);

	ret = tc3589x_chip_init(tc3589x);
	if (ret)
		return ret;

	ret = tc3589x_irq_init(tc3589x, np);
	if (ret)
		return ret;

	ret = request_threaded_irq(tc3589x->i2c->irq, NULL, tc3589x_irq,
				   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
				   "tc3589x", tc3589x);
	if (ret) {
		dev_err(tc3589x->dev, "failed to request IRQ: %d\n", ret);
		return ret;
	}

	ret = tc3589x_device_init(tc3589x);
	if (ret) {
		dev_err(tc3589x->dev, "failed to add child devices\n");
		return ret;
	}

	return 0;
}

static int tc3589x_remove(struct i2c_client *client)
{
	struct tc3589x *tc3589x = i2c_get_clientdata(client);

	mfd_remove_devices(tc3589x->dev);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int tc3589x_suspend(struct device *dev)
{
	struct tc3589x *tc3589x = dev_get_drvdata(dev);
	struct i2c_client *client = tc3589x->i2c;
	int ret = 0;

	/* put the system to sleep mode */
	if (!device_may_wakeup(&client->dev))
		ret = tc3589x_reg_write(tc3589x, TC3589x_CLKMODE,
				TC3589x_CLKMODE_MODCTL_SLEEP);

	return ret;
}

static int tc3589x_resume(struct device *dev)
{
	struct tc3589x *tc3589x = dev_get_drvdata(dev);
	struct i2c_client *client = tc3589x->i2c;
	int ret = 0;

	/* enable the system into operation */
	if (!device_may_wakeup(&client->dev))
		ret = tc3589x_reg_write(tc3589x, TC3589x_CLKMODE,
				TC3589x_CLKMODE_MODCTL_OPERATION);

	return ret;
}
#endif

static SIMPLE_DEV_PM_OPS(tc3589x_dev_pm_ops, tc3589x_suspend, tc3589x_resume);

static const struct i2c_device_id tc3589x_id[] = {
	{ "tc35890", TC3589X_TC35890 },
	{ "tc35892", TC3589X_TC35892 },
	{ "tc35893", TC3589X_TC35893 },
	{ "tc35894", TC3589X_TC35894 },
	{ "tc35895", TC3589X_TC35895 },
	{ "tc35896", TC3589X_TC35896 },
	{ "tc3589x", TC3589X_UNKNOWN },
	{ }
};
MODULE_DEVICE_TABLE(i2c, tc3589x_id);

static struct i2c_driver tc3589x_driver = {
	.driver.name	= "tc3589x",
	.driver.owner	= THIS_MODULE,
	.driver.pm	= &tc3589x_dev_pm_ops,
	.probe		= tc3589x_probe,
	.remove		= tc3589x_remove,
	.id_table	= tc3589x_id,
};

static int __init tc3589x_init(void)
{
	return i2c_add_driver(&tc3589x_driver);
}
subsys_initcall(tc3589x_init);

static void __exit tc3589x_exit(void)
{
	i2c_del_driver(&tc3589x_driver);
}
module_exit(tc3589x_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("TC3589x MFD core driver");
MODULE_AUTHOR("Hanumath Prasad, Rabin Vincent");