/*
 * Interrupt controller support for TWL6040
 *
 * Author:     Misael Lopez Cruz <misael.lopez@ti.com>
 *
 * Copyright:   (C) 2011 Texas Instruments, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/irqdomain.h>
#include <linux/interrupt.h>
#include <linux/mfd/core.h>
#include <linux/mfd/twl6040.h>

struct twl6040_irq_data {
	int mask;
	int status;
};

static struct twl6040_irq_data twl6040_irqs[] = {
	{
		.mask = TWL6040_THMSK,
		.status = TWL6040_THINT,
	},
	{
		.mask = TWL6040_PLUGMSK,
		.status = TWL6040_PLUGINT | TWL6040_UNPLUGINT,
	},
	{
		.mask = TWL6040_HOOKMSK,
		.status = TWL6040_HOOKINT,
	},
	{
		.mask = TWL6040_HFMSK,
		.status = TWL6040_HFINT,
	},
	{
		.mask = TWL6040_VIBMSK,
		.status = TWL6040_VIBINT,
	},
	{
		.mask = TWL6040_READYMSK,
		.status = TWL6040_READYINT,
	},
};

static inline
struct twl6040_irq_data *irq_to_twl6040_irq(struct twl6040 *twl6040,
					    int irq)
{
	return &twl6040_irqs[irq - twl6040->irq_base];
}

static void twl6040_irq_lock(struct irq_data *data)
{
	struct twl6040 *twl6040 = irq_data_get_irq_chip_data(data);

	mutex_lock(&twl6040->irq_mutex);
}

static void twl6040_irq_sync_unlock(struct irq_data *data)
{
	struct twl6040 *twl6040 = irq_data_get_irq_chip_data(data);

	/* write back to hardware any change in irq mask */
	if (twl6040->irq_masks_cur != twl6040->irq_masks_cache) {
		twl6040->irq_masks_cache = twl6040->irq_masks_cur;
		twl6040_reg_write(twl6040, TWL6040_REG_INTMR,
				  twl6040->irq_masks_cur);
	}

	mutex_unlock(&twl6040->irq_mutex);
}

static void twl6040_irq_enable(struct irq_data *data)
{
	struct twl6040 *twl6040 = irq_data_get_irq_chip_data(data);
	struct twl6040_irq_data *irq_data = irq_to_twl6040_irq(twl6040,
							       data->irq);

	twl6040->irq_masks_cur &= ~irq_data->mask;
}

static void twl6040_irq_disable(struct irq_data *data)
{
	struct twl6040 *twl6040 = irq_data_get_irq_chip_data(data);
	struct twl6040_irq_data *irq_data = irq_to_twl6040_irq(twl6040,
							       data->irq);

	twl6040->irq_masks_cur |= irq_data->mask;
}

static struct irq_chip twl6040_irq_chip = {
	.name			= "twl6040",
	.irq_bus_lock		= twl6040_irq_lock,
	.irq_bus_sync_unlock	= twl6040_irq_sync_unlock,
	.irq_enable		= twl6040_irq_enable,
	.irq_disable		= twl6040_irq_disable,
};

static irqreturn_t twl6040_irq_thread(int irq, void *data)
{
	struct twl6040 *twl6040 = data;
	u8 intid;
	int i;

	intid = twl6040_reg_read(twl6040, TWL6040_REG_INTID);

	/* apply masking and report (backwards to handle READYINT first) */
	for (i = ARRAY_SIZE(twl6040_irqs) - 1; i >= 0; i--) {
		if (twl6040->irq_masks_cur & twl6040_irqs[i].mask)
			intid &= ~twl6040_irqs[i].status;
		if (intid & twl6040_irqs[i].status)
			handle_nested_irq(twl6040->irq_base + i);
	}

	/* ack unmasked irqs */
	twl6040_reg_write(twl6040, TWL6040_REG_INTID, intid);

	return IRQ_HANDLED;
}

int twl6040_irq_init(struct twl6040 *twl6040)
{
	struct device_node *node = twl6040->dev->of_node;
	int i, nr_irqs, irq_base, ret;
	u8 val;

	mutex_init(&twl6040->irq_mutex);

	/* mask the individual interrupt sources */
	twl6040->irq_masks_cur = TWL6040_ALLINT_MSK;
	twl6040->irq_masks_cache = TWL6040_ALLINT_MSK;
	twl6040_reg_write(twl6040, TWL6040_REG_INTMR, TWL6040_ALLINT_MSK);

	nr_irqs = ARRAY_SIZE(twl6040_irqs);

	irq_base = irq_alloc_descs(-1, 0, nr_irqs, 0);
	if (IS_ERR_VALUE(irq_base)) {
		dev_err(twl6040->dev, "Fail to allocate IRQ descs\n");
		return irq_base;
	}
	twl6040->irq_base = irq_base;

	irq_domain_add_legacy(node, ARRAY_SIZE(twl6040_irqs), irq_base, 0,
			      &irq_domain_simple_ops, NULL);

	/* Register them with genirq */
	for (i = irq_base; i < irq_base + nr_irqs; i++) {
		irq_set_chip_data(i, twl6040);
		irq_set_chip_and_handler(i, &twl6040_irq_chip,
					 handle_level_irq);
		irq_set_nested_thread(i, 1);

		/* ARM needs us to explicitly flag the IRQ as valid
		 * and will set them noprobe when we do so. */
#ifdef CONFIG_ARM
		set_irq_flags(i, IRQF_VALID);
#else
		irq_set_noprobe(i);
#endif
	}

	ret = request_threaded_irq(twl6040->irq, NULL, twl6040_irq_thread,
				   IRQF_ONESHOT, "twl6040", twl6040);
	if (ret) {
		dev_err(twl6040->dev, "failed to request IRQ %d: %d\n",
			twl6040->irq, ret);
		return ret;
	}

	/* reset interrupts */
	val = twl6040_reg_read(twl6040, TWL6040_REG_INTID);

	/* interrupts cleared on write */
	twl6040_clear_bits(twl6040, TWL6040_REG_ACCCTL, TWL6040_INTCLRMODE);

	return 0;
}
EXPORT_SYMBOL(twl6040_irq_init);

void twl6040_irq_exit(struct twl6040 *twl6040)
{
	free_irq(twl6040->irq, twl6040);
}
EXPORT_SYMBOL(twl6040_irq_exit);