/*
 * MXC GPIO support. (c) 2008 Daniel Mack <daniel@caiaq.de>
 * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
 *
 * Based on code from Freescale,
 * Copyright (C) 2004-2010 Freescale Semiconductor, Inc. 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
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 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 Street, Fifth Floor, Boston,
 * MA  02110-1301, USA.
 */

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include <mach/mx23.h>
#include <mach/mx28.h>
#include <asm-generic/bug.h>

#include "gpio.h"

static struct mxs_gpio_port *mxs_gpio_ports;
static int gpio_table_size;

#define PINCTRL_DOUT(n)		((cpu_is_mx23() ? 0x0500 : 0x0700) + (n) * 0x10)
#define PINCTRL_DIN(n)		((cpu_is_mx23() ? 0x0600 : 0x0900) + (n) * 0x10)
#define PINCTRL_DOE(n)		((cpu_is_mx23() ? 0x0700 : 0x0b00) + (n) * 0x10)
#define PINCTRL_PIN2IRQ(n)	((cpu_is_mx23() ? 0x0800 : 0x1000) + (n) * 0x10)
#define PINCTRL_IRQEN(n)	((cpu_is_mx23() ? 0x0900 : 0x1100) + (n) * 0x10)
#define PINCTRL_IRQLEV(n)	((cpu_is_mx23() ? 0x0a00 : 0x1200) + (n) * 0x10)
#define PINCTRL_IRQPOL(n)	((cpu_is_mx23() ? 0x0b00 : 0x1300) + (n) * 0x10)
#define PINCTRL_IRQSTAT(n)	((cpu_is_mx23() ? 0x0c00 : 0x1400) + (n) * 0x10)

#define GPIO_INT_FALL_EDGE	0x0
#define GPIO_INT_LOW_LEV	0x1
#define GPIO_INT_RISE_EDGE	0x2
#define GPIO_INT_HIGH_LEV	0x3
#define GPIO_INT_LEV_MASK	(1 << 0)
#define GPIO_INT_POL_MASK	(1 << 1)

/* Note: This driver assumes 32 GPIOs are handled in one register */

static void clear_gpio_irqstatus(struct mxs_gpio_port *port, u32 index)
{
	__mxs_clrl(1 << index, port->base + PINCTRL_IRQSTAT(port->id));
}

static void set_gpio_irqenable(struct mxs_gpio_port *port, u32 index,
				int enable)
{
	if (enable) {
		__mxs_setl(1 << index, port->base + PINCTRL_IRQEN(port->id));
		__mxs_setl(1 << index, port->base + PINCTRL_PIN2IRQ(port->id));
	} else {
		__mxs_clrl(1 << index, port->base + PINCTRL_IRQEN(port->id));
	}
}

static void mxs_gpio_ack_irq(struct irq_data *d)
{
	u32 gpio = irq_to_gpio(d->irq);
	clear_gpio_irqstatus(&mxs_gpio_ports[gpio / 32], gpio & 0x1f);
}

static void mxs_gpio_mask_irq(struct irq_data *d)
{
	u32 gpio = irq_to_gpio(d->irq);
	set_gpio_irqenable(&mxs_gpio_ports[gpio / 32], gpio & 0x1f, 0);
}

static void mxs_gpio_unmask_irq(struct irq_data *d)
{
	u32 gpio = irq_to_gpio(d->irq);
	set_gpio_irqenable(&mxs_gpio_ports[gpio / 32], gpio & 0x1f, 1);
}

static int mxs_gpio_get(struct gpio_chip *chip, unsigned offset);

static int mxs_gpio_set_irq_type(struct irq_data *d, unsigned int type)
{
	u32 gpio = irq_to_gpio(d->irq);
	u32 pin_mask = 1 << (gpio & 31);
	struct mxs_gpio_port *port = &mxs_gpio_ports[gpio / 32];
	void __iomem *pin_addr;
	int edge;

	switch (type) {
	case IRQ_TYPE_EDGE_RISING:
		edge = GPIO_INT_RISE_EDGE;
		break;
	case IRQ_TYPE_EDGE_FALLING:
		edge = GPIO_INT_FALL_EDGE;
		break;
	case IRQ_TYPE_LEVEL_LOW:
		edge = GPIO_INT_LOW_LEV;
		break;
	case IRQ_TYPE_LEVEL_HIGH:
		edge = GPIO_INT_HIGH_LEV;
		break;
	default:
		return -EINVAL;
	}

	/* set level or edge */
	pin_addr = port->base + PINCTRL_IRQLEV(port->id);
	if (edge & GPIO_INT_LEV_MASK)
		__mxs_setl(pin_mask, pin_addr);
	else
		__mxs_clrl(pin_mask, pin_addr);

	/* set polarity */
	pin_addr = port->base + PINCTRL_IRQPOL(port->id);
	if (edge & GPIO_INT_POL_MASK)
		__mxs_setl(pin_mask, pin_addr);
	else
		__mxs_clrl(pin_mask, pin_addr);

	clear_gpio_irqstatus(port, gpio & 0x1f);

	return 0;
}

/* MXS has one interrupt *per* gpio port */
static void mxs_gpio_irq_handler(u32 irq, struct irq_desc *desc)
{
	u32 irq_stat;
	struct mxs_gpio_port *port = (struct mxs_gpio_port *)get_irq_data(irq);
	u32 gpio_irq_no_base = port->virtual_irq_start;

	desc->irq_data.chip->irq_ack(&desc->irq_data);

	irq_stat = __raw_readl(port->base + PINCTRL_IRQSTAT(port->id)) &
			__raw_readl(port->base + PINCTRL_IRQEN(port->id));

	while (irq_stat != 0) {
		int irqoffset = fls(irq_stat) - 1;
		generic_handle_irq(gpio_irq_no_base + irqoffset);
		irq_stat &= ~(1 << irqoffset);
	}
}

/*
 * Set interrupt number "irq" in the GPIO as a wake-up source.
 * While system is running, all registered GPIO interrupts need to have
 * wake-up enabled. When system is suspended, only selected GPIO interrupts
 * need to have wake-up enabled.
 * @param  irq          interrupt source number
 * @param  enable       enable as wake-up if equal to non-zero
 * @return       This function returns 0 on success.
 */
static int mxs_gpio_set_wake_irq(struct irq_data *d, unsigned int enable)
{
	u32 gpio = irq_to_gpio(d->irq);
	u32 gpio_idx = gpio & 0x1f;
	struct mxs_gpio_port *port = &mxs_gpio_ports[gpio / 32];

	if (enable) {
		if (port->irq_high && (gpio_idx >= 16))
			enable_irq_wake(port->irq_high);
		else
			enable_irq_wake(port->irq);
	} else {
		if (port->irq_high && (gpio_idx >= 16))
			disable_irq_wake(port->irq_high);
		else
			disable_irq_wake(port->irq);
	}

	return 0;
}

static struct irq_chip gpio_irq_chip = {
	.irq_ack = mxs_gpio_ack_irq,
	.irq_mask = mxs_gpio_mask_irq,
	.irq_unmask = mxs_gpio_unmask_irq,
	.irq_set_type = mxs_gpio_set_irq_type,
	.irq_set_wake = mxs_gpio_set_wake_irq,
};

static void mxs_set_gpio_direction(struct gpio_chip *chip, unsigned offset,
				int dir)
{
	struct mxs_gpio_port *port =
		container_of(chip, struct mxs_gpio_port, chip);
	void __iomem *pin_addr = port->base + PINCTRL_DOE(port->id);

	if (dir)
		__mxs_setl(1 << offset, pin_addr);
	else
		__mxs_clrl(1 << offset, pin_addr);
}

static int mxs_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct mxs_gpio_port *port =
		container_of(chip, struct mxs_gpio_port, chip);

	return (__raw_readl(port->base + PINCTRL_DIN(port->id)) >> offset) & 1;
}

static void mxs_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
	struct mxs_gpio_port *port =
		container_of(chip, struct mxs_gpio_port, chip);
	void __iomem *pin_addr = port->base + PINCTRL_DOUT(port->id);

	if (value)
		__mxs_setl(1 << offset, pin_addr);
	else
		__mxs_clrl(1 << offset, pin_addr);
}

static int mxs_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
{
	struct mxs_gpio_port *port =
		container_of(chip, struct mxs_gpio_port, chip);

	return port->virtual_irq_start + offset;
}

static int mxs_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
	mxs_set_gpio_direction(chip, offset, 0);
	return 0;
}

static int mxs_gpio_direction_output(struct gpio_chip *chip,
				     unsigned offset, int value)
{
	mxs_gpio_set(chip, offset, value);
	mxs_set_gpio_direction(chip, offset, 1);
	return 0;
}

int __init mxs_gpio_init(struct mxs_gpio_port *port, int cnt)
{
	int i, j;

	/* save for local usage */
	mxs_gpio_ports = port;
	gpio_table_size = cnt;

	pr_info("MXS GPIO hardware\n");

	for (i = 0; i < cnt; i++) {
		/* disable the interrupt and clear the status */
		__raw_writel(0, port[i].base + PINCTRL_PIN2IRQ(i));
		__raw_writel(0, port[i].base + PINCTRL_IRQEN(i));

		/* clear address has to be used to clear IRQSTAT bits */
		__mxs_clrl(~0U, port[i].base + PINCTRL_IRQSTAT(i));

		for (j = port[i].virtual_irq_start;
			j < port[i].virtual_irq_start + 32; j++) {
			set_irq_chip(j, &gpio_irq_chip);
			set_irq_handler(j, handle_level_irq);
			set_irq_flags(j, IRQF_VALID);
		}

		/* setup one handler for each entry */
		set_irq_chained_handler(port[i].irq, mxs_gpio_irq_handler);
		set_irq_data(port[i].irq, &port[i]);

		/* register gpio chip */
		port[i].chip.direction_input = mxs_gpio_direction_input;
		port[i].chip.direction_output = mxs_gpio_direction_output;
		port[i].chip.get = mxs_gpio_get;
		port[i].chip.set = mxs_gpio_set;
		port[i].chip.to_irq = mxs_gpio_to_irq;
		port[i].chip.base = i * 32;
		port[i].chip.ngpio = 32;

		/* its a serious configuration bug when it fails */
		BUG_ON(gpiochip_add(&port[i].chip) < 0);
	}

	return 0;
}

#define DEFINE_MXS_GPIO_PORT(soc, _id)					\
	{								\
		.chip.label = "gpio-" #_id,				\
		.id = _id,						\
		.irq = soc ## _INT_GPIO ## _id,				\
		.base = soc ## _IO_ADDRESS(				\
				soc ## _PINCTRL ## _BASE_ADDR),		\
		.virtual_irq_start = MXS_GPIO_IRQ_START + (_id) * 32,	\
	}

#define DEFINE_REGISTER_FUNCTION(prefix)				\
int __init prefix ## _register_gpios(void)				\
{									\
	return mxs_gpio_init(prefix ## _gpio_ports,			\
			ARRAY_SIZE(prefix ## _gpio_ports));		\
}

#ifdef CONFIG_SOC_IMX23
static struct mxs_gpio_port mx23_gpio_ports[] = {
	DEFINE_MXS_GPIO_PORT(MX23, 0),
	DEFINE_MXS_GPIO_PORT(MX23, 1),
	DEFINE_MXS_GPIO_PORT(MX23, 2),
};
DEFINE_REGISTER_FUNCTION(mx23)
#endif

#ifdef CONFIG_SOC_IMX28
static struct mxs_gpio_port mx28_gpio_ports[] = {
	DEFINE_MXS_GPIO_PORT(MX28, 0),
	DEFINE_MXS_GPIO_PORT(MX28, 1),
	DEFINE_MXS_GPIO_PORT(MX28, 2),
	DEFINE_MXS_GPIO_PORT(MX28, 3),
	DEFINE_MXS_GPIO_PORT(MX28, 4),
};
DEFINE_REGISTER_FUNCTION(mx28)
#endif