/* linux/arch/arm/mach-msm/gpio.c
 *
 * Copyright (C) 2007 Google, Inc.
 * Copyright (c) 2009-2010, Code Aurora Forum. All rights reserved.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 */

#include <linux/bitops.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/module.h>
#include "gpio_hw.h"

#define FIRST_GPIO_IRQ MSM_GPIO_TO_INT(0)

#define MSM_GPIO_BANK(bank, first, last)				\
	{								\
		.regs = {						\
			.out =         MSM_GPIO_OUT_##bank,		\
			.in =          MSM_GPIO_IN_##bank,		\
			.int_status =  MSM_GPIO_INT_STATUS_##bank,	\
			.int_clear =   MSM_GPIO_INT_CLEAR_##bank,	\
			.int_en =      MSM_GPIO_INT_EN_##bank,		\
			.int_edge =    MSM_GPIO_INT_EDGE_##bank,	\
			.int_pos =     MSM_GPIO_INT_POS_##bank,		\
			.oe =          MSM_GPIO_OE_##bank,		\
		},							\
		.chip = {						\
			.base = (first),				\
			.ngpio = (last) - (first) + 1,			\
			.get = msm_gpio_get,				\
			.set = msm_gpio_set,				\
			.direction_input = msm_gpio_direction_input,	\
			.direction_output = msm_gpio_direction_output,	\
			.to_irq = msm_gpio_to_irq,			\
		}							\
	}

#define MSM_GPIO_BROKEN_INT_CLEAR 1

struct msm_gpio_regs {
	void __iomem *out;
	void __iomem *in;
	void __iomem *int_status;
	void __iomem *int_clear;
	void __iomem *int_en;
	void __iomem *int_edge;
	void __iomem *int_pos;
	void __iomem *oe;
};

struct msm_gpio_chip {
	spinlock_t		lock;
	struct gpio_chip	chip;
	struct msm_gpio_regs	regs;
#if MSM_GPIO_BROKEN_INT_CLEAR
	unsigned                int_status_copy;
#endif
	unsigned int            both_edge_detect;
	unsigned int            int_enable[2]; /* 0: awake, 1: sleep */
};

static int msm_gpio_write(struct msm_gpio_chip *msm_chip,
			  unsigned offset, unsigned on)
{
	unsigned mask = BIT(offset);
	unsigned val;

	val = readl(msm_chip->regs.out);
	if (on)
		writel(val | mask, msm_chip->regs.out);
	else
		writel(val & ~mask, msm_chip->regs.out);
	return 0;
}

static void msm_gpio_update_both_edge_detect(struct msm_gpio_chip *msm_chip)
{
	int loop_limit = 100;
	unsigned pol, val, val2, intstat;
	do {
		val = readl(msm_chip->regs.in);
		pol = readl(msm_chip->regs.int_pos);
		pol = (pol & ~msm_chip->both_edge_detect) |
		      (~val & msm_chip->both_edge_detect);
		writel(pol, msm_chip->regs.int_pos);
		intstat = readl(msm_chip->regs.int_status);
		val2 = readl(msm_chip->regs.in);
		if (((val ^ val2) & msm_chip->both_edge_detect & ~intstat) == 0)
			return;
	} while (loop_limit-- > 0);
	printk(KERN_ERR "msm_gpio_update_both_edge_detect, "
	       "failed to reach stable state %x != %x\n", val, val2);
}

static int msm_gpio_clear_detect_status(struct msm_gpio_chip *msm_chip,
					unsigned offset)
{
	unsigned bit = BIT(offset);

#if MSM_GPIO_BROKEN_INT_CLEAR
	/* Save interrupts that already triggered before we loose them. */
	/* Any interrupt that triggers between the read of int_status */
	/* and the write to int_clear will still be lost though. */
	msm_chip->int_status_copy |= readl(msm_chip->regs.int_status);
	msm_chip->int_status_copy &= ~bit;
#endif
	writel(bit, msm_chip->regs.int_clear);
	msm_gpio_update_both_edge_detect(msm_chip);
	return 0;
}

static int msm_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
	struct msm_gpio_chip *msm_chip;
	unsigned long irq_flags;

	msm_chip = container_of(chip, struct msm_gpio_chip, chip);
	spin_lock_irqsave(&msm_chip->lock, irq_flags);
	writel(readl(msm_chip->regs.oe) & ~BIT(offset), msm_chip->regs.oe);
	spin_unlock_irqrestore(&msm_chip->lock, irq_flags);
	return 0;
}

static int
msm_gpio_direction_output(struct gpio_chip *chip, unsigned offset, int value)
{
	struct msm_gpio_chip *msm_chip;
	unsigned long irq_flags;

	msm_chip = container_of(chip, struct msm_gpio_chip, chip);
	spin_lock_irqsave(&msm_chip->lock, irq_flags);
	msm_gpio_write(msm_chip, offset, value);
	writel(readl(msm_chip->regs.oe) | BIT(offset), msm_chip->regs.oe);
	spin_unlock_irqrestore(&msm_chip->lock, irq_flags);
	return 0;
}

static int msm_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct msm_gpio_chip *msm_chip;

	msm_chip = container_of(chip, struct msm_gpio_chip, chip);
	return (readl(msm_chip->regs.in) & (1U << offset)) ? 1 : 0;
}

static void msm_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
	struct msm_gpio_chip *msm_chip;
	unsigned long irq_flags;

	msm_chip = container_of(chip, struct msm_gpio_chip, chip);
	spin_lock_irqsave(&msm_chip->lock, irq_flags);
	msm_gpio_write(msm_chip, offset, value);
	spin_unlock_irqrestore(&msm_chip->lock, irq_flags);
}

static int msm_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
{
	return MSM_GPIO_TO_INT(chip->base + offset);
}

struct msm_gpio_chip msm_gpio_chips[] = {
#if defined(CONFIG_ARCH_MSM7X00A)
	MSM_GPIO_BANK(0,   0,  15),
	MSM_GPIO_BANK(1,  16,  42),
	MSM_GPIO_BANK(2,  43,  67),
	MSM_GPIO_BANK(3,  68,  94),
	MSM_GPIO_BANK(4,  95, 106),
	MSM_GPIO_BANK(5, 107, 121),
#elif defined(CONFIG_ARCH_MSM7X25) || defined(CONFIG_ARCH_MSM7X27)
	MSM_GPIO_BANK(0,   0,  15),
	MSM_GPIO_BANK(1,  16,  42),
	MSM_GPIO_BANK(2,  43,  67),
	MSM_GPIO_BANK(3,  68,  94),
	MSM_GPIO_BANK(4,  95, 106),
	MSM_GPIO_BANK(5, 107, 132),
#elif defined(CONFIG_ARCH_MSM7X30)
	MSM_GPIO_BANK(0,   0,  15),
	MSM_GPIO_BANK(1,  16,  43),
	MSM_GPIO_BANK(2,  44,  67),
	MSM_GPIO_BANK(3,  68,  94),
	MSM_GPIO_BANK(4,  95, 106),
	MSM_GPIO_BANK(5, 107, 133),
	MSM_GPIO_BANK(6, 134, 150),
	MSM_GPIO_BANK(7, 151, 181),
#elif defined(CONFIG_ARCH_QSD8X50)
	MSM_GPIO_BANK(0,   0,  15),
	MSM_GPIO_BANK(1,  16,  42),
	MSM_GPIO_BANK(2,  43,  67),
	MSM_GPIO_BANK(3,  68,  94),
	MSM_GPIO_BANK(4,  95, 103),
	MSM_GPIO_BANK(5, 104, 121),
	MSM_GPIO_BANK(6, 122, 152),
	MSM_GPIO_BANK(7, 153, 164),
#endif
};

static void msm_gpio_irq_ack(unsigned int irq)
{
	unsigned long irq_flags;
	struct msm_gpio_chip *msm_chip = get_irq_chip_data(irq);
	spin_lock_irqsave(&msm_chip->lock, irq_flags);
	msm_gpio_clear_detect_status(msm_chip,
				     irq - gpio_to_irq(msm_chip->chip.base));
	spin_unlock_irqrestore(&msm_chip->lock, irq_flags);
}

static void msm_gpio_irq_mask(unsigned int irq)
{
	unsigned long irq_flags;
	struct msm_gpio_chip *msm_chip = get_irq_chip_data(irq);
	unsigned offset = irq - gpio_to_irq(msm_chip->chip.base);

	spin_lock_irqsave(&msm_chip->lock, irq_flags);
	/* level triggered interrupts are also latched */
	if (!(readl(msm_chip->regs.int_edge) & BIT(offset)))
		msm_gpio_clear_detect_status(msm_chip, offset);
	msm_chip->int_enable[0] &= ~BIT(offset);
	writel(msm_chip->int_enable[0], msm_chip->regs.int_en);
	spin_unlock_irqrestore(&msm_chip->lock, irq_flags);
}

static void msm_gpio_irq_unmask(unsigned int irq)
{
	unsigned long irq_flags;
	struct msm_gpio_chip *msm_chip = get_irq_chip_data(irq);
	unsigned offset = irq - gpio_to_irq(msm_chip->chip.base);

	spin_lock_irqsave(&msm_chip->lock, irq_flags);
	/* level triggered interrupts are also latched */
	if (!(readl(msm_chip->regs.int_edge) & BIT(offset)))
		msm_gpio_clear_detect_status(msm_chip, offset);
	msm_chip->int_enable[0] |= BIT(offset);
	writel(msm_chip->int_enable[0], msm_chip->regs.int_en);
	spin_unlock_irqrestore(&msm_chip->lock, irq_flags);
}

static int msm_gpio_irq_set_wake(unsigned int irq, unsigned int on)
{
	unsigned long irq_flags;
	struct msm_gpio_chip *msm_chip = get_irq_chip_data(irq);
	unsigned offset = irq - gpio_to_irq(msm_chip->chip.base);

	spin_lock_irqsave(&msm_chip->lock, irq_flags);

	if (on)
		msm_chip->int_enable[1] |= BIT(offset);
	else
		msm_chip->int_enable[1] &= ~BIT(offset);

	spin_unlock_irqrestore(&msm_chip->lock, irq_flags);
	return 0;
}

static int msm_gpio_irq_set_type(unsigned int irq, unsigned int flow_type)
{
	unsigned long irq_flags;
	struct msm_gpio_chip *msm_chip = get_irq_chip_data(irq);
	unsigned offset = irq - gpio_to_irq(msm_chip->chip.base);
	unsigned val, mask = BIT(offset);

	spin_lock_irqsave(&msm_chip->lock, irq_flags);
	val = readl(msm_chip->regs.int_edge);
	if (flow_type & IRQ_TYPE_EDGE_BOTH) {
		writel(val | mask, msm_chip->regs.int_edge);
		irq_desc[irq].handle_irq = handle_edge_irq;
	} else {
		writel(val & ~mask, msm_chip->regs.int_edge);
		irq_desc[irq].handle_irq = handle_level_irq;
	}
	if ((flow_type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH) {
		msm_chip->both_edge_detect |= mask;
		msm_gpio_update_both_edge_detect(msm_chip);
	} else {
		msm_chip->both_edge_detect &= ~mask;
		val = readl(msm_chip->regs.int_pos);
		if (flow_type & (IRQF_TRIGGER_RISING | IRQF_TRIGGER_HIGH))
			writel(val | mask, msm_chip->regs.int_pos);
		else
			writel(val & ~mask, msm_chip->regs.int_pos);
	}
	spin_unlock_irqrestore(&msm_chip->lock, irq_flags);
	return 0;
}

static void msm_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
{
	int i, j, mask;
	unsigned val;

	for (i = 0; i < ARRAY_SIZE(msm_gpio_chips); i++) {
		struct msm_gpio_chip *msm_chip = &msm_gpio_chips[i];
		val = readl(msm_chip->regs.int_status);
		val &= msm_chip->int_enable[0];
		while (val) {
			mask = val & -val;
			j = fls(mask) - 1;
			/* printk("%s %08x %08x bit %d gpio %d irq %d\n",
				__func__, v, m, j, msm_chip->chip.start + j,
				FIRST_GPIO_IRQ + msm_chip->chip.start + j); */
			val &= ~mask;
			generic_handle_irq(FIRST_GPIO_IRQ +
					   msm_chip->chip.base + j);
		}
	}
	desc->chip->ack(irq);
}

static struct irq_chip msm_gpio_irq_chip = {
	.name      = "msmgpio",
	.ack       = msm_gpio_irq_ack,
	.mask      = msm_gpio_irq_mask,
	.unmask    = msm_gpio_irq_unmask,
	.set_wake  = msm_gpio_irq_set_wake,
	.set_type  = msm_gpio_irq_set_type,
};

static int __init msm_init_gpio(void)
{
	int i, j = 0;

	for (i = FIRST_GPIO_IRQ; i < FIRST_GPIO_IRQ + NR_GPIO_IRQS; i++) {
		if (i - FIRST_GPIO_IRQ >=
			msm_gpio_chips[j].chip.base +
			msm_gpio_chips[j].chip.ngpio)
			j++;
		set_irq_chip_data(i, &msm_gpio_chips[j]);
		set_irq_chip(i, &msm_gpio_irq_chip);
		set_irq_handler(i, handle_edge_irq);
		set_irq_flags(i, IRQF_VALID);
	}

	for (i = 0; i < ARRAY_SIZE(msm_gpio_chips); i++) {
		spin_lock_init(&msm_gpio_chips[i].lock);
		writel(0, msm_gpio_chips[i].regs.int_en);
		gpiochip_add(&msm_gpio_chips[i].chip);
	}

	set_irq_chained_handler(INT_GPIO_GROUP1, msm_gpio_irq_handler);
	set_irq_chained_handler(INT_GPIO_GROUP2, msm_gpio_irq_handler);
	set_irq_wake(INT_GPIO_GROUP1, 1);
	set_irq_wake(INT_GPIO_GROUP2, 2);
	return 0;
}

postcore_initcall(msm_init_gpio);