/*
 * TI DaVinci GPIO Support
 *
 * Copyright (c) 2006-2007 David Brownell
 * Copyright (c) 2007, MontaVista Software, Inc. <source@mvista.com>
 *
 * 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.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/bitops.h>

#include <mach/cputype.h>
#include <mach/irqs.h>
#include <mach/hardware.h>
#include <mach/common.h>
#include <mach/gpio.h>

#include <asm/mach/irq.h>


static DEFINE_SPINLOCK(gpio_lock);

struct davinci_gpio {
	struct gpio_chip	chip;
	struct gpio_controller	*__iomem regs;
};

static struct davinci_gpio chips[DIV_ROUND_UP(DAVINCI_N_GPIO, 32)];

/* create a non-inlined version */
static struct gpio_controller __iomem * __init gpio2controller(unsigned gpio)
{
	return __gpio_to_controller(gpio);
}

static int __init davinci_gpio_irq_setup(void);

/*--------------------------------------------------------------------------*/

/*
 * board setup code *MUST* set PINMUX0 and PINMUX1 as
 * needed, and enable the GPIO clock.
 */

static int davinci_direction_in(struct gpio_chip *chip, unsigned offset)
{
	struct davinci_gpio *d = container_of(chip, struct davinci_gpio, chip);
	struct gpio_controller *__iomem g = d->regs;
	u32 temp;

	spin_lock(&gpio_lock);
	temp = __raw_readl(&g->dir);
	temp |= (1 << offset);
	__raw_writel(temp, &g->dir);
	spin_unlock(&gpio_lock);

	return 0;
}

/*
 * Read the pin's value (works even if it's set up as output);
 * returns zero/nonzero.
 *
 * Note that changes are synched to the GPIO clock, so reading values back
 * right after you've set them may give old values.
 */
static int davinci_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct davinci_gpio *d = container_of(chip, struct davinci_gpio, chip);
	struct gpio_controller *__iomem g = d->regs;

	return (1 << offset) & __raw_readl(&g->in_data);
}

static int
davinci_direction_out(struct gpio_chip *chip, unsigned offset, int value)
{
	struct davinci_gpio *d = container_of(chip, struct davinci_gpio, chip);
	struct gpio_controller *__iomem g = d->regs;
	u32 temp;
	u32 mask = 1 << offset;

	spin_lock(&gpio_lock);
	temp = __raw_readl(&g->dir);
	temp &= ~mask;
	__raw_writel(mask, value ? &g->set_data : &g->clr_data);
	__raw_writel(temp, &g->dir);
	spin_unlock(&gpio_lock);
	return 0;
}

/*
 * Assuming the pin is muxed as a gpio output, set its output value.
 */
static void
davinci_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
	struct davinci_gpio *d = container_of(chip, struct davinci_gpio, chip);
	struct gpio_controller *__iomem g = d->regs;

	__raw_writel((1 << offset), value ? &g->set_data : &g->clr_data);
}

static int __init davinci_gpio_setup(void)
{
	int i, base;
	unsigned ngpio;
	struct davinci_soc_info *soc_info = &davinci_soc_info;

	/*
	 * The gpio banks conceptually expose a segmented bitmap,
	 * and "ngpio" is one more than the largest zero-based
	 * bit index that's valid.
	 */
	ngpio = soc_info->gpio_num;
	if (ngpio == 0) {
		pr_err("GPIO setup:  how many GPIOs?\n");
		return -EINVAL;
	}

	if (WARN_ON(DAVINCI_N_GPIO < ngpio))
		ngpio = DAVINCI_N_GPIO;

	for (i = 0, base = 0; base < ngpio; i++, base += 32) {
		chips[i].chip.label = "DaVinci";

		chips[i].chip.direction_input = davinci_direction_in;
		chips[i].chip.get = davinci_gpio_get;
		chips[i].chip.direction_output = davinci_direction_out;
		chips[i].chip.set = davinci_gpio_set;

		chips[i].chip.base = base;
		chips[i].chip.ngpio = ngpio - base;
		if (chips[i].chip.ngpio > 32)
			chips[i].chip.ngpio = 32;

		chips[i].regs = gpio2controller(base);

		gpiochip_add(&chips[i].chip);
	}

	davinci_gpio_irq_setup();
	return 0;
}
pure_initcall(davinci_gpio_setup);

/*--------------------------------------------------------------------------*/
/*
 * We expect irqs will normally be set up as input pins, but they can also be
 * used as output pins ... which is convenient for testing.
 *
 * NOTE:  The first few GPIOs also have direct INTC hookups in addition
 * to their GPIOBNK0 irq, with a bit less overhead but less flexibility
 * on triggering (e.g. no edge options).  We don't try to use those.
 *
 * All those INTC hookups (direct, plus several IRQ banks) can also
 * serve as EDMA event triggers.
 */

static void gpio_irq_disable(unsigned irq)
{
	struct gpio_controller *__iomem g = get_irq_chip_data(irq);
	u32 mask = __gpio_mask(irq_to_gpio(irq));

	__raw_writel(mask, &g->clr_falling);
	__raw_writel(mask, &g->clr_rising);
}

static void gpio_irq_enable(unsigned irq)
{
	struct gpio_controller *__iomem g = get_irq_chip_data(irq);
	u32 mask = __gpio_mask(irq_to_gpio(irq));
	unsigned status = irq_desc[irq].status;

	status &= IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;
	if (!status)
		status = IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;

	if (status & IRQ_TYPE_EDGE_FALLING)
		__raw_writel(mask, &g->set_falling);
	if (status & IRQ_TYPE_EDGE_RISING)
		__raw_writel(mask, &g->set_rising);
}

static int gpio_irq_type(unsigned irq, unsigned trigger)
{
	struct gpio_controller *__iomem g = get_irq_chip_data(irq);
	u32 mask = __gpio_mask(irq_to_gpio(irq));

	if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
		return -EINVAL;

	irq_desc[irq].status &= ~IRQ_TYPE_SENSE_MASK;
	irq_desc[irq].status |= trigger;

	/* don't enable the IRQ if it's currently disabled */
	if (irq_desc[irq].depth == 0) {
		__raw_writel(mask, (trigger & IRQ_TYPE_EDGE_FALLING)
			     ? &g->set_falling : &g->clr_falling);
		__raw_writel(mask, (trigger & IRQ_TYPE_EDGE_RISING)
			     ? &g->set_rising : &g->clr_rising);
	}
	return 0;
}

static struct irq_chip gpio_irqchip = {
	.name		= "GPIO",
	.enable		= gpio_irq_enable,
	.disable	= gpio_irq_disable,
	.set_type	= gpio_irq_type,
};

static void
gpio_irq_handler(unsigned irq, struct irq_desc *desc)
{
	struct gpio_controller *__iomem g = get_irq_chip_data(irq);
	u32 mask = 0xffff;

	/* we only care about one bank */
	if (irq & 1)
		mask <<= 16;

	/* temporarily mask (level sensitive) parent IRQ */
	desc->chip->mask(irq);
	desc->chip->ack(irq);
	while (1) {
		u32		status;
		int		n;
		int		res;

		/* ack any irqs */
		status = __raw_readl(&g->intstat) & mask;
		if (!status)
			break;
		__raw_writel(status, &g->intstat);
		if (irq & 1)
			status >>= 16;

		/* now demux them to the right lowlevel handler */
		n = (int)get_irq_data(irq);
		while (status) {
			res = ffs(status);
			n += res;
			generic_handle_irq(n - 1);
			status >>= res;
		}
	}
	desc->chip->unmask(irq);
	/* now it may re-trigger */
}

/*
 * NOTE:  for suspend/resume, probably best to make a platform_device with
 * suspend_late/resume_resume calls hooking into results of the set_wake()
 * calls ... so if no gpios are wakeup events the clock can be disabled,
 * with outputs left at previously set levels, and so that VDD3P3V.IOPWDN0
 * (dm6446) can be set appropriately for GPIOV33 pins.
 */

static int __init davinci_gpio_irq_setup(void)
{
	unsigned	gpio, irq, bank;
	struct clk	*clk;
	u32		binten = 0;
	unsigned	ngpio, bank_irq;
	struct davinci_soc_info *soc_info = &davinci_soc_info;

	ngpio = soc_info->gpio_num;

	bank_irq = soc_info->gpio_irq;
	if (bank_irq == 0) {
		printk(KERN_ERR "Don't know first GPIO bank IRQ.\n");
		return -EINVAL;
	}

	clk = clk_get(NULL, "gpio");
	if (IS_ERR(clk)) {
		printk(KERN_ERR "Error %ld getting gpio clock?\n",
		       PTR_ERR(clk));
		return PTR_ERR(clk);
	}
	clk_enable(clk);

	for (gpio = 0, irq = gpio_to_irq(0), bank = 0;
			gpio < ngpio;
			bank++, bank_irq++) {
		struct gpio_controller	*__iomem g = gpio2controller(gpio);
		unsigned		i;

		__raw_writel(~0, &g->clr_falling);
		__raw_writel(~0, &g->clr_rising);

		/* set up all irqs in this bank */
		set_irq_chained_handler(bank_irq, gpio_irq_handler);
		set_irq_chip_data(bank_irq, g);
		set_irq_data(bank_irq, (void *)irq);

		for (i = 0; i < 16 && gpio < ngpio; i++, irq++, gpio++) {
			set_irq_chip(irq, &gpio_irqchip);
			set_irq_chip_data(irq, g);
			set_irq_handler(irq, handle_simple_irq);
			set_irq_flags(irq, IRQF_VALID);
		}

		binten |= BIT(bank);
	}

	/* BINTEN -- per-bank interrupt enable. genirq would also let these
	 * bits be set/cleared dynamically.
	 */
	__raw_writel(binten, soc_info->gpio_base + 0x08);

	printk(KERN_INFO "DaVinci: %d gpio irqs\n", irq - gpio_to_irq(0));

	return 0;
}