/*
 * linux/arch/arm/mach-sa1100/gpio.c
 *
 * Generic SA-1100 GPIO handling
 *
 * 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.
 */
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/syscore_ops.h>
#include <soc/sa1100/pwer.h>
#include <mach/hardware.h>
#include <mach/irqs.h>

struct sa1100_gpio_chip {
        struct gpio_chip chip;
        void __iomem *membase;
        int irqbase;
        u32 irqmask;
        u32 irqrising;
        u32 irqfalling;
        u32 irqwake;
};

#define sa1100_gpio_chip(x) container_of(x, struct sa1100_gpio_chip, chip)

enum {
        R_GPLR = 0x00,
        R_GPDR = 0x04,
        R_GPSR = 0x08,
        R_GPCR = 0x0c,
        R_GRER = 0x10,
        R_GFER = 0x14,
        R_GEDR = 0x18,
        R_GAFR = 0x1c,
};

static int sa1100_gpio_get(struct gpio_chip *chip, unsigned offset)
{
        return readl_relaxed(sa1100_gpio_chip(chip)->membase + R_GPLR) &
                BIT(offset);
}

static void sa1100_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
        int reg = value ? R_GPSR : R_GPCR;

        writel_relaxed(BIT(offset), sa1100_gpio_chip(chip)->membase + reg);
}

static int sa1100_get_direction(struct gpio_chip *chip, unsigned offset)
{
        void __iomem *gpdr = sa1100_gpio_chip(chip)->membase + R_GPDR;

        return !(readl_relaxed(gpdr) & BIT(offset));
}

static int sa1100_direction_input(struct gpio_chip *chip, unsigned offset)
{
        void __iomem *gpdr = sa1100_gpio_chip(chip)->membase + R_GPDR;
        unsigned long flags;

        local_irq_save(flags);
        writel_relaxed(readl_relaxed(gpdr) & ~BIT(offset), gpdr);
        local_irq_restore(flags);

        return 0;
}

static int sa1100_direction_output(struct gpio_chip *chip, unsigned offset, int value)
{
        void __iomem *gpdr = sa1100_gpio_chip(chip)->membase + R_GPDR;
        unsigned long flags;

        local_irq_save(flags);
        sa1100_gpio_set(chip, offset, value);
        writel_relaxed(readl_relaxed(gpdr) | BIT(offset), gpdr);
        local_irq_restore(flags);

        return 0;
}

static int sa1100_to_irq(struct gpio_chip *chip, unsigned offset)
{
        return sa1100_gpio_chip(chip)->irqbase + offset;
}

static struct sa1100_gpio_chip sa1100_gpio_chip = {
        .chip = {
                .label                  = "gpio",
                .get_direction          = sa1100_get_direction,
                .direction_input        = sa1100_direction_input,
                .direction_output       = sa1100_direction_output,
                .set                    = sa1100_gpio_set,
                .get                    = sa1100_gpio_get,
                .to_irq                 = sa1100_to_irq,
                .base                   = 0,
                .ngpio                  = GPIO_MAX + 1,
        },
        .membase = (void *)&GPLR,
        .irqbase = IRQ_GPIO0,
};

/*
 * SA1100 GPIO edge detection for IRQs:
 * IRQs are generated on Falling-Edge, Rising-Edge, or both.
 * Use this instead of directly setting GRER/GFER.
 */
static void sa1100_update_edge_regs(struct sa1100_gpio_chip *sgc)
{
        void *base = sgc->membase;
        u32 grer, gfer;

        grer = sgc->irqrising & sgc->irqmask;
        gfer = sgc->irqfalling & sgc->irqmask;

        writel_relaxed(grer, base + R_GRER);
        writel_relaxed(gfer, base + R_GFER);
}

static int sa1100_gpio_type(struct irq_data *d, unsigned int type)
{
        struct sa1100_gpio_chip *sgc = irq_data_get_irq_chip_data(d);
        unsigned int mask = BIT(d->hwirq);

        if (type == IRQ_TYPE_PROBE) {
                if ((sgc->irqrising | sgc->irqfalling) & mask)
                        return 0;
                type = IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING;
        }

        if (type & IRQ_TYPE_EDGE_RISING)
                sgc->irqrising |= mask;
        else
                sgc->irqrising &= ~mask;
        if (type & IRQ_TYPE_EDGE_FALLING)
                sgc->irqfalling |= mask;
        else
                sgc->irqfalling &= ~mask;

        sa1100_update_edge_regs(sgc);

        return 0;
}

/*
 * GPIO IRQs must be acknowledged.
 */
static void sa1100_gpio_ack(struct irq_data *d)
{
        struct sa1100_gpio_chip *sgc = irq_data_get_irq_chip_data(d);

        writel_relaxed(BIT(d->hwirq), sgc->membase + R_GEDR);
}

static void sa1100_gpio_mask(struct irq_data *d)
{
        struct sa1100_gpio_chip *sgc = irq_data_get_irq_chip_data(d);
        unsigned int mask = BIT(d->hwirq);

        sgc->irqmask &= ~mask;

        sa1100_update_edge_regs(sgc);
}

static void sa1100_gpio_unmask(struct irq_data *d)
{
        struct sa1100_gpio_chip *sgc = irq_data_get_irq_chip_data(d);
        unsigned int mask = BIT(d->hwirq);

        sgc->irqmask |= mask;

        sa1100_update_edge_regs(sgc);
}

static int sa1100_gpio_wake(struct irq_data *d, unsigned int on)
{
        struct sa1100_gpio_chip *sgc = irq_data_get_irq_chip_data(d);
        int ret = sa11x0_gpio_set_wake(d->hwirq, on);
        if (!ret) {
                if (on)
                        sgc->irqwake |= BIT(d->hwirq);
                else
                        sgc->irqwake &= ~BIT(d->hwirq);
        }
        return ret;
}

/*
 * This is for GPIO IRQs
 */
static struct irq_chip sa1100_gpio_irq_chip = {
        .name           = "GPIO",
        .irq_ack        = sa1100_gpio_ack,
        .irq_mask       = sa1100_gpio_mask,
        .irq_unmask     = sa1100_gpio_unmask,
        .irq_set_type   = sa1100_gpio_type,
        .irq_set_wake   = sa1100_gpio_wake,
};

static int sa1100_gpio_irqdomain_map(struct irq_domain *d,
                unsigned int irq, irq_hw_number_t hwirq)
{
        struct sa1100_gpio_chip *sgc = d->host_data;

        irq_set_chip_data(irq, sgc);
        irq_set_chip_and_handler(irq, &sa1100_gpio_irq_chip, handle_edge_irq);
        irq_set_probe(irq);

        return 0;
}

static const struct irq_domain_ops sa1100_gpio_irqdomain_ops = {
        .map = sa1100_gpio_irqdomain_map,
        .xlate = irq_domain_xlate_onetwocell,
};

static struct irq_domain *sa1100_gpio_irqdomain;

/*
 * IRQ 0-11 (GPIO) handler.  We enter here with the
 * irq_controller_lock held, and IRQs disabled.  Decode the IRQ
 * and call the handler.
 */
static void sa1100_gpio_handler(struct irq_desc *desc)
{
        struct sa1100_gpio_chip *sgc = irq_desc_get_handler_data(desc);
        unsigned int irq, mask;
        void __iomem *gedr = sgc->membase + R_GEDR;

        mask = readl_relaxed(gedr);
        do {
                /*
                 * clear down all currently active IRQ sources.
                 * We will be processing them all.
                 */
                writel_relaxed(mask, gedr);

                irq = sgc->irqbase;
                do {
                        if (mask & 1)
                                generic_handle_irq(irq);
                        mask >>= 1;
                        irq++;
                } while (mask);

                mask = readl_relaxed(gedr);
        } while (mask);
}

static int sa1100_gpio_suspend(void)
{
        struct sa1100_gpio_chip *sgc = &sa1100_gpio_chip;

        /*
         * Set the appropriate edges for wakeup.
         */
        writel_relaxed(sgc->irqwake & sgc->irqrising, sgc->membase + R_GRER);
        writel_relaxed(sgc->irqwake & sgc->irqfalling, sgc->membase + R_GFER);

        /*
         * Clear any pending GPIO interrupts.
         */
        writel_relaxed(readl_relaxed(sgc->membase + R_GEDR),
                       sgc->membase + R_GEDR);

        return 0;
}

static void sa1100_gpio_resume(void)
{
        sa1100_update_edge_regs(&sa1100_gpio_chip);
}

static struct syscore_ops sa1100_gpio_syscore_ops = {
        .suspend        = sa1100_gpio_suspend,
        .resume         = sa1100_gpio_resume,
};

static int __init sa1100_gpio_init_devicefs(void)
{
        register_syscore_ops(&sa1100_gpio_syscore_ops);
        return 0;
}

device_initcall(sa1100_gpio_init_devicefs);

static const int sa1100_gpio_irqs[] __initconst = {
        /* Install handlers for GPIO 0-10 edge detect interrupts */
        IRQ_GPIO0_SC,
        IRQ_GPIO1_SC,
        IRQ_GPIO2_SC,
        IRQ_GPIO3_SC,
        IRQ_GPIO4_SC,
        IRQ_GPIO5_SC,
        IRQ_GPIO6_SC,
        IRQ_GPIO7_SC,
        IRQ_GPIO8_SC,
        IRQ_GPIO9_SC,
        IRQ_GPIO10_SC,
        /* Install handler for GPIO 11-27 edge detect interrupts */
        IRQ_GPIO11_27,
};

void __init sa1100_init_gpio(void)
{
        struct sa1100_gpio_chip *sgc = &sa1100_gpio_chip;
        int i;

        /* clear all GPIO edge detects */
        writel_relaxed(0, sgc->membase + R_GFER);
        writel_relaxed(0, sgc->membase + R_GRER);
        writel_relaxed(-1, sgc->membase + R_GEDR);

        gpiochip_add_data(&sa1100_gpio_chip.chip, NULL);

        sa1100_gpio_irqdomain = irq_domain_add_simple(NULL,
                        28, IRQ_GPIO0,
                        &sa1100_gpio_irqdomain_ops, sgc);

        for (i = 0; i < ARRAY_SIZE(sa1100_gpio_irqs); i++)
                irq_set_chained_handler_and_data(sa1100_gpio_irqs[i],
                                                 sa1100_gpio_handler, sgc);
}