/*
 * linux/arch/arm/mach-at91/gpio.c
 *
 * Copyright (C) 2005 HP Labs
 *
 * 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/clk.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <mach/at91_pio.h>
#include <mach/gpio.h>

#include <asm/gpio.h>

#include "generic.h"

struct at91_gpio_chip {
        struct gpio_chip        chip;
        struct at91_gpio_chip   *next;          /* Bank sharing same clock */
        struct at91_gpio_bank   *bank;          /* Bank definition */
        void __iomem            *regbase;       /* Base of register bank */
};

#define to_at91_gpio_chip(c) container_of(c, struct at91_gpio_chip, chip)

static void at91_gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip);
static void at91_gpiolib_set(struct gpio_chip *chip, unsigned offset, int val);
static int at91_gpiolib_get(struct gpio_chip *chip, unsigned offset);
static int at91_gpiolib_direction_output(struct gpio_chip *chip,
                                         unsigned offset, int val);
static int at91_gpiolib_direction_input(struct gpio_chip *chip,
                                        unsigned offset);

#define AT91_GPIO_CHIP(name, base_gpio, nr_gpio)                        \
        {                                                               \
                .chip = {                                               \
                        .label            = name,                       \
                        .direction_input  = at91_gpiolib_direction_input, \
                        .direction_output = at91_gpiolib_direction_output, \
                        .get              = at91_gpiolib_get,           \
                        .set              = at91_gpiolib_set,           \
                        .dbg_show         = at91_gpiolib_dbg_show,      \
                        .base             = base_gpio,                  \
                        .ngpio            = nr_gpio,                    \
                },                                                      \
        }

static struct at91_gpio_chip gpio_chip[] = {
        AT91_GPIO_CHIP("A", 0x00 + PIN_BASE, 32),
        AT91_GPIO_CHIP("B", 0x20 + PIN_BASE, 32),
        AT91_GPIO_CHIP("C", 0x40 + PIN_BASE, 32),
        AT91_GPIO_CHIP("D", 0x60 + PIN_BASE, 32),
        AT91_GPIO_CHIP("E", 0x80 + PIN_BASE, 32),
};

static int gpio_banks;

static inline void __iomem *pin_to_controller(unsigned pin)
{
        pin -= PIN_BASE;
        pin /= 32;
        if (likely(pin < gpio_banks))
                return gpio_chip[pin].regbase;

        return NULL;
}

static inline unsigned pin_to_mask(unsigned pin)
{
        pin -= PIN_BASE;
        return 1 << (pin % 32);
}


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

/* Not all hardware capabilities are exposed through these calls; they
 * only encapsulate the most common features and modes.  (So if you
 * want to change signals in groups, do it directly.)
 *
 * Bootloaders will usually handle some of the pin multiplexing setup.
 * The intent is certainly that by the time Linux is fully booted, all
 * pins should have been fully initialized.  These setup calls should
 * only be used by board setup routines, or possibly in driver probe().
 *
 * For bootloaders doing all that setup, these calls could be inlined
 * as NOPs so Linux won't duplicate any setup code
 */


/*
 * mux the pin to the "GPIO" peripheral role.
 */
int __init_or_module at91_set_GPIO_periph(unsigned pin, int use_pullup)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (!pio)
                return -EINVAL;
        __raw_writel(mask, pio + PIO_IDR);
        __raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
        __raw_writel(mask, pio + PIO_PER);
        return 0;
}
EXPORT_SYMBOL(at91_set_GPIO_periph);


/*
 * mux the pin to the "A" internal peripheral role.
 */
int __init_or_module at91_set_A_periph(unsigned pin, int use_pullup)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (!pio)
                return -EINVAL;

        __raw_writel(mask, pio + PIO_IDR);
        __raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
        __raw_writel(mask, pio + PIO_ASR);
        __raw_writel(mask, pio + PIO_PDR);
        return 0;
}
EXPORT_SYMBOL(at91_set_A_periph);


/*
 * mux the pin to the "B" internal peripheral role.
 */
int __init_or_module at91_set_B_periph(unsigned pin, int use_pullup)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (!pio)
                return -EINVAL;

        __raw_writel(mask, pio + PIO_IDR);
        __raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
        __raw_writel(mask, pio + PIO_BSR);
        __raw_writel(mask, pio + PIO_PDR);
        return 0;
}
EXPORT_SYMBOL(at91_set_B_periph);


/*
 * mux the pin to the gpio controller (instead of "A" or "B" peripheral), and
 * configure it for an input.
 */
int __init_or_module at91_set_gpio_input(unsigned pin, int use_pullup)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (!pio)
                return -EINVAL;

        __raw_writel(mask, pio + PIO_IDR);
        __raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
        __raw_writel(mask, pio + PIO_ODR);
        __raw_writel(mask, pio + PIO_PER);
        return 0;
}
EXPORT_SYMBOL(at91_set_gpio_input);


/*
 * mux the pin to the gpio controller (instead of "A" or "B" peripheral),
 * and configure it for an output.
 */
int __init_or_module at91_set_gpio_output(unsigned pin, int value)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (!pio)
                return -EINVAL;

        __raw_writel(mask, pio + PIO_IDR);
        __raw_writel(mask, pio + PIO_PUDR);
        __raw_writel(mask, pio + (value ? PIO_SODR : PIO_CODR));
        __raw_writel(mask, pio + PIO_OER);
        __raw_writel(mask, pio + PIO_PER);
        return 0;
}
EXPORT_SYMBOL(at91_set_gpio_output);


/*
 * enable/disable the glitch filter; mostly used with IRQ handling.
 */
int __init_or_module at91_set_deglitch(unsigned pin, int is_on)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (!pio)
                return -EINVAL;
        __raw_writel(mask, pio + (is_on ? PIO_IFER : PIO_IFDR));
        return 0;
}
EXPORT_SYMBOL(at91_set_deglitch);

/*
 * enable/disable the multi-driver; This is only valid for output and
 * allows the output pin to run as an open collector output.
 */
int __init_or_module at91_set_multi_drive(unsigned pin, int is_on)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (!pio)
                return -EINVAL;

        __raw_writel(mask, pio + (is_on ? PIO_MDER : PIO_MDDR));
        return 0;
}
EXPORT_SYMBOL(at91_set_multi_drive);

/*
 * assuming the pin is muxed as a gpio output, set its value.
 */
int at91_set_gpio_value(unsigned pin, int value)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (!pio)
                return -EINVAL;
        __raw_writel(mask, pio + (value ? PIO_SODR : PIO_CODR));
        return 0;
}
EXPORT_SYMBOL(at91_set_gpio_value);


/*
 * read the pin's value (works even if it's not muxed as a gpio).
 */
int at91_get_gpio_value(unsigned pin)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);
        u32             pdsr;

        if (!pio)
                return -EINVAL;
        pdsr = __raw_readl(pio + PIO_PDSR);
        return (pdsr & mask) != 0;
}
EXPORT_SYMBOL(at91_get_gpio_value);

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

#ifdef CONFIG_PM

static u32 wakeups[MAX_GPIO_BANKS];
static u32 backups[MAX_GPIO_BANKS];

static int gpio_irq_set_wake(unsigned pin, unsigned state)
{
        unsigned        mask = pin_to_mask(pin);
        unsigned        bank = (pin - PIN_BASE) / 32;

        if (unlikely(bank >= MAX_GPIO_BANKS))
                return -EINVAL;

        if (state)
                wakeups[bank] |= mask;
        else
                wakeups[bank] &= ~mask;

        set_irq_wake(gpio_chip[bank].bank->id, state);

        return 0;
}

void at91_gpio_suspend(void)
{
        int i;

        for (i = 0; i < gpio_banks; i++) {
                void __iomem    *pio = gpio_chip[i].regbase;

                backups[i] = __raw_readl(pio + PIO_IMR);
                __raw_writel(backups[i], pio + PIO_IDR);
                __raw_writel(wakeups[i], pio + PIO_IER);

                if (!wakeups[i])
                        clk_disable(gpio_chip[i].bank->clock);
                else {
#ifdef CONFIG_PM_DEBUG
                        printk(KERN_DEBUG "GPIO-%c may wake for %08x\n", 'A'+i, wakeups[i]);
#endif
                }
        }
}

void at91_gpio_resume(void)
{
        int i;

        for (i = 0; i < gpio_banks; i++) {
                void __iomem    *pio = gpio_chip[i].regbase;

                if (!wakeups[i])
                        clk_enable(gpio_chip[i].bank->clock);

                __raw_writel(wakeups[i], pio + PIO_IDR);
                __raw_writel(backups[i], pio + PIO_IER);
        }
}

#else
#define gpio_irq_set_wake       NULL
#endif


/* Several AIC controller irqs are dispatched through this GPIO handler.
 * To use any AT91_PIN_* as an externally triggered IRQ, first call
 * at91_set_gpio_input() then maybe enable its glitch filter.
 * Then just request_irq() with the pin ID; it works like any ARM IRQ
 * handler, though it always triggers on rising and falling edges.
 *
 * Alternatively, certain pins may be used directly as IRQ0..IRQ6 after
 * configuring them with at91_set_a_periph() or at91_set_b_periph().
 * IRQ0..IRQ6 should be configurable, e.g. level vs edge triggering.
 */

static void gpio_irq_mask(unsigned pin)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (pio)
                __raw_writel(mask, pio + PIO_IDR);
}

static void gpio_irq_unmask(unsigned pin)
{
        void __iomem    *pio = pin_to_controller(pin);
        unsigned        mask = pin_to_mask(pin);

        if (pio)
                __raw_writel(mask, pio + PIO_IER);
}

static int gpio_irq_type(unsigned pin, unsigned type)
{
        switch (type) {
        case IRQ_TYPE_NONE:
        case IRQ_TYPE_EDGE_BOTH:
                return 0;
        default:
                return -EINVAL;
        }
}

static struct irq_chip gpio_irqchip = {
        .name           = "GPIO",
        .mask           = gpio_irq_mask,
        .unmask         = gpio_irq_unmask,
        .set_type       = gpio_irq_type,
        .set_wake       = gpio_irq_set_wake,
};

static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
{
        unsigned        pin;
        struct irq_desc *gpio;
        struct at91_gpio_chip *at91_gpio;
        void __iomem    *pio;
        u32             isr;

        at91_gpio = get_irq_chip_data(irq);
        pio = at91_gpio->regbase;

        /* temporarily mask (level sensitive) parent IRQ */
        desc->chip->ack(irq);
        for (;;) {
                /* Reading ISR acks pending (edge triggered) GPIO interrupts.
                 * When there none are pending, we're finished unless we need
                 * to process multiple banks (like ID_PIOCDE on sam9263).
                 */
                isr = __raw_readl(pio + PIO_ISR) & __raw_readl(pio + PIO_IMR);
                if (!isr) {
                        if (!at91_gpio->next)
                                break;
                        at91_gpio = at91_gpio->next;
                        pio = at91_gpio->regbase;
                        continue;
                }

                pin = at91_gpio->chip.base;
                gpio = &irq_desc[pin];

                while (isr) {
                        if (isr & 1) {
                                if (unlikely(gpio->depth)) {
                                        /*
                                         * The core ARM interrupt handler lazily disables IRQs so
                                         * another IRQ must be generated before it actually gets
                                         * here to be disabled on the GPIO controller.
                                         */
                                        gpio_irq_mask(pin);
                                }
                                else
                                        generic_handle_irq(pin);
                        }
                        pin++;
                        gpio++;
                        isr >>= 1;
                }
        }
        desc->chip->unmask(irq);
        /* now it may re-trigger */
}

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

#ifdef CONFIG_DEBUG_FS

static int at91_gpio_show(struct seq_file *s, void *unused)
{
        int bank, j;

        /* print heading */
        seq_printf(s, "Pin\t");
        for (bank = 0; bank < gpio_banks; bank++) {
                seq_printf(s, "PIO%c\t", 'A' + bank);
        };
        seq_printf(s, "\n\n");

        /* print pin status */
        for (j = 0; j < 32; j++) {
                seq_printf(s, "%i:\t", j);

                for (bank = 0; bank < gpio_banks; bank++) {
                        unsigned        pin  = PIN_BASE + (32 * bank) + j;
                        void __iomem    *pio = pin_to_controller(pin);
                        unsigned        mask = pin_to_mask(pin);

                        if (__raw_readl(pio + PIO_PSR) & mask)
                                seq_printf(s, "GPIO:%s", __raw_readl(pio + PIO_PDSR) & mask ? "1" : "0");
                        else
                                seq_printf(s, "%s", __raw_readl(pio + PIO_ABSR) & mask ? "B" : "A");

                        seq_printf(s, "\t");
                }

                seq_printf(s, "\n");
        }

        return 0;
}

static int at91_gpio_open(struct inode *inode, struct file *file)
{
        return single_open(file, at91_gpio_show, NULL);
}

static const struct file_operations at91_gpio_operations = {
        .open           = at91_gpio_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static int __init at91_gpio_debugfs_init(void)
{
        /* /sys/kernel/debug/at91_gpio */
        (void) debugfs_create_file("at91_gpio", S_IFREG | S_IRUGO, NULL, NULL, &at91_gpio_operations);
        return 0;
}
postcore_initcall(at91_gpio_debugfs_init);

#endif

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

/*
 * This lock class tells lockdep that GPIO irqs are in a different
 * category than their parents, so it won't report false recursion.
 */
static struct lock_class_key gpio_lock_class;

/*
 * Called from the processor-specific init to enable GPIO interrupt support.
 */
void __init at91_gpio_irq_setup(void)
{
        unsigned                pioc, pin;
        struct at91_gpio_chip   *this, *prev;

        for (pioc = 0, pin = PIN_BASE, this = gpio_chip, prev = NULL;
                        pioc++ < gpio_banks;
                        prev = this, this++) {
                unsigned        id = this->bank->id;
                unsigned        i;

                __raw_writel(~0, this->regbase + PIO_IDR);

                for (i = 0, pin = this->chip.base; i < 32; i++, pin++) {
                        lockdep_set_class(&irq_desc[pin].lock, &gpio_lock_class);

                        /*
                         * Can use the "simple" and not "edge" handler since it's
                         * shorter, and the AIC handles interrupts sanely.
                         */
                        set_irq_chip(pin, &gpio_irqchip);
                        set_irq_handler(pin, handle_simple_irq);
                        set_irq_flags(pin, IRQF_VALID);
                }

                /* The toplevel handler handles one bank of GPIOs, except
                 * AT91SAM9263_ID_PIOCDE handles three... PIOC is first in
                 * the list, so we only set up that handler.
                 */
                if (prev && prev->next == this)
                        continue;

                set_irq_chip_data(id, this);
                set_irq_chained_handler(id, gpio_irq_handler);
        }
        pr_info("AT91: %d gpio irqs in %d banks\n", pin - PIN_BASE, gpio_banks);
}

/* gpiolib support */
static int at91_gpiolib_direction_input(struct gpio_chip *chip,
                                        unsigned offset)
{
        struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
        void __iomem *pio = at91_gpio->regbase;
        unsigned mask = 1 << offset;

        __raw_writel(mask, pio + PIO_ODR);
        return 0;
}

static int at91_gpiolib_direction_output(struct gpio_chip *chip,
                                         unsigned offset, int val)
{
        struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
        void __iomem *pio = at91_gpio->regbase;
        unsigned mask = 1 << offset;

        __raw_writel(mask, pio + (val ? PIO_SODR : PIO_CODR));
        __raw_writel(mask, pio + PIO_OER);
        return 0;
}

static int at91_gpiolib_get(struct gpio_chip *chip, unsigned offset)
{
        struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
        void __iomem *pio = at91_gpio->regbase;
        unsigned mask = 1 << offset;
        u32 pdsr;

        pdsr = __raw_readl(pio + PIO_PDSR);
        return (pdsr & mask) != 0;
}

static void at91_gpiolib_set(struct gpio_chip *chip, unsigned offset, int val)
{
        struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
        void __iomem *pio = at91_gpio->regbase;
        unsigned mask = 1 << offset;

        __raw_writel(mask, pio + (val ? PIO_SODR : PIO_CODR));
}

static void at91_gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
        int i;

        for (i = 0; i < chip->ngpio; i++) {
                unsigned pin = chip->base + i;
                void __iomem *pio = pin_to_controller(pin);
                unsigned mask = pin_to_mask(pin);
                const char *gpio_label;

                gpio_label = gpiochip_is_requested(chip, i);
                if (gpio_label) {
                        seq_printf(s, "[%s] GPIO%s%d: ",
                                   gpio_label, chip->label, i);
                        if (__raw_readl(pio + PIO_PSR) & mask)
                                seq_printf(s, "[gpio] %s\n",
                                           at91_get_gpio_value(pin) ?
                                           "set" : "clear");
                        else
                                seq_printf(s, "[periph %s]\n",
                                           __raw_readl(pio + PIO_ABSR) &
                                           mask ? "B" : "A");
                }
        }
}

/*
 * Called from the processor-specific init to enable GPIO pin support.
 */
void __init at91_gpio_init(struct at91_gpio_bank *data, int nr_banks)
{
        unsigned                i;
        struct at91_gpio_chip *at91_gpio, *last = NULL;

        BUG_ON(nr_banks > MAX_GPIO_BANKS);

        gpio_banks = nr_banks;

        for (i = 0; i < nr_banks; i++) {
                at91_gpio = &gpio_chip[i];

                at91_gpio->bank = &data[i];
                at91_gpio->chip.base = PIN_BASE + i * 32;
                at91_gpio->regbase = at91_gpio->bank->offset +
                        (void __iomem *)AT91_VA_BASE_SYS;

                /* enable PIO controller's clock */
                clk_enable(at91_gpio->bank->clock);

                /* AT91SAM9263_ID_PIOCDE groups PIOC, PIOD, PIOE */
                if (last && last->bank->id == at91_gpio->bank->id)
                        last->next = at91_gpio;
                last = at91_gpio;

                gpiochip_add(&at91_gpio->chip);
        }
}