/*
 * arch/arm/mach-ks8695/gpio.c
 *
 * Copyright (C) 2006 Andrew Victor
 * Updated to GPIOLIB, Copyright 2008 Simtec Electronics
 *                     Daniel Silverstone <dsilvers@simtec.co.uk>
 *
 * 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.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <asm/mach/irq.h>

#include <mach/regs-gpio.h>
#include <mach/gpio.h>

/*
 * Configure a GPIO line for either GPIO function, or its internal
 * function (Interrupt, Timer, etc).
 */
static void ks8695_gpio_mode(unsigned int pin, short gpio)
{
        unsigned int enable[] = { IOPC_IOEINT0EN, IOPC_IOEINT1EN, IOPC_IOEINT2EN, IOPC_IOEINT3EN, IOPC_IOTIM0EN, IOPC_IOTIM1EN };
        unsigned long x, flags;

        if (pin > KS8695_GPIO_5)        /* only GPIO 0..5 have internal functions */
                return;

        local_irq_save(flags);

        x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPC);
        if (gpio)                       /* GPIO: set bit to 0 */
                x &= ~enable[pin];
        else                            /* Internal function: set bit to 1 */
                x |= enable[pin];
        __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPC);

        local_irq_restore(flags);
}


static unsigned short gpio_irq[] = { KS8695_IRQ_EXTERN0, KS8695_IRQ_EXTERN1, KS8695_IRQ_EXTERN2, KS8695_IRQ_EXTERN3 };

/*
 * Configure GPIO pin as external interrupt source.
 */
int ks8695_gpio_interrupt(unsigned int pin, unsigned int type)
{
        unsigned long x, flags;

        if (pin > KS8695_GPIO_3)        /* only GPIO 0..3 can generate IRQ */
                return -EINVAL;

        local_irq_save(flags);

        /* set pin as input */
        x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPM);
        x &= ~IOPM(pin);
        __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPM);

        local_irq_restore(flags);

        /* Set IRQ triggering type */
        set_irq_type(gpio_irq[pin], type);

        /* enable interrupt mode */
        ks8695_gpio_mode(pin, 0);

        return 0;
}
EXPORT_SYMBOL(ks8695_gpio_interrupt);



/* .... Generic GPIO interface .............................................. */

/*
 * Configure the GPIO line as an input.
 */
static int ks8695_gpio_direction_input(struct gpio_chip *gc, unsigned int pin)
{
        unsigned long x, flags;

        if (pin > KS8695_GPIO_15)
                return -EINVAL;

        /* set pin to GPIO mode */
        ks8695_gpio_mode(pin, 1);

        local_irq_save(flags);

        /* set pin as input */
        x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPM);
        x &= ~IOPM(pin);
        __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPM);

        local_irq_restore(flags);

        return 0;
}


/*
 * Configure the GPIO line as an output, with default state.
 */
static int ks8695_gpio_direction_output(struct gpio_chip *gc,
                                        unsigned int pin, int state)
{
        unsigned long x, flags;

        if (pin > KS8695_GPIO_15)
                return -EINVAL;

        /* set pin to GPIO mode */
        ks8695_gpio_mode(pin, 1);

        local_irq_save(flags);

        /* set line state */
        x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPD);
        if (state)
                x |= IOPD(pin);
        else
                x &= ~IOPD(pin);
        __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPD);

        /* set pin as output */
        x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPM);
        x |= IOPM(pin);
        __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPM);

        local_irq_restore(flags);

        return 0;
}


/*
 * Set the state of an output GPIO line.
 */
static void ks8695_gpio_set_value(struct gpio_chip *gc,
                                  unsigned int pin, int state)
{
        unsigned long x, flags;

        if (pin > KS8695_GPIO_15)
                return;

        local_irq_save(flags);

        /* set output line state */
        x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPD);
        if (state)
                x |= IOPD(pin);
        else
                x &= ~IOPD(pin);
        __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPD);

        local_irq_restore(flags);
}


/*
 * Read the state of a GPIO line.
 */
static int ks8695_gpio_get_value(struct gpio_chip *gc, unsigned int pin)
{
        unsigned long x;

        if (pin > KS8695_GPIO_15)
                return -EINVAL;

        x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPD);
        return (x & IOPD(pin)) != 0;
}


/*
 * Map GPIO line to IRQ number.
 */
static int ks8695_gpio_to_irq(struct gpio_chip *gc, unsigned int pin)
{
        if (pin > KS8695_GPIO_3)        /* only GPIO 0..3 can generate IRQ */
                return -EINVAL;

        return gpio_irq[pin];
}

/*
 * Map IRQ number to GPIO line.
 */
int irq_to_gpio(unsigned int irq)
{
        if ((irq < KS8695_IRQ_EXTERN0) || (irq > KS8695_IRQ_EXTERN3))
                return -EINVAL;

        return (irq - KS8695_IRQ_EXTERN0);
}
EXPORT_SYMBOL(irq_to_gpio);

/* GPIOLIB interface */

static struct gpio_chip ks8695_gpio_chip = {
        .label                  = "KS8695",
        .direction_input        = ks8695_gpio_direction_input,
        .direction_output       = ks8695_gpio_direction_output,
        .get                    = ks8695_gpio_get_value,
        .set                    = ks8695_gpio_set_value,
        .to_irq                 = ks8695_gpio_to_irq,
        .base                   = 0,
        .ngpio                  = 16,
        .can_sleep              = 0,
};

/* Register the GPIOs */
void ks8695_register_gpios(void)
{
        if (gpiochip_add(&ks8695_gpio_chip))
                printk(KERN_ERR "Unable to register core GPIOs\n");
}

/* .... Debug interface ..................................................... */

#ifdef CONFIG_DEBUG_FS

static int ks8695_gpio_show(struct seq_file *s, void *unused)
{
        unsigned int enable[] = { IOPC_IOEINT0EN, IOPC_IOEINT1EN, IOPC_IOEINT2EN, IOPC_IOEINT3EN, IOPC_IOTIM0EN, IOPC_IOTIM1EN };
        unsigned int intmask[] = { IOPC_IOEINT0TM, IOPC_IOEINT1TM, IOPC_IOEINT2TM, IOPC_IOEINT3TM };
        unsigned long mode, ctrl, data;
        int i;

        mode = __raw_readl(KS8695_GPIO_VA + KS8695_IOPM);
        ctrl = __raw_readl(KS8695_GPIO_VA + KS8695_IOPC);
        data = __raw_readl(KS8695_GPIO_VA + KS8695_IOPD);

        seq_printf(s, "Pin\tI/O\tFunction\tState\n\n");

        for (i = KS8695_GPIO_0; i <= KS8695_GPIO_15 ; i++) {
                seq_printf(s, "%i:\t", i);

                seq_printf(s, "%s\t", (mode & IOPM(i)) ? "Output" : "Input");

                if (i <= KS8695_GPIO_3) {
                        if (ctrl & enable[i]) {
                                seq_printf(s, "EXT%i ", i);

                                switch ((ctrl & intmask[i]) >> (4 * i)) {
                                        case IOPC_TM_LOW:
                                                seq_printf(s, "(Low)");         break;
                                        case IOPC_TM_HIGH:
                                                seq_printf(s, "(High)");        break;
                                        case IOPC_TM_RISING:
                                                seq_printf(s, "(Rising)");      break;
                                        case IOPC_TM_FALLING:
                                                seq_printf(s, "(Falling)");     break;
                                        case IOPC_TM_EDGE:
                                                seq_printf(s, "(Edges)");       break;
                                }
                        }
                        else
                                seq_printf(s, "GPIO\t");
                }
                else if (i <= KS8695_GPIO_5) {
                        if (ctrl & enable[i])
                                seq_printf(s, "TOUT%i\t", i - KS8695_GPIO_4);
                        else
                                seq_printf(s, "GPIO\t");
                }
                else
                        seq_printf(s, "GPIO\t");

                seq_printf(s, "\t");

                seq_printf(s, "%i\n", (data & IOPD(i)) ? 1 : 0);
        }
        return 0;
}

static int ks8695_gpio_open(struct inode *inode, struct file *file)
{
        return single_open(file, ks8695_gpio_show, NULL);
}

static const struct file_operations ks8695_gpio_operations = {
        .open           = ks8695_gpio_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static int __init ks8695_gpio_debugfs_init(void)
{
        /* /sys/kernel/debug/ks8695_gpio */
        (void) debugfs_create_file("ks8695_gpio", S_IFREG | S_IRUGO, NULL, NULL, &ks8695_gpio_operations);
        return 0;
}
postcore_initcall(ks8695_gpio_debugfs_init);

#endif