gpio-ks8695.c

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/*
 * arch/arm/mach-ks8695/gpio.c
 *
 * Copyright (C) 2006 Andrew Victor
 * Updated to GPIOLIB, Copyright 2008 Simtec Electronics
 *                     Daniel Silverstone <[email protected]>
 *
 * 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/gpio.h>
#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-ks8695.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 */
    irq_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