c2port-duramar2150.c

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/*
 *  Silicon Labs C2 port Linux support for Eurotech Duramar 2150
 *
 *  Copyright (c) 2008 Rodolfo Giometti <[email protected]>
 *  Copyright (c) 2008 Eurotech S.p.A. <[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
 */

#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/c2port.h>

#define DATA_PORT   0x325
#define DIR_PORT    0x326
#define    C2D         (1 << 0)
#define    C2CK        (1 << 1)

static DEFINE_MUTEX(update_lock);

/*
 * C2 port operations
 */

static void duramar2150_c2port_access(struct c2port_device *dev, int status)
{
    u8 v;

    mutex_lock(&update_lock);

    v = inb(DIR_PORT);

    /* 0 = input, 1 = output */
    if (status)
        outb(v | (C2D | C2CK), DIR_PORT);
    else
        /* When access is "off" is important that both lines are set
         * as inputs or hi-impedance */
        outb(v & ~(C2D | C2CK), DIR_PORT);

    mutex_unlock(&update_lock);
}

static void duramar2150_c2port_c2d_dir(struct c2port_device *dev, int dir)
{
    u8 v;

    mutex_lock(&update_lock);

    v = inb(DIR_PORT);

    if (dir)
        outb(v & ~C2D, DIR_PORT);
    else
        outb(v | C2D, DIR_PORT);

    mutex_unlock(&update_lock);
}

static int duramar2150_c2port_c2d_get(struct c2port_device *dev)
{
    return inb(DATA_PORT) & C2D;
}

static void duramar2150_c2port_c2d_set(struct c2port_device *dev, int status)
{
    u8 v;

    mutex_lock(&update_lock);

    v = inb(DATA_PORT);

    if (status)
        outb(v | C2D, DATA_PORT);
    else
        outb(v & ~C2D, DATA_PORT);

    mutex_unlock(&update_lock);
}

static void duramar2150_c2port_c2ck_set(struct c2port_device *dev, int status)
{
    u8 v;

    mutex_lock(&update_lock);

    v = inb(DATA_PORT);

    if (status)
        outb(v | C2CK, DATA_PORT);
    else
        outb(v & ~C2CK, DATA_PORT);

    mutex_unlock(&update_lock);
}

static struct c2port_ops duramar2150_c2port_ops = {
    .block_size = 512,  /* bytes */
    .blocks_num = 30,   /* total flash size: 15360 bytes */

    .access     = duramar2150_c2port_access,
    .c2d_dir    = duramar2150_c2port_c2d_dir,
    .c2d_get    = duramar2150_c2port_c2d_get,
    .c2d_set    = duramar2150_c2port_c2d_set,
    .c2ck_set   = duramar2150_c2port_c2ck_set,
};

static struct c2port_device *duramar2150_c2port_dev;

/*
 * Module stuff
 */

static int __init duramar2150_c2port_init(void)
{
    struct resource *res;
    int ret = 0;

    res = request_region(0x325, 2, "c2port");
    if (!res)
        return -EBUSY;

    duramar2150_c2port_dev = c2port_device_register("uc",
                    &duramar2150_c2port_ops, NULL);
    if (!duramar2150_c2port_dev) {
        ret = -ENODEV;
        goto free_region;
    }

    return 0;

free_region:
    release_region(0x325, 2);
    return ret;
}

static void __exit duramar2150_c2port_exit(void)
{
    /* Setup the GPIOs as input by default (access = 0) */
    duramar2150_c2port_access(duramar2150_c2port_dev, 0);

    c2port_device_unregister(duramar2150_c2port_dev);

    release_region(0x325, 2);
}

module_init(duramar2150_c2port_init);
module_exit(duramar2150_c2port_exit);

MODULE_AUTHOR("Rodolfo Giometti <[email protected]>");
MODULE_DESCRIPTION("Silicon Labs C2 port Linux support for Duramar 2150");
MODULE_LICENSE("GPL");