linux-imx

/*

 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>

 *

 * 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.

 *

 * 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.

 */

​

#include <asm/io.h>

​

#include <linux/delay.h>

#include <linux/moduleparam.h>

#include <linux/module.h>

​

#include "w1_internal.h"

​

static int w1_delay_parm = 1;

module_param_named(delay_coef, w1_delay_parm, int, 0);

​

static int w1_disable_irqs = 0;

module_param_named(disable_irqs, w1_disable_irqs, int, 0);

​

static u8 w1_crc8_table[] = {

    0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,

    157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,

    35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,

    190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,

    70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,

    219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,

    101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,

    248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,

    140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,

    17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,

    175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,

    50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,

    202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,

    87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,

    233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,

    116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53

};

​

static void w1_delay(unsigned long tm)

{

    udelay(tm * w1_delay_parm);

}

​

static void w1_write_bit(struct w1_master *dev, int bit);

static u8 w1_read_bit(struct w1_master *dev);

​

/**

 * w1_touch_bit() - Generates a write-0 or write-1 cycle and samples the level.

 * @dev:    the master device

 * @bit:    0 - write a 0, 1 - write a 0 read the level

 */

u8 w1_touch_bit(struct w1_master *dev, int bit)

{

    if (dev->bus_master->touch_bit)

        return dev->bus_master->touch_bit(dev->bus_master->data, bit);

    else if (bit)

        return w1_read_bit(dev);

    else {

        w1_write_bit(dev, 0);

        return 0;

    }

}

EXPORT_SYMBOL_GPL(w1_touch_bit);

​

/**

 * w1_write_bit() - Generates a write-0 or write-1 cycle.

 * @dev:    the master device

 * @bit:    bit to write

 *

 * Only call if dev->bus_master->touch_bit is NULL

 */

static void w1_write_bit(struct w1_master *dev, int bit)

{

    unsigned long flags = 0;

​

    if(w1_disable_irqs) local_irq_save(flags);

​

    if (bit) {

        dev->bus_master->write_bit(dev->bus_master->data, 0);

        w1_delay(6);

        dev->bus_master->write_bit(dev->bus_master->data, 1);

        w1_delay(64);

    } else {