lm75.h

LM75温度侦测芯片

#ifndef LM75_H
#define	LM75_H
/*
 *  lm75.h
 *
 *  Copyright (C) 2006  Apple zeng
 *
 *
 * 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.
 */

/* straight from the datasheet */
#define LM75_TEMP_MIN (-55000)
#define LM75_TEMP_MAX 125000

/* This macro is used to scale user-input to sensible values in almost all
   chip drivers. */
static inline int SENSORS_LIMIT(long value, long low, long high)
{
    if (value < low)
        return low;
    else if (value > high)
        return high;
    else
        return value;
}

/* TEMP: 0.001C/bit (-55C to +125C)
   REG: (0.5C/bit, two's complement) << 7 */
static inline unsigned short LM75_TEMP_TO_REG(int temp)
{
    int ntemp = SENSORS_LIMIT(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
    ntemp += (ntemp<0 ? -250 : 250);
    return (unsigned short)((ntemp / 500) << 7);
}

static inline int LM75_TEMP_FROM_REG(unsigned short reg)
{
    /* use integer division instead of equivalent right shift to
       guarantee arithmetic shift and preserve the sign */
    return ((unsigned short)reg / 128) * 500;
}

#define I2C_LM75 		0x96
#endif