42 lines
1.1 KiB
C
42 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
/*
|
|
* lm75.h - Part of lm_sensors, Linux kernel modules for hardware monitoring
|
|
* Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com>
|
|
*/
|
|
|
|
/*
|
|
* This file contains common code for encoding/decoding LM75 type
|
|
* temperature readings, which are emulated by many of the chips
|
|
* we support. As the user is unlikely to load more than one driver
|
|
* which contains this code, we don't worry about the wasted space.
|
|
*/
|
|
|
|
#include <linux/minmax.h>
|
|
#include <linux/types.h>
|
|
|
|
/* straight from the datasheet */
|
|
#define LM75_TEMP_MIN (-55000)
|
|
#define LM75_TEMP_MAX 125000
|
|
#define LM75_SHUTDOWN 0x01
|
|
|
|
/*
|
|
* TEMP: 0.001C/bit (-55C to +125C)
|
|
* REG: (0.5C/bit, two's complement) << 7
|
|
*/
|
|
static inline u16 LM75_TEMP_TO_REG(long temp)
|
|
{
|
|
int ntemp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
|
|
|
|
ntemp += (ntemp < 0 ? -250 : 250);
|
|
return (u16)((ntemp / 500) << 7);
|
|
}
|
|
|
|
static inline int LM75_TEMP_FROM_REG(u16 reg)
|
|
{
|
|
/*
|
|
* use integer division instead of equivalent right shift to
|
|
* guarantee arithmetic shift and preserve the sign
|
|
*/
|
|
return ((s16)reg / 128) * 500;
|
|
}
|