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/* 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;
}
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