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1/* SPDX-License-Identifier: GPL-2.0-or-later */2/*3 * lm75.h - Part of lm_sensors, Linux kernel modules for hardware monitoring4 * Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com>5 */6 7/*8 * This file contains common code for encoding/decoding LM75 type9 * temperature readings, which are emulated by many of the chips10 * we support. As the user is unlikely to load more than one driver11 * which contains this code, we don't worry about the wasted space.12 */13 14#include <linux/minmax.h>15#include <linux/types.h>16 17/* straight from the datasheet */18#define LM75_TEMP_MIN (-55000)19#define LM75_TEMP_MAX 12500020#define LM75_SHUTDOWN 0x0121 22/*23 * TEMP: 0.001C/bit (-55C to +125C)24 * REG: (0.5C/bit, two's complement) << 725 */26static inline u16 LM75_TEMP_TO_REG(long temp)27{28 int ntemp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);29 30 ntemp += (ntemp < 0 ? -250 : 250);31 return (u16)((ntemp / 500) << 7);32}33 34static inline int LM75_TEMP_FROM_REG(u16 reg)35{36 /*37 * use integer division instead of equivalent right shift to38 * guarantee arithmetic shift and preserve the sign39 */40 return ((s16)reg / 128) * 500;41}42