| /* 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; |
| } |
