projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 74ba9207 | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| 1da177e4 | 2 | /* |
| 8cbf2172 MO |
3 | * lm75.h - Part of lm_sensors, Linux kernel modules for hardware monitoring |
| 4 | * Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com> | |
| 5 | */ | |
| 1da177e4 LT |
6 | |
| 7 | /* | |
| 8cbf2172 MO |
8 | * This file contains common code for encoding/decoding LM75 type |
| 9 | * temperature readings, which are emulated by many of the chips | |
| 10 | * we support. As the user is unlikely to load more than one driver | |
| 11 | * which contains this code, we don't worry about the wasted space. | |
| 12 | */ | |
| 1da177e4 | 13 | |
| 39397ba8 CJ |
14 | #include <linux/minmax.h> |
| 15 | #include <linux/types.h> | |
| 1da177e4 LT |
16 | |
| 17 | /* straight from the datasheet */ | |
| 18 | #define LM75_TEMP_MIN (-55000) | |
| 19 | #define LM75_TEMP_MAX 125000 | |
| 9914518e | 20 | #define LM75_SHUTDOWN 0x01 |
| 1da177e4 | 21 | |
| 8cbf2172 MO |
22 | /* |
| 23 | * TEMP: 0.001C/bit (-55C to +125C) | |
| 24 | * REG: (0.5C/bit, two's complement) << 7 | |
| 25 | */ | |
| 5bfedac0 | 26 | static inline u16 LM75_TEMP_TO_REG(long temp) |
| 1da177e4 | 27 | { |
| 2a844c14 | 28 | int ntemp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX); |
| 8cbf2172 | 29 | |
| a01a6847 | 30 | ntemp += (ntemp < 0 ? -250 : 250); |
| 1da177e4 LT |
31 | return (u16)((ntemp / 500) << 7); |
| 32 | } | |
| 33 | ||
| 34 | static inline int LM75_TEMP_FROM_REG(u16 reg) | |
| 35 | { | |
| 8cbf2172 MO |
36 | /* |
| 37 | * use integer division instead of equivalent right shift to | |
| 38 | * guarantee arithmetic shift and preserve the sign | |
| 39 | */ | |
| 1da177e4 LT |
40 | return ((s16)reg / 128) * 500; |
| 41 | } |