| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* |
| 2 | lm75.h - Part of lm_sensors, Linux kernel modules for hardware |
| 3 | monitoring |
| 4 | Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com> |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 19 | */ |
| 20 | |
| 21 | /* |
| 22 | This file contains common code for encoding/decoding LM75 type |
| 23 | temperature readings, which are emulated by many of the chips |
| 24 | we support. As the user is unlikely to load more than one driver |
| 25 | which contains this code, we don't worry about the wasted space. |
| 26 | */ |
| 27 | |
| 28 | #include <linux/hwmon.h> |
| 29 | |
| 30 | /* straight from the datasheet */ |
| 31 | #define LM75_TEMP_MIN (-55000) |
| 32 | #define LM75_TEMP_MAX 125000 |
| 33 | #define LM75_SHUTDOWN 0x01 |
| 34 | |
| 35 | /* TEMP: 0.001C/bit (-55C to +125C) |
| 36 | REG: (0.5C/bit, two's complement) << 7 */ |
| 37 | static inline u16 LM75_TEMP_TO_REG(long temp) |
| 38 | { |
| 39 | int ntemp = SENSORS_LIMIT(temp, LM75_TEMP_MIN, LM75_TEMP_MAX); |
| 40 | ntemp += (ntemp < 0 ? -250 : 250); |
| 41 | return (u16)((ntemp / 500) << 7); |
| 42 | } |
| 43 | |
| 44 | static inline int LM75_TEMP_FROM_REG(u16 reg) |
| 45 | { |
| 46 | /* use integer division instead of equivalent right shift to |
| 47 | guarantee arithmetic shift and preserve the sign */ |
| 48 | return ((s16)reg / 128) * 500; |
| 49 | } |