[linux.git] / drivers / hwmon / lm75.h

/*
    lm75.h - Part of lm_sensors, Linux kernel modules for hardware
	      monitoring
    Copyright (c) 2003 Mark M. Hoffman <[email protected]>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/*
    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/kernel.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;
}
Commit	Line	Data
1da177e4 LT	1	/*
1da177e4 LT	2	lm75.h - Part of lm_sensors, Linux kernel modules for hardware
a01a6847	3	monitoring
1da177e4 LT	4	Copyright (c) 2003 Mark M. Hoffman <[email protected]>
	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
5a4c0601	28	#include <linux/kernel.h>
1da177e4 LT	29
	30	/* straight from the datasheet */
	31	#define LM75_TEMP_MIN (-55000)
	32	#define LM75_TEMP_MAX 125000
9914518e	33	#define LM75_SHUTDOWN 0x01
1da177e4 LT	34
	35	/* TEMP: 0.001C/bit (-55C to +125C)
	36	REG: (0.5C/bit, two's complement) << 7 */
5bfedac0	37	static inline u16 LM75_TEMP_TO_REG(long temp)
1da177e4	38	{
2a844c14	39	int ntemp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
a01a6847	40	ntemp += (ntemp < 0 ? -250 : 250);
1da177e4 LT	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	}