path: root/drivers/hwmon/lm90.c

/*
 * lm90.c - Part of lm_sensors, Linux kernel modules for hardware
 *          monitoring
 * Copyright (C) 2003-2010  Jean Delvare <khali@linux-fr.org>
 *
 * Based on the lm83 driver. The LM90 is a sensor chip made by National
 * Semiconductor. It reports up to two temperatures (its own plus up to
 * one external one) with a 0.125 deg resolution (1 deg for local
 * temperature) and a 3-4 deg accuracy.
 *
 * This driver also supports the LM89 and LM99, two other sensor chips
 * made by National Semiconductor. Both have an increased remote
 * temperature measurement accuracy (1 degree), and the LM99
 * additionally shifts remote temperatures (measured and limits) by 16
 * degrees, which allows for higher temperatures measurement.
 * Note that there is no way to differentiate between both chips.
 * When device is auto-detected, the driver will assume an LM99.
 *
 * This driver also supports the LM86, another sensor chip made by
 * National Semiconductor. It is exactly similar to the LM90 except it
 * has a higher accuracy.
 *
 * This driver also supports the ADM1032, a sensor chip made by Analog
 * Devices. That chip is similar to the LM90, with a few differences
 * that are not handled by this driver. Among others, it has a higher
 * accuracy than the LM90, much like the LM86 does.
 *
 * This driver also supports the MAX6657, MAX6658 and MAX6659 sensor
 * chips made by Maxim. These chips are similar to the LM86.
 * Note that there is no easy way to differentiate between the three
 * variants. We use the device address to detect MAX6659, which will result
 * in a detection as max6657 if it is on address 0x4c. The extra address
 * and features of the MAX6659 are only supported if the chip is configured
 * explicitly as max6659, or if its address is not 0x4c.
 * These chips lack the remote temperature offset feature.
 *
 * This driver also supports the MAX6646, MAX6647, MAX6648, MAX6649 and
 * MAX6692 chips made by Maxim.  These are again similar to the LM86,
 * but they use unsigned temperature values and can report temperatures
 * from 0 to 145 degrees.
 *
 * This driver also supports the MAX6680 and MAX6681, two other sensor
 * chips made by Maxim. These are quite similar to the other Maxim
 * chips. The MAX6680 and MAX6681 only differ in the pinout so they can
 * be treated identically.
 *
 * This driver also supports the MAX6695 and MAX6696, two other sensor
 * chips made by Maxim. These are also quite similar to other Maxim
 * chips, but support three temperature sensors instead of two. MAX6695
 * and MAX6696 only differ in the pinout so they can be treated identically.
 *
 * This driver also supports the ADT7461 chip from Analog Devices.
 * It's supported in both compatibility and extended mode. It is mostly
 * compatible with LM90 except for a data format difference for the
 * temperature value registers.
 *
 * Since the LM90 was the first chipset supported by this driver, most
 * comments will refer to this chipset, but are actually general and
 * concern all supported chipsets, unless mentioned otherwise.
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon-sysfs.h>
#include <linux/hwmon.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>

/*
 * Addresses to scan
 * Address is fully defined internally and cannot be changed except for
 * MAX6659, MAX6680 and MAX6681.
 * LM86, LM89, LM90, LM99, ADM1032, ADM1032-1, ADT7461, MAX6649, MAX6657
 * and MAX6658 have address 0x4c.
 * ADM1032-2, ADT7461-2, LM89-1, LM99-1 and MAX6646 have address 0x4d.
 * MAX6647 has address 0x4e.
 * MAX6659 can have address 0x4c, 0x4d or 0x4e.
 * MAX6680 and MAX6681 can have address 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b,
 * 0x4c, 0x4d or 0x4e.
 */

static const unsigned short normal_i2c[] = {
	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };

enum chips { lm90, adm1032, lm99, lm86,