// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * lm90.c - Part of lm_sensors, Linux kernel modules for hardware
 *          monitoring
 * Copyright (C) 2003-2010  Jean Delvare <jdelvare@suse.de>
 *
 * 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 MAX6654 chip made by Maxim. This chip can
 * be at 9 different addresses, similar to MAX6680/MAX6681. The MAX6654 is
 * otherwise similar to MAX6657/MAX6658/MAX6659. Extended range is available
 * by setting the configuration register accordingly, and is done during
 * initialization. Extended precision is only available at conversion rates
 * of 1 Hz and slower. Note that extended precision is not enabled by
 * default, as this driver initializes all chips to 2 Hz by design.
 *
 * 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 ADT7461 and ADT7461A from Analog Devices as well as
 * NCT1008 from ON Semiconductor. The chips are supported in both compatibility
 * and extended mode. They are mostly compatible with LM90 except for a data
 * format difference for the temperature value registers.
 *
 * This driver also supports the SA56004 from Philips. This device is
 * pin-compatible with the LM86, the ED/EDP parts are also address-compatible.
 *
 * This driver also supports the G781 from GMT. This device is compatible
 * with the ADM1032.
 *
 * This driver also supports TMP451 from Texas Instruments. This device is
 * supported in both compatibility and extended mode. It's mostly compatible
 * with ADT7461 except for local temperature low byte register and max
 * conversion rate.
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/sysfs.h>
#include <linux/interrupt.h>
#include <linux/regulator/consumer.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, ADT7461A, MAX6649,
 * MAX6657, MAX6658, NCT1008 and W83L771 have address 0x4c.
 * ADM1032-2, ADT7461-2, ADT7461A-2, LM89-1, LM99-1, MAX6646, and NCT1008D
 * have address 0x4d.
 * MAX6647 has address 0x4e.
 * MAX6659 can have address 0x4c, 0x4d or 0x4e.
 * MAX6654, MAX6680, and MAX6681 can have address 0x18, 0x19, 0x1a, 0x29,
 * 0x2a, 0x2b, 0x4c, 0x4d or 0x4e.
 * SA56004 can have address 0x48 through 0x4F.
 */

static const unsigned short normal_i2c[] = {
        0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x48, 0x49, 0x4a, 0x4b, 0x4c,
        0x4d, 0x4e, 0x4f, I2C_CLIENT_END };

enum chips { lm90, adm1032, lm99, lm86, max6657, max6659, adt7461, max6680,
        max6646, w83l771, max6696, sa56004, g781, tmp451, max6654 };

/*
 * The LM90 registers
 */

#define LM90_REG_R_MAN_ID               0xFE
#define LM90_REG_R_CHIP_ID              0xFF
#define LM90_REG_R_CONFIG1              0x03
#define LM90_REG_W_CONFIG1              0x09
#define LM90_REG_R_CONFIG2              0xBF
#define LM90_REG_W_CONFIG2              0xBF
#define LM90_REG_R_CONVRATE             0x04
#define LM90_REG_W_CONVRATE             0x0A
#define LM90_REG_R_STATUS               0x02
#define LM90_REG_R_LOCAL_TEMP           0x00
#define LM90_REG_R_LOCAL_HIGH           0x05
#define LM90_REG_W_LOCAL_HIGH           0x0B
#define LM90_REG_R_LOCAL_LOW            0x06
#define LM90_REG_W_LOCAL_LOW            0x0C
#define LM90_REG_R_LOCAL_CRIT           0x20
#define LM90_REG_W_LOCAL_CRIT           0x20
#define LM90_REG_R_REMOTE_TEMPH         0x01
#define LM90_REG_R_REMOTE_TEMPL         0x10
#define LM90_REG_R_REMOTE_OFFSH         0x11
#define LM90_REG_W_REMOTE_OFFSH         0x11
#define LM90_REG_R_REMOTE_OFFSL         0x12
#define LM90_REG_W_REMOTE_OFFSL         0x12
#define LM90_REG_R_REMOTE_HIGHH         0x07
#define LM90_REG_W_REMOTE_HIGHH         0x0D
#define LM90_REG_R_REMOTE_HIGHL         0x13
#define LM90_REG_W_REMOTE_HIGHL         0x13
#define LM90_REG_R_REMOTE_LOWH          0x08
#define LM90_REG_W_REMOTE_LOWH          0x0E
#define LM90_REG_R_REMOTE_LOWL          0x14
#define LM90_REG_W_REMOTE_LOWL          0x14
#define LM90_REG_R_REMOTE_CRIT          0x19
#define LM90_REG_W_REMOTE_CRIT          0x19
#define LM90_REG_R_TCRIT_HYST           0x21
#define LM90_REG_W_TCRIT_HYST           0x21

/* MAX6646/6647/6649/6654/6657/6658/6659/6695/6696 registers */

#define MAX6657_REG_R_LOCAL_TEMPL       0x11
#define MAX6696_REG_R_STATUS2           0x12
#define MAX6659_REG_R_REMOTE_EMERG      0x16
#define MAX6659_REG_W_REMOTE_EMERG      0x16
#define MAX6659_REG_R_LOCAL_EMERG       0x17
#define MAX6659_REG_W_LOCAL_EMERG       0x17

/*  SA56004 registers */

#define SA56004_REG_R_LOCAL_TEMPL 0x22

#define LM90_MAX_CONVRATE_MS    16000   /* Maximum conversion rate in ms */

/* TMP451 registers */
#define TMP451_REG_R_LOCAL_TEMPL        0x15

/*
 * Device flags
 */
#define LM90_FLAG_ADT7461_EXT   (1 << 0) /* ADT7461 extended mode       */
/* Device features */
#define LM90_HAVE_OFFSET        (1 << 1) /* temperature offset register */
#define LM90_HAVE_REM_LIMIT_EXT (1 << 3) /* extended remote limit       */
#define LM90_HAVE_EMERGENCY     (1 << 4) /* 3rd upper (emergency) limit */
#define LM90_HAVE_EMERGENCY_ALARM (1 << 5)/* emergency alarm            */
#define LM90_HAVE_TEMP3         (1 << 6) /* 3rd temperature sensor      */
#define LM90_HAVE_BROKEN_ALERT  (1 << 7) /* Broken alert                */
#define LM90_PAUSE_FOR_CONFIG   (1 << 8) /* Pause conversion for config */

/* LM90 status */
#define LM90_STATUS_LTHRM       (1 << 0) /* local THERM limit tripped */
#define LM90_STATUS_RTHRM       (1 << 1) /* remote THERM limit tripped */
#define LM90_STATUS_ROPEN       (1 << 2) /* remote is an open circuit */
#define LM90_STATUS_RLOW        (1 << 3) /* remote low temp limit tripped */
#define LM90_STATUS_RHIGH       (1 << 4) /* remote high temp limit tripped */
#define LM90_STATUS_LLOW        (1 << 5) /* local low temp limit tripped */
#define LM90_STATUS_LHIGH       (1 << 6) /* local high temp limit tripped */

#define MAX6696_STATUS2_R2THRM  (1 << 1) /* remote2 THERM limit tripped */
#define MAX6696_STATUS2_R2OPEN  (1 << 2) /* remote2 is an open circuit */
#define MAX6696_STATUS2_R2LOW   (1 << 3) /* remote2 low temp limit tripped */
#define MAX6696_STATUS2_R2HIGH  (1 << 4) /* remote2 high temp limit tripped */
#define MAX6696_STATUS2_ROT2    (1 << 5) /* remote emergency limit tripped */
#define MAX6696_STATUS2_R2OT2   (1 << 6) /* remote2 emergency limit tripped */
#define MAX6696_STATUS2_LOT2    (1 << 7) /* local emergency limit tripped */

/*
 * Driver data (common to all clients)
 */

static const struct i2c_device_id lm90_id[] = {
        { "adm1032", adm1032 },
        { "adt7461", adt7461 },
        { "adt7461a", adt7461 },
        { "g781", g781 },
        { "lm90", lm90 },
        { "lm86", lm86 },
        { "lm89", lm86 },
        { "lm99", lm99 },
        { "max6646", max6646 },
        { "max6647", max6646 },
        { "max6649", max6646 },
        { "max6654", max6654 },
        { "max6657", max6657 },
        { "max6658", max6657 },
        { "max6659", max6659 },
        { "max6680", max6680 },
        { "max6681", max6680 },
        { "max6695", max6696 },
        { "max6696", max6696 },
        { "nct1008", adt7461 },
        { "w83l771", w83l771 },
        { "sa56004", sa56004 },
        { "tmp451", tmp451 },
        { }
};
MODULE_DEVICE_TABLE(i2c, lm90_id);

static const struct of_device_id __maybe_unused lm90_of_match[] = {
        {
                .compatible = "adi,adm1032",
                .data = (void *)adm1032
        },
        {
                .compatible = "adi,adt7461",
                .data = (void *)adt7461
        },
        {
                .compatible = "adi,adt7461a",
                .data = (void *)adt7461
        },
        {
                .compatible = "gmt,g781",
                .data = (void *)g781
        },
        {
                .compatible = "national,lm90",
                .data = (void *)lm90
        },
        {
                .compatible = "national,lm86",
                .data = (void *)lm86
        },
        {
                .compatible = "national,lm89",
                .data = (void *)lm86
        },
        {
                .compatible = "national,lm99",
                .data = (void *)lm99
        },
        {
                .compatible = "dallas,max6646",
                .data = (void *)max6646
        },
        {
                .compatible = "dallas,max6647",
                .data = (void *)max6646
        },
        {
                .compatible = "dallas,max6649",
                .data = (void *)max6646
        },
        {
                .compatible = "dallas,max6654",
                .data = (void *)max6654
        },
        {
                .compatible = "dallas,max6657",
                .data = (void *)max6657
        },
        {
                .compatible = "dallas,max6658",
                .data = (void *)max6657
        },
        {
                .compatible = "dallas,max6659",
                .data = (void *)max6659
        },
        {
                .compatible = "dallas,max6680",
                .data = (void *)max6680
        },
        {
                .compatible = "dallas,max6681",
                .data = (void *)max6680
        },
        {
                .compatible = "dallas,max6695",
                .data = (void *)max6696
        },
        {
                .compatible = "dallas,max6696",
                .data = (void *)max6696
        },
        {
                .compatible = "onnn,nct1008",
                .data = (void *)adt7461
        },
        {
                .compatible = "winbond,w83l771",
                .data = (void *)w83l771
        },
        {
                .compatible = "nxp,sa56004",
                .data = (void *)sa56004
        },
        {
                .compatible = "ti,tmp451",
                .data = (void *)tmp451
        },
        { },
};
MODULE_DEVICE_TABLE(of, lm90_of_match);

/*
 * chip type specific parameters
 */
struct lm90_params {
        u32 flags;              /* Capabilities */
        u16 alert_alarms;       /* Which alarm bits trigger ALERT# */
                                /* Upper 8 bits for max6695/96 */
        u8 max_convrate;        /* Maximum conversion rate register value */
        u8 reg_local_ext;       /* Extended local temp register (optional) */
};

static const struct lm90_params lm90_params[] = {
        [adm1032] = {
                .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT
                  | LM90_HAVE_BROKEN_ALERT,
                .alert_alarms = 0x7c,
                .max_convrate = 10,
        },
        [adt7461] = {
                .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT
                  | LM90_HAVE_BROKEN_ALERT,
                .alert_alarms = 0x7c,
                .max_convrate = 10,
        },
        [g781] = {
                .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT
                  | LM90_HAVE_BROKEN_ALERT,
                .alert_alarms = 0x7c,
                .max_convrate = 8,
        },
        [lm86] = {
                .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,
                .alert_alarms = 0x7b,
                .max_convrate = 9,
        },
        [lm90] = {
                .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,
                .alert_alarms = 0x7b,
                .max_convrate = 9,
        },
        [lm99] = {
                .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,
                .alert_alarms = 0x7b,
                .max_convrate = 9,
        },
        [max6646] = {
                .alert_alarms = 0x7c,
                .max_convrate = 6,
                .reg_local_ext = MAX6657_REG_R_LOCAL_TEMPL,
        },
        [max6654] = {
                .alert_alarms = 0x7c,
                .max_convrate = 7,
                .reg_local_ext = MAX6657_REG_R_LOCAL_TEMPL,
        },
        [max6657] = {
                .flags = LM90_PAUSE_FOR_CONFIG,
                .alert_alarms = 0x7c,
                .max_convrate = 8,
                .reg_local_ext = MAX6657_REG_R_LOCAL_TEMPL,
        },
        [max6659] = {
                .flags = LM90_HAVE_EMERGENCY,
                .alert_alarms = 0x7c,
                .max_convrate = 8,
                .reg_local_ext = MAX6657_REG_R_LOCAL_TEMPL,
        },
        [max6680] = {
                .flags = LM90_HAVE_OFFSET,
                .alert_alarms = 0x7c,
                .max_convrate = 7,
        },
        [max6696] = {
                .flags = LM90_HAVE_EMERGENCY
                  | LM90_HAVE_EMERGENCY_ALARM | LM90_HAVE_TEMP3,
                .alert_alarms = 0x1c7c,
                .max_convrate = 6,
                .reg_local_ext = MAX6657_REG_R_LOCAL_TEMPL,
        },
        [w83l771] = {
                .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,
                .alert_alarms = 0x7c,
                .max_convrate = 8,
        },
        [sa56004] = {
                .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,
                .alert_alarms = 0x7b,
                .max_convrate = 9,
                .reg_local_ext = SA56004_REG_R_LOCAL_TEMPL,
        },
        [tmp451] = {
                .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT
                  | LM90_HAVE_BROKEN_ALERT,
                .alert_alarms = 0x7c,
                .max_convrate = 9,
                .reg_local_ext = TMP451_REG_R_LOCAL_TEMPL,
        },
};

/*
 * TEMP8 register index
 */
enum lm90_temp8_reg_index {
        LOCAL_LOW = 0,
        LOCAL_HIGH,
        LOCAL_CRIT,
        REMOTE_CRIT,
        LOCAL_EMERG,    /* max6659 and max6695/96 */
        REMOTE_EMERG,   /* max6659 and max6695/96 */
        REMOTE2_CRIT,   /* max6695/96 only */
        REMOTE2_EMERG,  /* max6695/96 only */
        TEMP8_REG_NUM
};

/*
 * TEMP11 register index
 */
enum lm90_temp11_reg_index {
        REMOTE_TEMP = 0,
        REMOTE_LOW,
        REMOTE_HIGH,
        REMOTE_OFFSET,  /* except max6646, max6657/58/59, and max6695/96 */
        LOCAL_TEMP,
        REMOTE2_TEMP,   /* max6695/96 only */
        REMOTE2_LOW,    /* max6695/96 only */
        REMOTE2_HIGH,   /* max6695/96 only */
        TEMP11_REG_NUM
};

/*
 * Client data (each client gets its own)
 */

struct lm90_data {
        struct i2c_client *client;
        struct device *hwmon_dev;
        u32 channel_config[4];
        struct hwmon_channel_info temp_info;
        const struct hwmon_channel_info *info[3];
        struct hwmon_chip_info chip;
        struct mutex update_lock;
        bool valid;             /* true if register values are valid */
        unsigned long last_updated; /* in jiffies */
        int kind;
        u32 flags;

        unsigned int update_interval; /* in milliseconds */

        u8 config;              /* Current configuration register value */
        u8 config_orig;         /* Original configuration register value */
        u8 convrate_orig;       /* Original conversion rate register value */
        u16 alert_alarms;       /* Which alarm bits trigger ALERT# */
                                /* Upper 8 bits for max6695/96 */
        u8 max_convrate;        /* Maximum conversion rate */
        u8 reg_local_ext;       /* local extension register offset */

        /* registers values */
        s8 temp8[TEMP8_REG_NUM];
        s16 temp11[TEMP11_REG_NUM];
        u8 temp_hyst;
        u16 alarms; /* bitvector (upper 8 bits for max6695/96) */
};

/*
 * Support functions
 */

/*
 * The ADM1032 supports PEC but not on write byte transactions, so we need
 * to explicitly ask for a transaction without PEC.
 */
static inline s32 adm1032_write_byte(struct i2c_client *client, u8 value)
{
        return i2c_smbus_xfer(client->adapter, client->addr,
                              client->flags & ~I2C_CLIENT_PEC,
                              I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
}

/*
 * It is assumed that client->update_lock is held (unless we are in
 * detection or initialization steps). This matters when PEC is enabled,
 * because we don't want the address pointer to change between the write
 * byte and the read byte transactions.
 */
static int lm90_read_reg(struct i2c_client *client, u8 reg)
{
        int err;

        if (client->flags & I2C_CLIENT_PEC) {
                err = adm1032_write_byte(client, reg);
                if (err >= 0)
                        err = i2c_smbus_read_byte(client);
        } else
                err = i2c_smbus_read_byte_data(client, reg);

        return err;
}

static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl)
{
        int oldh, newh, l;

        /*
         * There is a trick here. We have to read two registers to have the
         * sensor temperature, but we have to beware a conversion could occur
         * between the readings. The datasheet says we should either use
         * the one-shot conversion register, which we don't want to do
         * (disables hardware monitoring) or monitor the busy bit, which is
         * impossible (we can't read the values and monitor that bit at the
         * exact same time). So the solution used here is to read the high
         * byte once, then the low byte, then the high byte again. If the new
         * high byte matches the old one, then we have a valid reading. Else
         * we have to read the low byte again, and now we believe we have a
         * correct reading.
         */
        oldh = lm90_read_reg(client, regh);
        if (oldh < 0)
                return oldh;
        l = lm90_read_reg(client, regl);
        if (l < 0)
                return l;
        newh = lm90_read_reg(client, regh);
        if (newh < 0)
                return newh;
        if (oldh != newh) {
                l = lm90_read_reg(client, regl);
                if (l < 0)
                        return l;
        }
        return (newh << 8) | l;
}

static int lm90_update_confreg(struct lm90_data *data, u8 config)
{
        if (data->config != config) {
                int err;

                err = i2c_smbus_write_byte_data(data->client,
                                                LM90_REG_W_CONFIG1,
                                                config);
                if (err)
                        return err;
                data->config = config;
        }
        return 0;
}

/*
 * client->update_lock must be held when calling this function (unless we are
 * in detection or initialization steps), and while a remote channel other
 * than channel 0 is selected. Also, calling code must make sure to re-select
 * external channel 0 before releasing the lock. This is necessary because
 * various registers have different meanings as a result of selecting a
 * non-default remote channel.
 */
static int lm90_select_remote_channel(struct lm90_data *data, int channel)
{
        int err = 0;

        if (data->kind == max6696) {
                u8 config = data->config & ~0x08;

                if (channel)
                        config |= 0x08;
                err = lm90_update_confreg(data, config);
        }
        return err;
}

static int lm90_write_convrate(struct lm90_data *data, int val)
{
        u8 config = data->config;
        int err;

        /* Save config and pause conversion */
        if (data->flags & LM90_PAUSE_FOR_CONFIG) {
                err = lm90_update_confreg(data, config | 0x40);
                if (err < 0)
                        return err;
        }

        /* Set conv rate */
        err = i2c_smbus_write_byte_data(data->client, LM90_REG_W_CONVRATE, val);

        /* Revert change to config */
        lm90_update_confreg(data, config);

        return err;
}

/*
 * Set conversion rate.
 * client->update_lock must be held when calling this function (unless we are
 * in detection or initialization steps).
 */
static int lm90_set_convrate(struct i2c_client *client, struct lm90_data *data,
                             unsigned int interval)
{
        unsigned int update_interval;
        int i, err;

        /* Shift calculations to avoid rounding errors */
        interval <<= 6;

        /* find the nearest update rate */
        for (i = 0, update_interval = LM90_MAX_CONVRATE_MS << 6;
             i < data->max_convrate; i++, update_interval >>= 1)
                if (interval >= update_interval * 3 / 4)
                        break;

        err = lm90_write_convrate(data, i);
        data->update_interval = DIV_ROUND_CLOSEST(update_interval, 64);
        return err;
}

static int lm90_update_limits(struct device *dev)
{
        struct lm90_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        int val;

        val = lm90_read_reg(client, LM90_REG_R_LOCAL_CRIT);
        if (val < 0)
                return val;
        data->temp8[LOCAL_CRIT] = val;

        val = lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT);
        if (val < 0)
                return val;
        data->temp8[REMOTE_CRIT] = val;

        val = lm90_read_reg(client, LM90_REG_R_TCRIT_HYST);
        if (val < 0)
                return val;
        data->temp_hyst = val;

        val = lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH);
        if (val < 0)
                return val;
        data->temp11[REMOTE_LOW] = val << 8;

        if (data->flags & LM90_HAVE_REM_LIMIT_EXT) {
                val = lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL);
                if (val < 0)
                        return val;
                data->temp11[REMOTE_LOW] |= val;
        }

        val = lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH);
        if (val < 0)
                return val;
        data->temp11[REMOTE_HIGH] = val << 8;

        if (data->flags & LM90_HAVE_REM_LIMIT_EXT) {
                val = lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL);
                if (val < 0)
                        return val;
                data->temp11[REMOTE_HIGH] |= val;
        }

        if (data->flags & LM90_HAVE_OFFSET) {
                val = lm90_read16(client, LM90_REG_R_REMOTE_OFFSH,
                                  LM90_REG_R_REMOTE_OFFSL);
                if (val < 0)
                        return val;
                data->temp11[REMOTE_OFFSET] = val;
        }

        if (data->flags & LM90_HAVE_EMERGENCY) {
                val = lm90_read_reg(client, MAX6659_REG_R_LOCAL_EMERG);
                if (val < 0)
                        return val;
                data->temp8[LOCAL_EMERG] = val;

                val = lm90_read_reg(client, MAX6659_REG_R_REMOTE_EMERG);
                if (val < 0)
                        return val;
                data->temp8[REMOTE_EMERG] = val;
        }

        if (data->kind == max6696) {
                val = lm90_select_remote_channel(data, 1);
                if (val < 0)
                        return val;

                val = lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT);
                if (val < 0)
                        return val;
                data->temp8[REMOTE2_CRIT] = val;

                val = lm90_read_reg(client, MAX6659_REG_R_REMOTE_EMERG);
                if (val < 0)
                        return val;
                data->temp8[REMOTE2_EMERG] = val;

                val = lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH);
                if (val < 0)
                        return val;
                data->temp11[REMOTE2_LOW] = val << 8;

                val = lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH);
                if (val < 0)
                        return val;
                data->temp11[REMOTE2_HIGH] = val << 8;

                lm90_select_remote_channel(data, 0);
        }

        return 0;
}

static int lm90_update_device(struct device *dev)
{
        struct lm90_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        unsigned long next_update;
        int val;

        if (!data->valid) {
                val = lm90_update_limits(dev);
                if (val < 0)
                        return val;
        }

        next_update = data->last_updated +
                      msecs_to_jiffies(data->update_interval);
        if (time_after(jiffies, next_update) || !data->valid) {
                dev_dbg(&client->dev, "Updating lm90 data.\n");

                data->valid = false;

                val = lm90_read_reg(client, LM90_REG_R_LOCAL_LOW);
                if (val < 0)
                        return val;
                data->temp8[LOCAL_LOW] = val;

                val = lm90_read_reg(client, LM90_REG_R_LOCAL_HIGH);
                if (val < 0)
                        return val;
                data->temp8[LOCAL_HIGH] = val;

                if (data->reg_local_ext) {
                        val = lm90_read16(client, LM90_REG_R_LOCAL_TEMP,
                                          data->reg_local_ext);
                        if (val < 0)
                                return val;
                        data->temp11[LOCAL_TEMP] = val;
                } else {
                        val = lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP);
                        if (val < 0)
                                return val;
                        data->temp11[LOCAL_TEMP] = val << 8;
                }
                val = lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
                                  LM90_REG_R_REMOTE_TEMPL);
                if (val < 0)
                        return val;
                data->temp11[REMOTE_TEMP] = val;

                val = lm90_read_reg(client, LM90_REG_R_STATUS);
                if (val < 0)
                        return val;
                data->alarms = val;     /* lower 8 bit of alarms */

                if (data->kind == max6696) {
                        val = lm90_select_remote_channel(data, 1);
                        if (val < 0)
                                return val;

                        val = lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
                                          LM90_REG_R_REMOTE_TEMPL);
                        if (val < 0) {
                                lm90_select_remote_channel(data, 0);
                                return val;
                        }
                        data->temp11[REMOTE2_TEMP] = val;

                        lm90_select_remote_channel(data, 0);

                        val = lm90_read_reg(client, MAX6696_REG_R_STATUS2);
                        if (val < 0)
                                return val;
                        data->alarms |= val << 8;
                }

                /*
                 * Re-enable ALERT# output if it was originally enabled and
                 * relevant alarms are all clear
                 */
                if (!(data->config_orig & 0x80) &&
                    !(data->alarms & data->alert_alarms)) {
                        if (data->config & 0x80) {
                                dev_dbg(&client->dev, "Re-enabling ALERT#\n");
                                lm90_update_confreg(data, data->config & ~0x80);
                        }
                }

                data->last_updated = jiffies;
                data->valid = true;
        }

        return 0;
}

/*
 * Conversions
 * For local temperatures and limits, critical limits and the hysteresis
 * value, the LM90 uses signed 8-bit values with LSB = 1 degree Celsius.
 * For remote temperatures and limits, it uses signed 11-bit values with
 * LSB = 0.125 degree Celsius, left-justified in 16-bit registers.  Some
 * Maxim chips use unsigned values.
 */

static inline int temp_from_s8(s8 val)
{
        return val * 1000;
}

static inline int temp_from_u8(u8 val)
{
        return val * 1000;
}

static inline int temp_from_s16(s16 val)
{
        return val / 32 * 125;
}

static inline int temp_from_u16(u16 val)
{
        return val / 32 * 125;
}

static s8 temp_to_s8(long val)
{
        if (val <= -128000)
                return -128;
        if (val >= 127000)
                return 127;
        if (val < 0)
                return (val - 500) / 1000;
        return (val + 500) / 1000;
}

static u8 temp_to_u8(long val)
{
        if (val <= 0)
                return 0;
        if (val >= 255000)
                return 255;
        return (val + 500) / 1000;
}

static s16 temp_to_s16(long val)
{
        if (val <= -128000)
                return 0x8000;
        if (val >= 127875)
                return 0x7FE0;
        if (val < 0)
                return (val - 62) / 125 * 32;
        return (val + 62) / 125 * 32;
}

static u8 hyst_to_reg(long val)
{
        if (val <= 0)
                return 0;
        if (val >= 30500)
                return 31;
        return (val + 500) / 1000;
}

/*
 * ADT7461 in compatibility mode is almost identical to LM90 except that
 * attempts to write values that are outside the range 0 < temp < 127 are
 * treated as the boundary value.
 *
 * ADT7461 in "extended mode" operation uses unsigned integers offset by
 * 64 (e.g., 0 -> -64 degC).  The range is restricted to -64..191 degC.
 */
static inline int temp_from_u8_adt7461(struct lm90_data *data, u8 val)
{
        if (data->flags & LM90_FLAG_ADT7461_EXT)
                return (val - 64) * 1000;
        return temp_from_s8(val);
}

static inline int temp_from_u16_adt7461(struct lm90_data *data, u16 val)
{
        if (data->flags & LM90_FLAG_ADT7461_EXT)
                return (val - 0x4000) / 64 * 250;
        return temp_from_s16(val);
}

static u8 temp_to_u8_adt7461(struct lm90_data *data, long val)
{
        if (data->flags & LM90_FLAG_ADT7461_EXT) {
                if (val <= -64000)
                        return 0;
                if (val >= 191000)
                        return 0xFF;
                return (val + 500 + 64000) / 1000;
        }
        if (val <= 0)
                return 0;
        if (val >= 127000)
                return 127;
        return (val + 500) / 1000;
}

static u16 temp_to_u16_adt7461(struct lm90_data *data, long val)
{
        if (data->flags & LM90_FLAG_ADT7461_EXT) {
                if (val <= -64000)
                        return 0;
                if (val >= 191750)
                        return 0xFFC0;
                return (val + 64000 + 125) / 250 * 64;
        }
        if (val <= 0)
                return 0;
        if (val >= 127750)
                return 0x7FC0;
        return (val + 125) / 250 * 64;
}

/* pec used for ADM1032 only */
static ssize_t pec_show(struct device *dev, struct device_attribute *dummy,
                        char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);

        return sprintf(buf, "%d\n", !!(client->flags & I2C_CLIENT_PEC));
}

static ssize_t pec_store(struct device *dev, struct device_attribute *dummy,
                         const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        long val;
        int err;

        err = kstrtol(buf, 10, &val);
        if (err < 0)
                return err;

        switch (val) {
        case 0:
                client->flags &= ~I2C_CLIENT_PEC;
                break;
        case 1:
                client->flags |= I2C_CLIENT_PEC;
                break;
        default:
                return -EINVAL;
        }

        return count;
}

static DEVICE_ATTR_RW(pec);

static int lm90_get_temp11(struct lm90_data *data, int index)
{
        s16 temp11 = data->temp11[index];
        int temp;

        if (data->kind == adt7461 || data->kind == tmp451)
                temp = temp_from_u16_adt7461(data, temp11);
        else if (data->kind == max6646)
                temp = temp_from_u16(temp11);
        else
                temp = temp_from_s16(temp11);

        /* +16 degrees offset for temp2 for the LM99 */
        if (data->kind == lm99 && index <= 2)
                temp += 16000;

        return temp;
}

static int lm90_set_temp11(struct lm90_data *data, int index, long val)
{
        static struct reg {
                u8 high;
                u8 low;
        } reg[] = {
        [REMOTE_LOW] = { LM90_REG_W_REMOTE_LOWH, LM90_REG_W_REMOTE_LOWL },
        [REMOTE_HIGH] = { LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL },
        [REMOTE_OFFSET] = { LM90_REG_W_REMOTE_OFFSH, LM90_REG_W_REMOTE_OFFSL },
        [REMOTE2_LOW] = { LM90_REG_W_REMOTE_LOWH, LM90_REG_W_REMOTE_LOWL },
        [REMOTE2_HIGH] = { LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL }
        };
        struct i2c_client *client = data->client;
        struct reg *regp = &reg[index];
        int err;

        /* +16 degrees offset for temp2 for the LM99 */
        if (data->kind == lm99 && index <= 2) {
                /* prevent integer underflow */
                val = max(val, -128000l);
                val -= 16000;
        }

        if (data->kind == adt7461 || data->kind == tmp451)
                data->temp11[index] = temp_to_u16_adt7461(data, val);
        else if (data->kind == max6646)
                data->temp11[index] = temp_to_u8(val) << 8;
        else if (data->flags & LM90_HAVE_REM_LIMIT_EXT)
                data->temp11[index] = temp_to_s16(val);
        else
                data->temp11[index] = temp_to_s8(val) << 8;

        lm90_select_remote_channel(data, index >= 3);
        err = i2c_smbus_write_byte_data(client, regp->high,
                                  data->temp11[index] >> 8);
        if (err < 0)
                return err;
        if (data->flags & LM90_HAVE_REM_LIMIT_EXT)
                err = i2c_smbus_write_byte_data(client, regp->low,
                                                data->temp11[index] & 0xff);

        lm90_select_remote_channel(data, 0);
        return err;
}

static int lm90_get_temp8(struct lm90_data *data, int index)
{
        s8 temp8 = data->temp8[index];
        int temp;

        if (data->kind == adt7461 || data->kind == tmp451)
                temp = temp_from_u8_adt7461(data, temp8);
        else if (data->kind == max6646)
                temp = temp_from_u8(temp8);
        else
                temp = temp_from_s8(temp8);

        /* +16 degrees offset for temp2 for the LM99 */
        if (data->kind == lm99 && index == 3)
                temp += 16000;

        return temp;
}

static int lm90_set_temp8(struct lm90_data *data, int index, long val)
{
        static const u8 reg[TEMP8_REG_NUM] = {
                LM90_REG_W_LOCAL_LOW,
                LM90_REG_W_LOCAL_HIGH,
                LM90_REG_W_LOCAL_CRIT,
                LM90_REG_W_REMOTE_CRIT,
                MAX6659_REG_W_LOCAL_EMERG,
                MAX6659_REG_W_REMOTE_EMERG,
                LM90_REG_W_REMOTE_CRIT,
                MAX6659_REG_W_REMOTE_EMERG,
        };
        struct i2c_client *client = data->client;
        int err;

        /* +16 degrees offset for temp2 for the LM99 */
        if (data->kind == lm99 && index == 3) {
                /* prevent integer underflow */
                val = max(val, -128000l);
                val -= 16000;
        }

        if (data->kind == adt7461 || data->kind == tmp451)
                data->temp8[index] = temp_to_u8_adt7461(data, val);
        else if (data->kind == max6646)
                data->temp8[index] = temp_to_u8(val);
        else
                data->temp8[index] = temp_to_s8(val);

        lm90_select_remote_channel(data, index >= 6);
        err = i2c_smbus_write_byte_data(client, reg[index], data->temp8[index]);
        lm90_select_remote_channel(data, 0);

        return err;
}

static int lm90_get_temphyst(struct lm90_data *data, int index)
{
        int temp;

        if (data->kind == adt7461 || data->kind == tmp451)
                temp = temp_from_u8_adt7461(data, data->temp8[index]);
        else if (data->kind == max6646)
                temp = temp_from_u8(data->temp8[index]);
        else
                temp = temp_from_s8(data->temp8[index]);

        /* +16 degrees offset for temp2 for the LM99 */
        if (data->kind == lm99 && index == 3)
                temp += 16000;

        return temp - temp_from_s8(data->temp_hyst);
}

static int lm90_set_temphyst(struct lm90_data *data, long val)
{
        struct i2c_client *client = data->client;
        int temp;
        int err;

        if (data->kind == adt7461 || data->kind == tmp451)
                temp = temp_from_u8_adt7461(data, data->temp8[LOCAL_CRIT]);
        else if (data->kind == max6646)
                temp = temp_from_u8(data->temp8[LOCAL_CRIT]);
        else
                temp = temp_from_s8(data->temp8[LOCAL_CRIT]);

        /* prevent integer underflow */
        val = max(val, -128000l);

        data->temp_hyst = hyst_to_reg(temp - val);
        err = i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST,
                                        data->temp_hyst);
        return err;
}

static const u8 lm90_temp_index[3] = {
        LOCAL_TEMP, REMOTE_TEMP, REMOTE2_TEMP
};

static const u8 lm90_temp_min_index[3] = {
        LOCAL_LOW, REMOTE_LOW, REMOTE2_LOW
};

static const u8 lm90_temp_max_index[3] = {
        LOCAL_HIGH, REMOTE_HIGH, REMOTE2_HIGH
};

static const u8 lm90_temp_crit_index[3] = {
        LOCAL_CRIT, REMOTE_CRIT, REMOTE2_CRIT
};

static const u8 lm90_temp_emerg_index[3] = {
        LOCAL_EMERG, REMOTE_EMERG, REMOTE2_EMERG
};

static const u8 lm90_min_alarm_bits[3] = { 5, 3, 11 };
static const u8 lm90_max_alarm_bits[3] = { 6, 4, 12 };
static const u8 lm90_crit_alarm_bits[3] = { 0, 1, 9 };
static const u8 lm90_emergency_alarm_bits[3] = { 15, 13, 14 };
static const u8 lm90_fault_bits[3] = { 0, 2, 10 };

static int lm90_temp_read(struct device *dev, u32 attr, int channel, long *val)
{
        struct lm90_data *data = dev_get_drvdata(dev);
        int err;

        mutex_lock(&data->update_lock);
        err = lm90_update_device(dev);
        mutex_unlock(&data->update_lock);
        if (err)
                return err;

        switch (attr) {
        case hwmon_temp_input:
                *val = lm90_get_temp11(data, lm90_temp_index[channel]);
                break;
        case hwmon_temp_min_alarm:
                *val = (data->alarms >> lm90_min_alarm_bits[channel]) & 1;
                break;
        case hwmon_temp_max_alarm:
                *val = (data->alarms >> lm90_max_alarm_bits[channel]) & 1;
                break;
        case hwmon_temp_crit_alarm:
                *val = (data->alarms >> lm90_crit_alarm_bits[channel]) & 1;
                break;
        case hwmon_temp_emergency_alarm:
                *val = (data->alarms >> lm90_emergency_alarm_bits[channel]) & 1;
                break;
        case hwmon_temp_fault:
                *val = (data->alarms >> lm90_fault_bits[channel]) & 1;
                break;
        case hwmon_temp_min:
                if (channel == 0)
                        *val = lm90_get_temp8(data,
                                              lm90_temp_min_index[channel]);
                else
                        *val = lm90_get_temp11(data,
                                               lm90_temp_min_index[channel]);
                break;
        case hwmon_temp_max:
                if (channel == 0)
                        *val = lm90_get_temp8(data,
                                              lm90_temp_max_index[channel]);
                else
                        *val = lm90_get_temp11(data,
                                               lm90_temp_max_index[channel]);
                break;
        case hwmon_temp_crit:
                *val = lm90_get_temp8(data, lm90_temp_crit_index[channel]);
                break;
        case hwmon_temp_crit_hyst:
                *val = lm90_get_temphyst(data, lm90_temp_crit_index[channel]);
                break;
        case hwmon_temp_emergency:
                *val = lm90_get_temp8(data, lm90_temp_emerg_index[channel]);
                break;
        case hwmon_temp_emergency_hyst:
                *val = lm90_get_temphyst(data, lm90_temp_emerg_index[channel]);
                break;
        case hwmon_temp_offset:
                *val = lm90_get_temp11(data, REMOTE_OFFSET);
                break;
        default:
                return -EOPNOTSUPP;
        }
        return 0;
}

static int lm90_temp_write(struct device *dev, u32 attr, int channel, long val)
{
        struct lm90_data *data = dev_get_drvdata(dev);
        int err;

        mutex_lock(&data->update_lock);

        err = lm90_update_device(dev);
        if (err)
                goto error;

        switch (attr) {
        case hwmon_temp_min:
                if (channel == 0)
                        err = lm90_set_temp8(data,
                                              lm90_temp_min_index[channel],
                                              val);
                else
                        err = lm90_set_temp11(data,
                                              lm90_temp_min_index[channel],
                                              val);
                break;
        case hwmon_temp_max:
                if (channel == 0)
                        err = lm90_set_temp8(data,
                                             lm90_temp_max_index[channel],
                                             val);
                else
                        err = lm90_set_temp11(data,
                                              lm90_temp_max_index[channel],
                                              val);
                break;
        case hwmon_temp_crit:
                err = lm90_set_temp8(data, lm90_temp_crit_index[channel], val);
                break;
        case hwmon_temp_crit_hyst:
                err = lm90_set_temphyst(data, val);
                break;
        case hwmon_temp_emergency:
                err = lm90_set_temp8(data, lm90_temp_emerg_index[channel], val);
                break;
        case hwmon_temp_offset:
                err = lm90_set_temp11(data, REMOTE_OFFSET, val);
                break;
        default:
                err = -EOPNOTSUPP;
                break;
        }
error:
        mutex_unlock(&data->update_lock);

        return err;
}

static umode_t lm90_temp_is_visible(const void *data, u32 attr, int channel)
{
        switch (attr) {
        case hwmon_temp_input:
        case hwmon_temp_min_alarm:
        case hwmon_temp_max_alarm:
        case hwmon_temp_crit_alarm:
        case hwmon_temp_emergency_alarm:
        case hwmon_temp_emergency_hyst:
        case hwmon_temp_fault:
                return 0444;
        case hwmon_temp_min:
        case hwmon_temp_max:
        case hwmon_temp_crit:
        case hwmon_temp_emergency:
        case hwmon_temp_offset:
                return 0644;
        case hwmon_temp_crit_hyst:
                if (channel == 0)
                        return 0644;
                return 0444;
        default:
                return 0;
        }
}

static int lm90_chip_read(struct device *dev, u32 attr, int channel, long *val)
{
        struct lm90_data *data = dev_get_drvdata(dev);
        int err;

        mutex_lock(&data->update_lock);
        err = lm90_update_device(dev);
        mutex_unlock(&data->update_lock);
        if (err)
                return err;

        switch (attr) {
        case hwmon_chip_update_interval:
                *val = data->update_interval;
                break;
        case hwmon_chip_alarms:
                *val = data->alarms;
                break;
        default:
                return -EOPNOTSUPP;
        }

        return 0;
}

static int lm90_chip_write(struct device *dev, u32 attr, int channel, long val)
{
        struct lm90_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        int err;

        mutex_lock(&data->update_lock);

        err = lm90_update_device(dev);
        if (err)
                goto error;

        switch (attr) {
        case hwmon_chip_update_interval:
                err = lm90_set_convrate(client, data,
                                        clamp_val(val, 0, 100000));
                break;
        default:
                err = -EOPNOTSUPP;
                break;
        }
error:
        mutex_unlock(&data->update_lock);

        return err;
}

static umode_t lm90_chip_is_visible(const void *data, u32 attr, int channel)
{
        switch (attr) {
        case hwmon_chip_update_interval:
                return 0644;
        case hwmon_chip_alarms:
                return 0444;
        default:
                return 0;
        }
}

static int lm90_read(struct device *dev, enum hwmon_sensor_types type,
                     u32 attr, int channel, long *val)
{
        switch (type) {
        case hwmon_chip:
                return lm90_chip_read(dev, attr, channel, val);
        case hwmon_temp:
                return lm90_temp_read(dev, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int lm90_write(struct device *dev, enum hwmon_sensor_types type,
                      u32 attr, int channel, long val)
{
        switch (type) {
        case hwmon_chip:
                return lm90_chip_write(dev, attr, channel, val);
        case hwmon_temp:
                return lm90_temp_write(dev, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t lm90_is_visible(const void *data, enum hwmon_sensor_types type,
                               u32 attr, int channel)
{
        switch (type) {
        case hwmon_chip:
                return lm90_chip_is_visible(data, attr, channel);
        case hwmon_temp:
                return lm90_temp_is_visible(data, attr, channel);
        default:
                return 0;
        }
}

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm90_detect(struct i2c_client *client,
                       struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = client->adapter;
        int address = client->addr;
        const char *name = NULL;
        int man_id, chip_id, config1, config2, convrate;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                return -ENODEV;

        /* detection and identification */
        man_id = i2c_smbus_read_byte_data(client, LM90_REG_R_MAN_ID);
        chip_id = i2c_smbus_read_byte_data(client, LM90_REG_R_CHIP_ID);
        config1 = i2c_smbus_read_byte_data(client, LM90_REG_R_CONFIG1);
        convrate = i2c_smbus_read_byte_data(client, LM90_REG_R_CONVRATE);
        if (man_id < 0 || chip_id < 0 || config1 < 0 || convrate < 0)
                return -ENODEV;

        if (man_id == 0x01 || man_id == 0x5C || man_id == 0x41) {
                config2 = i2c_smbus_read_byte_data(client, LM90_REG_R_CONFIG2);
                if (config2 < 0)
                        return -ENODEV;
        } else
                config2 = 0;            /* Make compiler happy */

        if ((address == 0x4C || address == 0x4D)
         && man_id == 0x01) { /* National Semiconductor */
                if ((config1 & 0x2A) == 0x00
                 && (config2 & 0xF8) == 0x00
                 && convrate <= 0x09) {
                        if (address == 0x4C
                         && (chip_id & 0xF0) == 0x20) { /* LM90 */
                                name = "lm90";
                        } else
                        if ((chip_id & 0xF0) == 0x30) { /* LM89/LM99 */
                                name = "lm99";
                                dev_info(&adapter->dev,
                                         "Assuming LM99 chip at 0x%02x\n",
                                         address);
                                dev_info(&adapter->dev,
                                         "If it is an LM89, instantiate it "
                                         "with the new_device sysfs "
                                         "interface\n");
                        } else
                        if (address == 0x4C
                         && (chip_id & 0xF0) == 0x10) { /* LM86 */
                                name = "lm86";
                        }
                }
        } else
        if ((address == 0x4C || address == 0x4D)
         && man_id == 0x41) { /* Analog Devices */
                if ((chip_id & 0xF0) == 0x40 /* ADM1032 */
                 && (config1 & 0x3F) == 0x00
                 && convrate <= 0x0A) {
                        name = "adm1032";
                        /*
                         * The ADM1032 supports PEC, but only if combined
                         * transactions are not used.
                         */
                        if (i2c_check_functionality(adapter,
                                                    I2C_FUNC_SMBUS_BYTE))
                                info->flags |= I2C_CLIENT_PEC;
                } else
                if (chip_id == 0x51 /* ADT7461 */
                 && (config1 & 0x1B) == 0x00
                 && convrate <= 0x0A) {
                        name = "adt7461";
                } else
                if (chip_id == 0x57 /* ADT7461A, NCT1008 */
                 && (config1 & 0x1B) == 0x00
                 && convrate <= 0x0A) {
                        name = "adt7461a";
                }
        } else
        if (man_id == 0x4D) { /* Maxim */
                int emerg, emerg2, status2;

                /*
                 * We read MAX6659_REG_R_REMOTE_EMERG twice, and re-read
                 * LM90_REG_R_MAN_ID in between. If MAX6659_REG_R_REMOTE_EMERG
                 * exists, both readings will reflect the same value. Otherwise,
                 * the readings will be different.
                 */
                emerg = i2c_smbus_read_byte_data(client,
                                                 MAX6659_REG_R_REMOTE_EMERG);
                man_id = i2c_smbus_read_byte_data(client,
                                                  LM90_REG_R_MAN_ID);
                emerg2 = i2c_smbus_read_byte_data(client,
                                                  MAX6659_REG_R_REMOTE_EMERG);
                status2 = i2c_smbus_read_byte_data(client,
                                                   MAX6696_REG_R_STATUS2);
                if (emerg < 0 || man_id < 0 || emerg2 < 0 || status2 < 0)
                        return -ENODEV;

                /*
                 * The MAX6657, MAX6658 and MAX6659 do NOT have a chip_id
                 * register. Reading from that address will return the last
                 * read value, which in our case is those of the man_id
                 * register. Likewise, the config1 register seems to lack a
                 * low nibble, so the value will be those of the previous
                 * read, so in our case those of the man_id register.
                 * MAX6659 has a third set of upper temperature limit registers.
                 * Those registers also return values on MAX6657 and MAX6658,
                 * thus the only way to detect MAX6659 is by its address.
                 * For this reason it will be mis-detected as MAX6657 if its
                 * address is 0x4C.
                 */
                if (chip_id == man_id
                 && (address == 0x4C || address == 0x4D || address == 0x4E)
                 && (config1 & 0x1F) == (man_id & 0x0F)
                 && convrate <= 0x09) {
                        if (address == 0x4C)
                                name = "max6657";
                        else
                                name = "max6659";
                } else
                /*
                 * Even though MAX6695 and MAX6696 do not have a chip ID
                 * register, reading it returns 0x01. Bit 4 of the config1
                 * register is unused and should return zero when read. Bit 0 of
                 * the status2 register is unused and should return zero when
                 * read.
                 *
                 * MAX6695 and MAX6696 have an additional set of temperature
                 * limit registers. We can detect those chips by checking if
                 * one of those registers exists.
                 */
                if (chip_id == 0x01
                 && (config1 & 0x10) == 0x00
                 && (status2 & 0x01) == 0x00
                 && emerg == emerg2
                 && convrate <= 0x07) {
                        name = "max6696";
                } else
                /*
                 * The chip_id register of the MAX6680 and MAX6681 holds the
                 * revision of the chip. The lowest bit of the config1 register
                 * is unused and should return zero when read, so should the
                 * second to last bit of config1 (software reset).
                 */
                if (chip_id == 0x01
                 && (config1 & 0x03) == 0x00
                 && convrate <= 0x07) {
                        name = "max6680";
                } else
                /*
                 * The chip_id register of the MAX6646/6647/6649 holds the
                 * revision of the chip. The lowest 6 bits of the config1
                 * register are unused and should return zero when read.
                 */
                if (chip_id == 0x59
                 && (config1 & 0x3f) == 0x00
                 && convrate <= 0x07) {
                        name = "max6646";
                } else
                /*
                 * The chip_id of the MAX6654 holds the revision of the chip.
                 * The lowest 3 bits of the config1 register are unused and
                 * should return zero when read.
                 */
                if (chip_id == 0x08
                 && (config1 & 0x07) == 0x00
                 && convrate <= 0x07) {
                        name = "max6654";
                }
        } else
        if (address == 0x4C
         && man_id == 0x5C) { /* Winbond/Nuvoton */
                if ((config1 & 0x2A) == 0x00
                 && (config2 & 0xF8) == 0x00) {
                        if (chip_id == 0x01 /* W83L771W/G */
                         && convrate <= 0x09) {
                                name = "w83l771";
                        } else
                        if ((chip_id & 0xFE) == 0x10 /* W83L771AWG/ASG */
                         && convrate <= 0x08) {
                                name = "w83l771";
                        }
                }
        } else
        if (address >= 0x48 && address <= 0x4F
         && man_id == 0xA1) { /*  NXP Semiconductor/Philips */
                if (chip_id == 0x00
                 && (config1 & 0x2A) == 0x00
                 && (config2 & 0xFE) == 0x00
                 && convrate <= 0x09) {
                        name = "sa56004";
                }
        } else
        if ((address == 0x4C || address == 0x4D)
         && man_id == 0x47) { /* GMT */
                if (chip_id == 0x01 /* G781 */
                 && (config1 & 0x3F) == 0x00
                 && convrate <= 0x08)
                        name = "g781";
        } else
        if (address == 0x4C
         && man_id == 0x55) { /* Texas Instruments */
                int local_ext;

                local_ext = i2c_smbus_read_byte_data(client,
                                                     TMP451_REG_R_LOCAL_TEMPL);

                if (chip_id == 0x00 /* TMP451 */
                 && (config1 & 0x1B) == 0x00
                 && convrate <= 0x09
                 && (local_ext & 0x0F) == 0x00)
                        name = "tmp451";
        }

        if (!name) { /* identification failed */
                dev_dbg(&adapter->dev,
                        "Unsupported chip at 0x%02x (man_id=0x%02X, "
                        "chip_id=0x%02X)\n", address, man_id, chip_id);
                return -ENODEV;
        }

        strlcpy(info->type, name, I2C_NAME_SIZE);

        return 0;
}

static void lm90_restore_conf(void *_data)
{
        struct lm90_data *data = _data;
        struct i2c_client *client = data->client;

        /* Restore initial configuration */
        lm90_write_convrate(data, data->convrate_orig);
        i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
                                  data->config_orig);
}

static int lm90_init_client(struct i2c_client *client, struct lm90_data *data)
{
        int config, convrate;

        convrate = lm90_read_reg(client, LM90_REG_R_CONVRATE);
        if (convrate < 0)
                return convrate;
        data->convrate_orig = convrate;

        /*
         * Start the conversions.
         */
        config = lm90_read_reg(client, LM90_REG_R_CONFIG1);
        if (config < 0)
                return config;
        data->config_orig = config;
        data->config = config;

        lm90_set_convrate(client, data, 500); /* 500ms; 2Hz conversion rate */

        /* Check Temperature Range Select */
        if (data->kind == adt7461 || data->kind == tmp451) {
                if (config & 0x04)
                        data->flags |= LM90_FLAG_ADT7461_EXT;
        }

        /*
         * Put MAX6680/MAX8881 into extended resolution (bit 0x10,
         * 0.125 degree resolution) and range (0x08, extend range
         * to -64 degree) mode for the remote temperature sensor.
         */
        if (data->kind == max6680)
                config |= 0x18;

        /*
         * Put MAX6654 into extended range (0x20, extend minimum range from
         * 0 degrees to -64 degrees). Note that extended resolution is not
         * possible on the MAX6654 unless conversion rate is set to 1 Hz or
         * slower, which is intentionally not done by default.
         */
        if (data->kind == max6654)
                config |= 0x20;

        /*
         * Select external channel 0 for max6695/96
         */
        if (data->kind == max6696)
                config &= ~0x08;

        /*
         * Interrupt is enabled by default on reset, but it may be disabled
         * by bootloader, unmask it.
         */
        if (client->irq)
                config &= ~0x80;

        config &= 0xBF; /* run */
        lm90_update_confreg(data, config);

        return devm_add_action_or_reset(&client->dev, lm90_restore_conf, data);
}

static bool lm90_is_tripped(struct i2c_client *client, u16 *status)
{
        struct lm90_data *data = i2c_get_clientdata(client);
        int st, st2 = 0;

        st = lm90_read_reg(client, LM90_REG_R_STATUS);
        if (st < 0)
                return false;

        if (data->kind == max6696) {
                st2 = lm90_read_reg(client, MAX6696_REG_R_STATUS2);
                if (st2 < 0)
                        return false;
        }

        *status = st | (st2 << 8);

        if ((st & 0x7f) == 0 && (st2 & 0xfe) == 0)
                return false;

        if ((st & (LM90_STATUS_LLOW | LM90_STATUS_LHIGH | LM90_STATUS_LTHRM)) ||
            (st2 & MAX6696_STATUS2_LOT2))
                dev_dbg(&client->dev,
                        "temp%d out of range, please check!\n", 1);
        if ((st & (LM90_STATUS_RLOW | LM90_STATUS_RHIGH | LM90_STATUS_RTHRM)) ||
            (st2 & MAX6696_STATUS2_ROT2))
                dev_dbg(&client->dev,
                        "temp%d out of range, please check!\n", 2);
        if (st & LM90_STATUS_ROPEN)
                dev_dbg(&client->dev,
                        "temp%d diode open, please check!\n", 2);
        if (st2 & (MAX6696_STATUS2_R2LOW | MAX6696_STATUS2_R2HIGH |
                   MAX6696_STATUS2_R2THRM | MAX6696_STATUS2_R2OT2))
                dev_dbg(&client->dev,
                        "temp%d out of range, please check!\n", 3);
        if (st2 & MAX6696_STATUS2_R2OPEN)
                dev_dbg(&client->dev,
                        "temp%d diode open, please check!\n", 3);

        if (st & LM90_STATUS_LLOW)
                hwmon_notify_event(data->hwmon_dev, hwmon_temp,
                                   hwmon_temp_min, 0);
        if (st & LM90_STATUS_RLOW)
                hwmon_notify_event(data->hwmon_dev, hwmon_temp,
                                   hwmon_temp_min, 1);
        if (st2 & MAX6696_STATUS2_R2LOW)
                hwmon_notify_event(data->hwmon_dev, hwmon_temp,
                                   hwmon_temp_min, 2);
        if (st & LM90_STATUS_LHIGH)
                hwmon_notify_event(data->hwmon_dev, hwmon_temp,
                                   hwmon_temp_max, 0);
        if (st & LM90_STATUS_RHIGH)
                hwmon_notify_event(data->hwmon_dev, hwmon_temp,
                                   hwmon_temp_max, 1);
        if (st2 & MAX6696_STATUS2_R2HIGH)
                hwmon_notify_event(data->hwmon_dev, hwmon_temp,
                                   hwmon_temp_max, 2);

        return true;
}

static irqreturn_t lm90_irq_thread(int irq, void *dev_id)
{
        struct i2c_client *client = dev_id;
        u16 status;

        if (lm90_is_tripped(client, &status))
                return IRQ_HANDLED;
        else
                return IRQ_NONE;
}

static void lm90_remove_pec(void *dev)
{
        device_remove_file(dev, &dev_attr_pec);
}

static void lm90_regulator_disable(void *regulator)
{
        regulator_disable(regulator);
}


static const struct hwmon_ops lm90_ops = {
        .is_visible = lm90_is_visible,
        .read = lm90_read,
        .write = lm90_write,
};

static int lm90_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct i2c_adapter *adapter = client->adapter;
        struct hwmon_channel_info *info;
        struct regulator *regulator;
        struct device *hwmon_dev;
        struct lm90_data *data;
        int err;

        regulator = devm_regulator_get(dev, "vcc");
        if (IS_ERR(regulator))
                return PTR_ERR(regulator);

        err = regulator_enable(regulator);
        if (err < 0) {
                dev_err(dev, "Failed to enable regulator: %d\n", err);
                return err;
        }

        err = devm_add_action_or_reset(dev, lm90_regulator_disable, regulator);
        if (err)
                return err;

        data = devm_kzalloc(dev, sizeof(struct lm90_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->client = client;
        i2c_set_clientdata(client, data);
        mutex_init(&data->update_lock);

        /* Set the device type */
        if (client->dev.of_node)
                data->kind = (enum chips)of_device_get_match_data(&client->dev);
        else
                data->kind = i2c_match_id(lm90_id, client)->driver_data;
        if (data->kind == adm1032) {
                if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
                        client->flags &= ~I2C_CLIENT_PEC;
        }

        /*
         * Different devices have different alarm bits triggering the
         * ALERT# output
         */
        data->alert_alarms = lm90_params[data->kind].alert_alarms;

        /* Set chip capabilities */
        data->flags = lm90_params[data->kind].flags;

        data->chip.ops = &lm90_ops;
        data->chip.info = data->info;

        data->info[0] = HWMON_CHANNEL_INFO(chip,
                HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL | HWMON_C_ALARMS);
        data->info[1] = &data->temp_info;

        info = &data->temp_info;
        info->type = hwmon_temp;
        info->config = data->channel_config;

        data->channel_config[0] = HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
                HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MIN_ALARM |
                HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM;
        data->channel_config[1] = HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
                HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MIN_ALARM |
                HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM | HWMON_T_FAULT;

        if (data->flags & LM90_HAVE_OFFSET)
                data->channel_config[1] |= HWMON_T_OFFSET;

        if (data->flags & LM90_HAVE_EMERGENCY) {
                data->channel_config[0] |= HWMON_T_EMERGENCY |
                        HWMON_T_EMERGENCY_HYST;
                data->channel_config[1] |= HWMON_T_EMERGENCY |
                        HWMON_T_EMERGENCY_HYST;
        }

        if (data->flags & LM90_HAVE_EMERGENCY_ALARM) {
                data->channel_config[0] |= HWMON_T_EMERGENCY_ALARM;
                data->channel_config[1] |= HWMON_T_EMERGENCY_ALARM;
        }

        if (data->flags & LM90_HAVE_TEMP3) {
                data->channel_config[2] = HWMON_T_INPUT |
                        HWMON_T_MIN | HWMON_T_MAX |
                        HWMON_T_CRIT | HWMON_T_CRIT_HYST |
                        HWMON_T_EMERGENCY | HWMON_T_EMERGENCY_HYST |
                        HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
                        HWMON_T_CRIT_ALARM | HWMON_T_EMERGENCY_ALARM |
                        HWMON_T_FAULT;
        }

        data->reg_local_ext = lm90_params[data->kind].reg_local_ext;

        /* Set maximum conversion rate */
        data->max_convrate = lm90_params[data->kind].max_convrate;

        /* Initialize the LM90 chip */
        err = lm90_init_client(client, data);
        if (err < 0) {
                dev_err(dev, "Failed to initialize device\n");
                return err;
        }

        /*
         * The 'pec' attribute is attached to the i2c device and thus created
         * separately.
         */
        if (client->flags & I2C_CLIENT_PEC) {
                err = device_create_file(dev, &dev_attr_pec);
                if (err)
                        return err;
                err = devm_add_action_or_reset(dev, lm90_remove_pec, dev);
                if (err)
                        return err;
        }

        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
                                                         data, &data->chip,
                                                         NULL);
        if (IS_ERR(hwmon_dev))
                return PTR_ERR(hwmon_dev);

        data->hwmon_dev = hwmon_dev;

        if (client->irq) {
                dev_dbg(dev, "IRQ: %d\n", client->irq);
                err = devm_request_threaded_irq(dev, client->irq,
                                                NULL, lm90_irq_thread,
                                                IRQF_ONESHOT, "lm90", client);
                if (err < 0) {
                        dev_err(dev, "cannot request IRQ %d\n", client->irq);
                        return err;
                }
        }

        return 0;
}

static void lm90_alert(struct i2c_client *client, enum i2c_alert_protocol type,
                       unsigned int flag)
{
        u16 alarms;

        if (type != I2C_PROTOCOL_SMBUS_ALERT)
                return;

        if (lm90_is_tripped(client, &alarms)) {
                /*
                 * Disable ALERT# output, because these chips don't implement
                 * SMBus alert correctly; they should only hold the alert line
                 * low briefly.
                 */
                struct lm90_data *data = i2c_get_clientdata(client);

                if ((data->flags & LM90_HAVE_BROKEN_ALERT) &&
                    (alarms & data->alert_alarms)) {
                        dev_dbg(&client->dev, "Disabling ALERT#\n");
                        lm90_update_confreg(data, data->config | 0x80);
                }
        } else {
                dev_dbg(&client->dev, "Everything OK\n");
        }
}

static int __maybe_unused lm90_suspend(struct device *dev)
{
        struct lm90_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;

        if (client->irq)
                disable_irq(client->irq);

        return 0;
}

static int __maybe_unused lm90_resume(struct device *dev)
{
        struct lm90_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;

        if (client->irq)
                enable_irq(client->irq);

        return 0;
}

static SIMPLE_DEV_PM_OPS(lm90_pm_ops, lm90_suspend, lm90_resume);

static struct i2c_driver lm90_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "lm90",
                .of_match_table = of_match_ptr(lm90_of_match),
                .pm     = &lm90_pm_ops,
        },
        .probe_new      = lm90_probe,
        .alert          = lm90_alert,
        .id_table       = lm90_id,
        .detect         = lm90_detect,
        .address_list   = normal_i2c,
};

module_i2c_driver(lm90_driver);

MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
MODULE_DESCRIPTION("LM90/ADM1032 driver");
MODULE_LICENSE("GPL");