// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * dell-smm-hwmon.c -- Linux driver for accessing the SMM BIOS on Dell laptops.
 *
 * Copyright (C) 2001  Massimo Dal Zotto <dz@debian.org>
 *
 * Hwmon integration:
 * Copyright (C) 2011  Jean Delvare <jdelvare@suse.de>
 * Copyright (C) 2013, 2014  Guenter Roeck <linux@roeck-us.net>
 * Copyright (C) 2014, 2015  Pali Rohár <pali@kernel.org>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/acpi.h>
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/hwmon.h>
#include <linux/init.h>
#include <linux/kconfig.h>
#include <linux/kernel.h>
#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/string.h>
#include <linux/thermal.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/wmi.h>

#include <linux/i8k.h>
#include <linux/unaligned.h>

#define I8K_SMM_FN_STATUS       0x0025
#define I8K_SMM_POWER_STATUS    0x0069
#define I8K_SMM_SET_FAN         0x01a3
#define I8K_SMM_GET_FAN         0x00a3
#define I8K_SMM_GET_SPEED       0x02a3
#define I8K_SMM_GET_FAN_TYPE    0x03a3
#define I8K_SMM_GET_NOM_SPEED   0x04a3
#define I8K_SMM_GET_TEMP        0x10a3
#define I8K_SMM_GET_TEMP_TYPE   0x11a3
#define I8K_SMM_GET_DELL_SIG1   0xfea3
#define I8K_SMM_GET_DELL_SIG2   0xffa3

/* in usecs */
#define DELL_SMM_MAX_DURATION  250000

#define I8K_FAN_MULT            30
#define I8K_FAN_RPM_THRESHOLD   1000
#define I8K_MAX_TEMP            127

#define I8K_FN_NONE             0x00
#define I8K_FN_UP               0x01
#define I8K_FN_DOWN             0x02
#define I8K_FN_MUTE             0x04
#define I8K_FN_MASK             0x07
#define I8K_FN_SHIFT            8

#define I8K_POWER_AC            0x05
#define I8K_POWER_BATTERY       0x01

#define DELL_SMM_WMI_GUID       "F1DDEE52-063C-4784-A11E-8A06684B9B01"
#define DELL_SMM_LEGACY_EXECUTE 0x1

#define DELL_SMM_NO_TEMP        10
#define DELL_SMM_NO_FANS        4

/* limit fan multiplier to avoid overflow */
#define DELL_SMM_MAX_FAN_MULT (INT_MAX / U16_MAX)

struct smm_regs {
        unsigned int eax;
        unsigned int ebx;
        unsigned int ecx;
        unsigned int edx;
        unsigned int esi;
        unsigned int edi;
};

struct dell_smm_ops {
        struct device *smm_dev;
        int (*smm_call)(struct device *smm_dev, struct smm_regs *regs);
};

struct dell_smm_data {
        struct mutex i8k_mutex; /* lock for sensors writes */
        char bios_version[4];
        char bios_machineid[16];
        uint i8k_fan_mult;
        uint i8k_pwm_mult;
        uint i8k_fan_max;
        int temp_type[DELL_SMM_NO_TEMP];
        bool fan[DELL_SMM_NO_FANS];
        int fan_type[DELL_SMM_NO_FANS];
        int *fan_nominal_speed[DELL_SMM_NO_FANS];
        const struct dell_smm_ops *ops;
};

struct dell_smm_cooling_data {
        u8 fan_num;
        struct dell_smm_data *data;
};

MODULE_AUTHOR("Massimo Dal Zotto <dz@debian.org>");
MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
MODULE_DESCRIPTION("Dell laptop SMM BIOS hwmon driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("i8k");

static bool force;
module_param_unsafe(force, bool, 0);
MODULE_PARM_DESC(force, "Force loading without checking for supported models and features");

static bool ignore_dmi;
module_param(ignore_dmi, bool, 0);
MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");

#if IS_ENABLED(CONFIG_I8K)
static bool restricted = true;
module_param(restricted, bool, 0);
MODULE_PARM_DESC(restricted, "Restrict fan control and serial number to CAP_SYS_ADMIN (default: 1)");

static bool power_status;
module_param(power_status, bool, 0600);
MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k (default: 0)");
#endif

static uint fan_mult;
module_param(fan_mult, uint, 0);
MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with (default: autodetect)");

static uint fan_max;
module_param(fan_max, uint, 0);
MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed (default: autodetect)");

static bool disallow_fan_type_call, disallow_fan_support;

static unsigned int manual_fan, auto_fan;

static const char * const temp_labels[] = {
        "CPU",
        "GPU",
        "SODIMM",
        "Other",
        "Ambient",
        "Other",
};

static const char * const fan_labels[] = {
        "Processor Fan",
        "Motherboard Fan",
        "Video Fan",
        "Power Supply Fan",
        "Chipset Fan",
        "Other Fan",
};

static const char * const docking_labels[] = {
        "Docking Processor Fan",
        "Docking Motherboard Fan",
        "Docking Video Fan",
        "Docking Power Supply Fan",
        "Docking Chipset Fan",
        "Docking Other Fan",
};

static inline const char __init *i8k_get_dmi_data(int field)
{
        const char *dmi_data = dmi_get_system_info(field);

        return dmi_data && *dmi_data ? dmi_data : "?";
}

/*
 * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
 */
static int i8k_smm_func(void *par)
{
        struct smm_regs *regs = par;
        unsigned char carry;

        /* SMM requires CPU 0 */
        if (smp_processor_id() != 0)
                return -EBUSY;

        asm volatile("out %%al,$0xb2\n\t"
                     "out %%al,$0x84\n\t"
                     "setc %0\n"
                     : "=mr" (carry),
                       "+a" (regs->eax),
                       "+b" (regs->ebx),
                       "+c" (regs->ecx),
                       "+d" (regs->edx),
                       "+S" (regs->esi),
                       "+D" (regs->edi));

        if (carry)
                return -EINVAL;

        return 0;
}

/*
 * Call the System Management Mode BIOS.
 */
static int i8k_smm_call(struct device *dummy, struct smm_regs *regs)
{
        int ret;

        cpus_read_lock();
        ret = smp_call_on_cpu(0, i8k_smm_func, regs, true);
        cpus_read_unlock();

        return ret;
}

static const struct dell_smm_ops i8k_smm_ops = {
        .smm_call = i8k_smm_call,
};

/*
 * Call the System Management Mode BIOS over WMI.
 */
static ssize_t wmi_parse_register(u8 *buffer, u32 length, unsigned int *reg)
{
        __le32 value;
        u32 reg_size;

        if (length <= sizeof(reg_size))
                return -ENODATA;

        reg_size = get_unaligned_le32(buffer);
        if (!reg_size || reg_size > sizeof(value))
                return -ENOMSG;

        if (length < sizeof(reg_size) + reg_size)
                return -ENODATA;

        memcpy_and_pad(&value, sizeof(value), buffer + sizeof(reg_size), reg_size, 0);
        *reg = le32_to_cpu(value);

        return reg_size + sizeof(reg_size);
}

static int wmi_parse_response(u8 *buffer, u32 length, struct smm_regs *regs)
{
        unsigned int *registers[] = {
                &regs->eax,
                &regs->ebx,
                &regs->ecx,
                &regs->edx
        };
        u32 offset = 0;
        ssize_t ret;
        int i;

        for (i = 0; i < ARRAY_SIZE(registers); i++) {
                if (offset >= length)
                        return -ENODATA;

                ret = wmi_parse_register(buffer + offset, length - offset, registers[i]);
                if (ret < 0)
                        return ret;

                offset += ret;
        }

        if (offset != length)
                return -ENOMSG;

        return 0;
}

static int wmi_smm_call(struct device *dev, struct smm_regs *regs)
{
        struct wmi_device *wdev = container_of(dev, struct wmi_device, dev);
        struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
        u32 wmi_payload[] = {
                sizeof(regs->eax),
                regs->eax,
                sizeof(regs->ebx),
                regs->ebx,
                sizeof(regs->ecx),
                regs->ecx,
                sizeof(regs->edx),
                regs->edx
        };
        const struct acpi_buffer in = {
                .length = sizeof(wmi_payload),
                .pointer = &wmi_payload,
        };
        union acpi_object *obj;
        acpi_status status;
        int ret;

        status = wmidev_evaluate_method(wdev, 0x0, DELL_SMM_LEGACY_EXECUTE, &in, &out);
        if (ACPI_FAILURE(status))
                return -EIO;

        obj = out.pointer;
        if (!obj)
                return -ENODATA;

        if (obj->type != ACPI_TYPE_BUFFER) {
                ret = -ENOMSG;

                goto err_free;
        }

        ret = wmi_parse_response(obj->buffer.pointer, obj->buffer.length, regs);

err_free:
        kfree(obj);

        return ret;
}

static int dell_smm_call(const struct dell_smm_ops *ops, struct smm_regs *regs)
{
        unsigned int eax = regs->eax;
        unsigned int ebx = regs->ebx;
        long long duration;
        ktime_t calltime;
        int ret;

        calltime = ktime_get();
        ret = ops->smm_call(ops->smm_dev, regs);
        duration = ktime_us_delta(ktime_get(), calltime);

        pr_debug("SMM(0x%.4x 0x%.4x) = 0x%.4x status: %d (took %7lld usecs)\n",
                 eax, ebx, regs->eax & 0xffff, ret, duration);

        if (duration > DELL_SMM_MAX_DURATION)
                pr_warn_once("SMM call took %lld usecs!\n", duration);

        if (ret < 0)
                return ret;

        if ((regs->eax & 0xffff) == 0xffff || regs->eax == eax)
                return -EINVAL;

        return 0;
}

/*
 * Read the fan status.
 */
static int i8k_get_fan_status(const struct dell_smm_data *data, u8 fan)
{
        struct smm_regs regs = {
                .eax = I8K_SMM_GET_FAN,
                .ebx = fan,
        };

        if (disallow_fan_support)
                return -EINVAL;

        return dell_smm_call(data->ops, &regs) ? : regs.eax & 0xff;
}

/*
 * Read the fan speed in RPM.
 */
static int i8k_get_fan_speed(const struct dell_smm_data *data, u8 fan)
{
        struct smm_regs regs = {
                .eax = I8K_SMM_GET_SPEED,
                .ebx = fan,
        };

        if (disallow_fan_support)
                return -EINVAL;

        return dell_smm_call(data->ops, &regs) ? : (regs.eax & 0xffff) * data->i8k_fan_mult;
}

/*
 * Read the fan type.
 */
static int _i8k_get_fan_type(const struct dell_smm_data *data, u8 fan)
{
        struct smm_regs regs = {
                .eax = I8K_SMM_GET_FAN_TYPE,
                .ebx = fan,
        };

        if (disallow_fan_support || disallow_fan_type_call)
                return -EINVAL;

        return dell_smm_call(data->ops, &regs) ? : regs.eax & 0xff;
}

static int i8k_get_fan_type(struct dell_smm_data *data, u8 fan)
{
        /* I8K_SMM_GET_FAN_TYPE SMM call is expensive, so cache values */
        if (data->fan_type[fan] == INT_MIN)
                data->fan_type[fan] = _i8k_get_fan_type(data, fan);

        return data->fan_type[fan];
}

/*
 * Read the fan nominal rpm for specific fan speed.
 */
static int i8k_get_fan_nominal_speed(const struct dell_smm_data *data, u8 fan, int speed)
{
        struct smm_regs regs = {
                .eax = I8K_SMM_GET_NOM_SPEED,
                .ebx = fan | (speed << 8),
        };

        if (disallow_fan_support)
                return -EINVAL;

        return dell_smm_call(data->ops, &regs) ? : (regs.eax & 0xffff);
}

/*
 * Enable or disable automatic BIOS fan control support
 */
static int i8k_enable_fan_auto_mode(const struct dell_smm_data *data, bool enable)
{
        struct smm_regs regs = { };

        if (disallow_fan_support)
                return -EINVAL;

        regs.eax = enable ? auto_fan : manual_fan;
        return dell_smm_call(data->ops, &regs);
}

/*
 * Set the fan speed (off, low, high, ...).
 */
static int i8k_set_fan(const struct dell_smm_data *data, u8 fan, int speed)
{
        struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };

        if (disallow_fan_support)
                return -EINVAL;

        regs.ebx = fan | (speed << 8);

        return dell_smm_call(data->ops, &regs);
}

static int i8k_get_temp_type(const struct dell_smm_data *data, u8 sensor)
{
        struct smm_regs regs = {
                .eax = I8K_SMM_GET_TEMP_TYPE,
                .ebx = sensor,
        };

        return dell_smm_call(data->ops, &regs) ? : regs.eax & 0xff;
}

/*
 * Read the cpu temperature.
 */
static int _i8k_get_temp(const struct dell_smm_data *data, u8 sensor)
{
        struct smm_regs regs = {
                .eax = I8K_SMM_GET_TEMP,
                .ebx = sensor,
        };

        return dell_smm_call(data->ops, &regs) ? : regs.eax & 0xff;
}

static int i8k_get_temp(const struct dell_smm_data *data, u8 sensor)
{
        int temp = _i8k_get_temp(data, sensor);

        /*
         * Sometimes the temperature sensor returns 0x99, which is out of range.
         * In this case we retry (once) before returning an error.
         # 1003655137 00000058 00005a4b
         # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
         # 1003655139 00000054 00005c52
         */
        if (temp == 0x99) {
                msleep(100);
                temp = _i8k_get_temp(data, sensor);
        }
        /*
         * Return -ENODATA for all invalid temperatures.
         *
         * Known instances are the 0x99 value as seen above as well as
         * 0xc1 (193), which may be returned when trying to read the GPU
         * temperature if the system supports a GPU and it is currently
         * turned off.
         */
        if (temp > I8K_MAX_TEMP)
                return -ENODATA;

        return temp;
}

static int dell_smm_get_signature(const struct dell_smm_ops *ops, int req_fn)
{
        struct smm_regs regs = { .eax = req_fn, };
        int rc;

        rc = dell_smm_call(ops, &regs);
        if (rc < 0)
                return rc;

        return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
}

#if IS_ENABLED(CONFIG_I8K)

/*
 * Read the Fn key status.
 */
static int i8k_get_fn_status(const struct dell_smm_data *data)
{
        struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
        int rc;

        rc = dell_smm_call(data->ops, &regs);
        if (rc < 0)
                return rc;

        switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
        case I8K_FN_UP:
                return I8K_VOL_UP;
        case I8K_FN_DOWN:
                return I8K_VOL_DOWN;
        case I8K_FN_MUTE:
                return I8K_VOL_MUTE;
        default:
                return 0;
        }
}

/*
 * Read the power status.
 */
static int i8k_get_power_status(const struct dell_smm_data *data)
{
        struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
        int rc;

        rc = dell_smm_call(data->ops, &regs);
        if (rc < 0)
                return rc;

        return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
}

/*
 * Procfs interface
 */

static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
{
        struct dell_smm_data *data = pde_data(file_inode(fp));
        int __user *argp = (int __user *)arg;
        int speed, err;
        int val = 0;

        if (!argp)
                return -EINVAL;

        switch (cmd) {
        case I8K_BIOS_VERSION:
                if (!isdigit(data->bios_version[0]) || !isdigit(data->bios_version[1]) ||
                    !isdigit(data->bios_version[2]))
                        return -EINVAL;

                val = (data->bios_version[0] << 16) |
                                (data->bios_version[1] << 8) | data->bios_version[2];

                if (copy_to_user(argp, &val, sizeof(val)))
                        return -EFAULT;

                return 0;
        case I8K_MACHINE_ID:
                if (restricted && !capable(CAP_SYS_ADMIN))
                        return -EPERM;

                if (copy_to_user(argp, data->bios_machineid, sizeof(data->bios_machineid)))
                        return -EFAULT;

                return 0;
        case I8K_FN_STATUS:
                val = i8k_get_fn_status(data);
                break;

        case I8K_POWER_STATUS:
                val = i8k_get_power_status(data);
                break;

        case I8K_GET_TEMP:
                val = i8k_get_temp(data, 0);
                break;

        case I8K_GET_SPEED:
                if (copy_from_user(&val, argp, sizeof(int)))
                        return -EFAULT;

                if (val > U8_MAX || val < 0)
                        return -EINVAL;

                val = i8k_get_fan_speed(data, val);
                break;

        case I8K_GET_FAN:
                if (copy_from_user(&val, argp, sizeof(int)))
                        return -EFAULT;

                if (val > U8_MAX || val < 0)
                        return -EINVAL;

                val = i8k_get_fan_status(data, val);
                break;

        case I8K_SET_FAN:
                if (restricted && !capable(CAP_SYS_ADMIN))
                        return -EPERM;

                if (copy_from_user(&val, argp, sizeof(int)))
                        return -EFAULT;

                if (val > U8_MAX || val < 0)
                        return -EINVAL;

                if (copy_from_user(&speed, argp + 1, sizeof(int)))
                        return -EFAULT;

                speed = clamp_val(speed, 0, data->i8k_fan_max);

                mutex_lock(&data->i8k_mutex);
                err = i8k_set_fan(data, val, speed);
                if (err < 0)
                        val = err;
                else
                        val = i8k_get_fan_status(data, val);
                mutex_unlock(&data->i8k_mutex);
                break;

        default:
                return -ENOIOCTLCMD;
        }

        if (val < 0)
                return val;

        if (copy_to_user(argp, &val, sizeof(int)))
                return -EFAULT;

        return 0;
}

/*
 * Print the information for /proc/i8k.
 */
static int i8k_proc_show(struct seq_file *seq, void *offset)
{
        struct dell_smm_data *data = seq->private;
        int fn_key, cpu_temp, ac_power;
        int left_fan, right_fan, left_speed, right_speed;

        cpu_temp        = i8k_get_temp(data, 0);                        /* 11100 µs */
        left_fan        = i8k_get_fan_status(data, I8K_FAN_LEFT);       /*   580 µs */
        right_fan       = i8k_get_fan_status(data, I8K_FAN_RIGHT);      /*   580 µs */
        left_speed      = i8k_get_fan_speed(data, I8K_FAN_LEFT);        /*   580 µs */
        right_speed     = i8k_get_fan_speed(data, I8K_FAN_RIGHT);       /*   580 µs */
        fn_key          = i8k_get_fn_status(data);                      /*   750 µs */
        if (power_status)
                ac_power = i8k_get_power_status(data);                  /* 14700 µs */
        else
                ac_power = -1;

        /*
         * Info:
         *
         * 1)  Format version (this will change if format changes)
         * 2)  BIOS version
         * 3)  BIOS machine ID
         * 4)  Cpu temperature
         * 5)  Left fan status
         * 6)  Right fan status
         * 7)  Left fan speed
         * 8)  Right fan speed
         * 9)  AC power
         * 10) Fn Key status
         */
        seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
                   I8K_PROC_FMT,
                   data->bios_version,
                   (restricted && !capable(CAP_SYS_ADMIN)) ? "-1" : data->bios_machineid,
                   cpu_temp,
                   left_fan, right_fan, left_speed, right_speed,
                   ac_power, fn_key);

        return 0;
}

static int i8k_open_fs(struct inode *inode, struct file *file)
{
        return single_open(file, i8k_proc_show, pde_data(inode));
}

static const struct proc_ops i8k_proc_ops = {
        .proc_open      = i8k_open_fs,
        .proc_read      = seq_read,
        .proc_lseek     = seq_lseek,
        .proc_release   = single_release,
        .proc_ioctl     = i8k_ioctl,
};

static void i8k_exit_procfs(void *param)
{
        remove_proc_entry("i8k", NULL);
}

static void __init i8k_init_procfs(struct device *dev)
{
        struct dell_smm_data *data = dev_get_drvdata(dev);

        strscpy(data->bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION),
                sizeof(data->bios_version));
        strscpy(data->bios_machineid, i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
                sizeof(data->bios_machineid));

        /* Only register exit function if creation was successful */
        if (proc_create_data("i8k", 0, NULL, &i8k_proc_ops, data))
                devm_add_action_or_reset(dev, i8k_exit_procfs, NULL);
}

#else

static void __init i8k_init_procfs(struct device *dev)
{
}

#endif

static int dell_smm_get_max_state(struct thermal_cooling_device *dev, unsigned long *state)
{
        struct dell_smm_cooling_data *cdata = dev->devdata;

        *state = cdata->data->i8k_fan_max;

        return 0;
}

static int dell_smm_get_cur_state(struct thermal_cooling_device *dev, unsigned long *state)
{
        struct dell_smm_cooling_data *cdata = dev->devdata;
        int ret;

        ret = i8k_get_fan_status(cdata->data, cdata->fan_num);
        if (ret < 0)
                return ret;

        /*
         * A fan state bigger than i8k_fan_max might indicate that
         * the fan is currently in automatic mode.
         */
        if (ret > cdata->data->i8k_fan_max)
                return -ENODATA;

        *state = ret;

        return 0;
}

static int dell_smm_set_cur_state(struct thermal_cooling_device *dev, unsigned long state)
{
        struct dell_smm_cooling_data *cdata = dev->devdata;
        struct dell_smm_data *data = cdata->data;
        int ret;

        if (state > data->i8k_fan_max)
                return -EINVAL;

        mutex_lock(&data->i8k_mutex);
        ret = i8k_set_fan(data, cdata->fan_num, (int)state);
        mutex_unlock(&data->i8k_mutex);

        return ret;
}

static const struct thermal_cooling_device_ops dell_smm_cooling_ops = {
        .get_max_state = dell_smm_get_max_state,
        .get_cur_state = dell_smm_get_cur_state,
        .set_cur_state = dell_smm_set_cur_state,
};

static umode_t dell_smm_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
                                   int channel)
{
        const struct dell_smm_data *data = drvdata;

        switch (type) {
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_input:
                        /* _i8k_get_temp() is fine since we do not care about the actual value */
                        if (data->temp_type[channel] >= 0 || _i8k_get_temp(data, channel) >= 0)
                                return 0444;

                        break;
                case hwmon_temp_label:
                        if (data->temp_type[channel] >= 0)
                                return 0444;

                        break;
                default:
                        break;
                }
                break;
        case hwmon_fan:
                if (disallow_fan_support)
                        break;

                switch (attr) {
                case hwmon_fan_input:
                        if (data->fan[channel])
                                return 0444;

                        break;
                case hwmon_fan_label:
                        if (data->fan[channel] && !disallow_fan_type_call)
                                return 0444;

                        break;
                case hwmon_fan_min:
                case hwmon_fan_max:
                case hwmon_fan_target:
                        if (data->fan_nominal_speed[channel])
                                return 0444;

                        break;
                default:
                        break;
                }
                break;
        case hwmon_pwm:
                if (disallow_fan_support)
                        break;

                switch (attr) {
                case hwmon_pwm_input:
                        if (data->fan[channel])
                                return 0644;

                        break;
                case hwmon_pwm_enable:
                        if (auto_fan) {
                                /*
                                 * The setting affects all fans, so only create a
                                 * single attribute for the first fan channel.
                                 */
                                if (channel != 0)
                                        return 0;

                                /*
                                 * There is no command for retrieve the current status
                                 * from BIOS, and userspace/firmware itself can change
                                 * it.
                                 * Thus we can only provide write-only access for now.
                                 */
                                return 0200;
                        }

                        if (data->fan[channel] && data->i8k_fan_max < I8K_FAN_AUTO)
                                return 0644;

                        break;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return 0;
}

static int dell_smm_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
                         long *val)
{
        struct dell_smm_data *data = dev_get_drvdata(dev);
        int mult = data->i8k_fan_mult;
        int ret;

        switch (type) {
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_input:
                        ret = i8k_get_temp(data, channel);
                        if (ret < 0)
                                return ret;

                        *val = ret * 1000;

                        return 0;
                default:
                        break;
                }
                break;
        case hwmon_fan:
                switch (attr) {
                case hwmon_fan_input:
                        ret = i8k_get_fan_speed(data, channel);
                        if (ret < 0)
                                return ret;

                        *val = ret;

                        return 0;
                case hwmon_fan_min:
                        *val = data->fan_nominal_speed[channel][0] * mult;

                        return 0;
                case hwmon_fan_max:
                        *val = data->fan_nominal_speed[channel][data->i8k_fan_max] * mult;

                        return 0;
                case hwmon_fan_target:
                        ret = i8k_get_fan_status(data, channel);
                        if (ret < 0)
                                return ret;

                        if (ret > data->i8k_fan_max)
                                ret = data->i8k_fan_max;

                        *val = data->fan_nominal_speed[channel][ret] * mult;

                        return 0;
                default:
                        break;
                }
                break;
        case hwmon_pwm:
                ret = i8k_get_fan_status(data, channel);
                if (ret < 0)
                        return ret;

                switch (attr) {
                case hwmon_pwm_input:
                        /*
                         * A fan state bigger than i8k_fan_max might indicate that
                         * the fan is currently in automatic mode.
                         */
                        if (ret > data->i8k_fan_max)
                                return -ENODATA;

                        *val = clamp_val(ret * data->i8k_pwm_mult, 0, 255);

                        return 0;
                case hwmon_pwm_enable:
                        if (ret == I8K_FAN_AUTO)
                                *val = 2;
                        else
                                *val = 1;

                        return 0;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return -EOPNOTSUPP;
}

static const char *dell_smm_fan_label(struct dell_smm_data *data, int channel)
{
        bool dock = false;
        int type = i8k_get_fan_type(data, channel);

        if (type < 0)
                return ERR_PTR(type);

        if (type & 0x10) {
                dock = true;
                type &= 0x0F;
        }

        if (type >= ARRAY_SIZE(fan_labels))
                type = ARRAY_SIZE(fan_labels) - 1;

        return dock ? docking_labels[type] : fan_labels[type];
}

static int dell_smm_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
                                int channel, const char **str)
{
        struct dell_smm_data *data = dev_get_drvdata(dev);

        switch (type) {
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_label:
                        *str = temp_labels[data->temp_type[channel]];
                        return 0;
                default:
                        break;
                }
                break;
        case hwmon_fan:
                switch (attr) {
                case hwmon_fan_label:
                        *str = dell_smm_fan_label(data, channel);
                        return PTR_ERR_OR_ZERO(*str);
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return -EOPNOTSUPP;
}

static int dell_smm_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
                          long val)
{
        struct dell_smm_data *data = dev_get_drvdata(dev);
        unsigned long pwm;
        bool enable;
        int err;

        switch (type) {
        case hwmon_pwm:
                switch (attr) {
                case hwmon_pwm_input:
                        pwm = clamp_val(DIV_ROUND_CLOSEST(val, data->i8k_pwm_mult), 0,
                                        data->i8k_fan_max);

                        mutex_lock(&data->i8k_mutex);
                        err = i8k_set_fan(data, channel, pwm);
                        mutex_unlock(&data->i8k_mutex);

                        if (err < 0)
                                return err;

                        return 0;
                case hwmon_pwm_enable:
                        switch (val) {
                        case 1:
                                enable = false;
                                break;
                        case 2:
                                enable = true;
                                break;
                        default:
                                return -EINVAL;
                        }

                        mutex_lock(&data->i8k_mutex);
                        if (auto_fan) {
                                err = i8k_enable_fan_auto_mode(data, enable);
                        } else {
                                /*
                                 * When putting the fan into manual control mode we have to ensure
                                 * that the device does not overheat until the userspace fan control
                                 * software takes over. Because of this we set the fan speed to
                                 * i8k_fan_max when disabling automatic fan control.
                                 */
                                if (enable)
                                        err = i8k_set_fan(data, channel, I8K_FAN_AUTO);
                                else
                                        err = i8k_set_fan(data, channel, data->i8k_fan_max);
                        }
                        mutex_unlock(&data->i8k_mutex);

                        if (err < 0)
                                return err;

                        return 0;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return -EOPNOTSUPP;
}

static const struct hwmon_ops dell_smm_ops = {
        .is_visible = dell_smm_is_visible,
        .read = dell_smm_read,
        .read_string = dell_smm_read_string,
        .write = dell_smm_write,
};

static const struct hwmon_channel_info * const dell_smm_info[] = {
        HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
        HWMON_CHANNEL_INFO(temp,
                           HWMON_T_INPUT | HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_LABEL
                           ),
        HWMON_CHANNEL_INFO(fan,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
                           HWMON_F_TARGET,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
                           HWMON_F_TARGET,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
                           HWMON_F_TARGET,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
                           HWMON_F_TARGET
                           ),
        HWMON_CHANNEL_INFO(pwm,
                           HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
                           HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
                           HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
                           HWMON_PWM_INPUT | HWMON_PWM_ENABLE
                           ),
        NULL
};

static const struct hwmon_chip_info dell_smm_chip_info = {
        .ops = &dell_smm_ops,
        .info = dell_smm_info,
};

static int dell_smm_init_cdev(struct device *dev, u8 fan_num)
{
        struct dell_smm_data *data = dev_get_drvdata(dev);
        struct thermal_cooling_device *cdev;
        struct dell_smm_cooling_data *cdata;
        int ret = 0;
        char *name;

        name = kasprintf(GFP_KERNEL, "dell-smm-fan%u", fan_num + 1);
        if (!name)
                return -ENOMEM;

        cdata = devm_kmalloc(dev, sizeof(*cdata), GFP_KERNEL);
        if (cdata) {
                cdata->fan_num = fan_num;
                cdata->data = data;
                cdev = devm_thermal_of_cooling_device_register(dev, NULL, name, cdata,
                                                               &dell_smm_cooling_ops);
                if (IS_ERR(cdev)) {
                        devm_kfree(dev, cdata);
                        ret = PTR_ERR(cdev);
                }
        } else {
                ret = -ENOMEM;
        }

        kfree(name);

        return ret;
}

static int dell_smm_init_hwmon(struct device *dev)
{
        struct dell_smm_data *data = dev_get_drvdata(dev);
        struct device *dell_smm_hwmon_dev;
        int state, err;
        u8 i;

        for (i = 0; i < DELL_SMM_NO_TEMP; i++) {
                data->temp_type[i] = i8k_get_temp_type(data, i);
                if (data->temp_type[i] < 0)
                        continue;

                if (data->temp_type[i] >= ARRAY_SIZE(temp_labels))
                        data->temp_type[i] = ARRAY_SIZE(temp_labels) - 1;
        }

        for (i = 0; i < DELL_SMM_NO_FANS; i++) {
                data->fan_type[i] = INT_MIN;
                err = i8k_get_fan_status(data, i);
                if (err < 0)
                        err = i8k_get_fan_type(data, i);

                if (err < 0)
                        continue;

                data->fan[i] = true;

                /* the cooling device is not critical, ignore failures */
                if (IS_REACHABLE(CONFIG_THERMAL)) {
                        err = dell_smm_init_cdev(dev, i);
                        if (err < 0)
                                dev_warn(dev, "Failed to register cooling device for fan %u\n",
                                         i + 1);
                }

                data->fan_nominal_speed[i] = devm_kmalloc_array(dev, data->i8k_fan_max + 1,
                                                                sizeof(*data->fan_nominal_speed[i]),
                                                                GFP_KERNEL);
                if (!data->fan_nominal_speed[i])
                        continue;

                for (state = 0; state <= data->i8k_fan_max; state++) {
                        err = i8k_get_fan_nominal_speed(data, i, state);
                        if (err < 0) {
                                /* Mark nominal speed table as invalid in case of error */
                                devm_kfree(dev, data->fan_nominal_speed[i]);
                                data->fan_nominal_speed[i] = NULL;
                                break;
                        }
                        data->fan_nominal_speed[i][state] = err;
                        /*
                         * Autodetect fan multiplier based on nominal rpm if multiplier
                         * was not specified as module param or in DMI. If fan reports
                         * rpm value too high then set multiplier to 1.
                         */
                        if (!fan_mult && err > I8K_FAN_RPM_THRESHOLD)
                                data->i8k_fan_mult = 1;
                }
        }

        dell_smm_hwmon_dev = devm_hwmon_device_register_with_info(dev, "dell_smm", data,
                                                                  &dell_smm_chip_info, NULL);

        return PTR_ERR_OR_ZERO(dell_smm_hwmon_dev);
}

static int dell_smm_init_data(struct device *dev, const struct dell_smm_ops *ops)
{
        struct dell_smm_data *data;

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

        mutex_init(&data->i8k_mutex);
        dev_set_drvdata(dev, data);

        data->ops = ops;
        /* All options must not be 0 */
        data->i8k_fan_mult = fan_mult ? : I8K_FAN_MULT;
        if (data->i8k_fan_mult > DELL_SMM_MAX_FAN_MULT) {
                dev_err(dev,
                        "fan multiplier %u is too large (max %u)\n",
                        data->i8k_fan_mult, DELL_SMM_MAX_FAN_MULT);
                return -EINVAL;
        }
        data->i8k_fan_max = fan_max ? : I8K_FAN_HIGH;
        data->i8k_pwm_mult = DIV_ROUND_UP(255, data->i8k_fan_max);

        return 0;
}

static const struct dmi_system_id i8k_dmi_table[] __initconst = {
        {
                .ident = "Dell G5 5590",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "G5 5590"),
                },
        },
        {
                .ident = "Dell G5 5505",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "G5 5505"),
                },
        },
        {
                .ident = "Dell Inspiron",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
                },
        },
        {
                .ident = "Dell Latitude",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
                },
        },
        {
                .ident = "Dell Inspiron 2",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
                },
        },
        {
                .ident = "Dell Latitude 2",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
                },
        },
        {       /* UK Inspiron 6400  */
                .ident = "Dell Inspiron 3",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
                },
        },
        {
                .ident = "Dell Inspiron 3",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
                },
        },
        {
                .ident = "Dell OptiPlex 7080",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7080"),
                },
        },
        {
                .ident = "Dell OptiPlex 7060",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7060"),
                },
        },
        {
                .ident = "Dell OptiPlex 7050",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7050"),
                },
        },
        {
                .ident = "Dell OptiPlex 7040",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7040"),
                },
        },
        {
                .ident = "Dell Precision",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
                },
        },
        {
                .ident = "Dell Vostro",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
                },
        },
        {
                .ident = "Dell Studio",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
                },
        },
        {
                .ident = "Dell XPS M140",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "MXC051"),
                },
        },
        {
                .ident = "Dell XPS",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "XPS"),
                },
        },
        { }
};

MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);

/*
 * Only use for machines which need some special configuration
 * in order to work correctly (e.g. if autoconfig fails on this machines).
 */
struct i8k_config_data {
        uint fan_mult;
        uint fan_max;
};

enum i8k_configs {
        DELL_LATITUDE_D520,
        DELL_STUDIO,
        DELL_XPS,
};

static const struct i8k_config_data i8k_config_data[] __initconst = {
        [DELL_LATITUDE_D520] = {
                .fan_mult = 1,
                .fan_max = I8K_FAN_TURBO,
        },
        [DELL_STUDIO] = {
                .fan_mult = 1,
                .fan_max = I8K_FAN_HIGH,
        },
        [DELL_XPS] = {
                .fan_mult = 1,
                .fan_max = I8K_FAN_HIGH,
        },
};

static const struct dmi_system_id i8k_config_dmi_table[] __initconst = {
        {
                .ident = "Dell Latitude D520",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Latitude D520"),
                },
                .driver_data = (void *)&i8k_config_data[DELL_LATITUDE_D520],
        },
        {
                .ident = "Dell Studio",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
                },
                .driver_data = (void *)&i8k_config_data[DELL_STUDIO],
        },
        {
                .ident = "Dell XPS M140",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "MXC051"),
                },
                .driver_data = (void *)&i8k_config_data[DELL_XPS],
        },
        { }
};

/*
 * On some machines once I8K_SMM_GET_FAN_TYPE is issued then CPU fan speed
 * randomly going up and down due to bug in Dell SMM or BIOS. Here is blacklist
 * of affected Dell machines for which we disallow I8K_SMM_GET_FAN_TYPE call.
 * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=100121
 */
static const struct dmi_system_id i8k_blacklist_fan_type_dmi_table[] __initconst = {
        {
                .ident = "Dell Studio XPS 8000",
                .matches = {
                        DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8000"),
                },
        },
        {
                .ident = "Dell Studio XPS 8100",
                .matches = {
                        DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8100"),
                },
        },
        {
                .ident = "Dell Inspiron 580",
                .matches = {
                        DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 580 "),
                },
        },
        {
                .ident = "Dell Inspiron 3505",
                .matches = {
                        DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 3505"),
                },
        },
        { }
};

/*
 * On some machines all fan related SMM functions implemented by Dell BIOS
 * firmware freeze kernel for about 500ms. Until Dell fixes these problems fan
 * support for affected blacklisted Dell machines stay disabled.
 * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=195751
 */
static const struct dmi_system_id i8k_blacklist_fan_support_dmi_table[] __initconst = {
        {
                .ident = "Dell Inspiron 7720",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 7720"),
                },
        },
        {
                .ident = "Dell Vostro 3360",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Vostro 3360"),
                },
        },
        {
                .ident = "Dell XPS13 9333",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
                },
        },
        {
                .ident = "Dell XPS 15 L502X",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L502X"),
                },
        },
        { }
};

struct i8k_fan_control_data {
        unsigned int manual_fan;
        unsigned int auto_fan;
};

enum i8k_fan_controls {
        I8K_FAN_30A3_31A3,
        I8K_FAN_34A3_35A3,
};

static const struct i8k_fan_control_data i8k_fan_control_data[] __initconst = {
        [I8K_FAN_30A3_31A3] = {
                .manual_fan = 0x30a3,
                .auto_fan = 0x31a3,
        },
        [I8K_FAN_34A3_35A3] = {
                .manual_fan = 0x34a3,
                .auto_fan = 0x35a3,
        },
};

static const struct dmi_system_id i8k_whitelist_fan_control[] __initconst = {
        {
                .ident = "Dell G5 5505",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "G5 5505"),

                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
        },
        {
                .ident = "Dell Latitude 5480",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude 5480"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
        },
        {
                .ident = "Dell Latitude 7320",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude 7320"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_30A3_31A3],
        },
        {
                .ident = "Dell Latitude E6440",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E6440"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
        },
        {
                .ident = "Dell Latitude E7440",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E7440"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
        },
        {
                .ident = "Dell Precision 5530",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 5530"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
        },
        {
                .ident = "Dell Precision 7510",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 7510"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
        },
        {
                .ident = "Dell Precision 7540",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 7540"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
        },
        {
                .ident = "Dell XPS 13 7390",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS 13 7390"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
        },
        {
                .ident = "Dell XPS 13 9370",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS 13 9370"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_30A3_31A3],
        },
        {
                .ident = "Dell Optiplex 7000",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7000"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
        },
        {
                .ident = "Dell XPS 9315",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS 9315"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_30A3_31A3],
        },
        {
                .ident = "Dell G15 5510",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Dell G15 5510"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_30A3_31A3],
        },
        {
                .ident = "Dell G15 5511",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Dell G15 5511"),
                },
                .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_30A3_31A3],
        },
        { }
};

/*
 * Legacy SMM backend driver.
 */
static int __init dell_smm_probe(struct platform_device *pdev)
{
        int ret;

        ret = dell_smm_init_data(&pdev->dev, &i8k_smm_ops);
        if (ret < 0)
                return ret;

        ret = dell_smm_init_hwmon(&pdev->dev);
        if (ret)
                return ret;

        i8k_init_procfs(&pdev->dev);

        return 0;
}

static struct platform_driver dell_smm_driver = {
        .driver         = {
                .name   = KBUILD_MODNAME,
        },
};

static struct platform_device *dell_smm_device;

/*
 * WMI SMM backend driver.
 */
static int dell_smm_wmi_probe(struct wmi_device *wdev, const void *context)
{
        struct dell_smm_ops *ops;
        int ret;

        ops = devm_kzalloc(&wdev->dev, sizeof(*ops), GFP_KERNEL);
        if (!ops)
                return -ENOMEM;

        ops->smm_call = wmi_smm_call;
        ops->smm_dev = &wdev->dev;

        if (dell_smm_get_signature(ops, I8K_SMM_GET_DELL_SIG1) &&
            dell_smm_get_signature(ops, I8K_SMM_GET_DELL_SIG2))
                return -ENODEV;

        ret = dell_smm_init_data(&wdev->dev, ops);
        if (ret < 0)
                return ret;

        return dell_smm_init_hwmon(&wdev->dev);
}

static const struct wmi_device_id dell_smm_wmi_id_table[] = {
        { DELL_SMM_WMI_GUID, NULL },
        { }
};
MODULE_DEVICE_TABLE(wmi, dell_smm_wmi_id_table);

static struct wmi_driver dell_smm_wmi_driver = {
        .driver = {
                .name = KBUILD_MODNAME,
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
        },
        .id_table = dell_smm_wmi_id_table,
        .probe = dell_smm_wmi_probe,
        .no_singleton = true,
};

/*
 * Probe for the presence of a supported laptop.
 */
static void __init dell_smm_init_dmi(void)
{
        struct i8k_fan_control_data *control;
        struct i8k_config_data *config;
        const struct dmi_system_id *id;

        if (dmi_check_system(i8k_blacklist_fan_support_dmi_table)) {
                if (!force) {
                        pr_notice("Disabling fan support due to BIOS bugs\n");
                        disallow_fan_support = true;
                } else {
                        pr_warn("Enabling fan support despite BIOS bugs\n");
                }
        }

        if (dmi_check_system(i8k_blacklist_fan_type_dmi_table)) {
                if (!force) {
                        pr_notice("Disabling fan type call due to BIOS bugs\n");
                        disallow_fan_type_call = true;
                } else {
                        pr_warn("Enabling fan type call despite BIOS bugs\n");
                }
        }

        /*
         * Set fan multiplier and maximal fan speed from DMI config.
         * Values specified in module parameters override values from DMI.
         */
        id = dmi_first_match(i8k_config_dmi_table);
        if (id && id->driver_data) {
                config = id->driver_data;
                if (!fan_mult && config->fan_mult)
                        fan_mult = config->fan_mult;

                if (!fan_max && config->fan_max)
                        fan_max = config->fan_max;
        }

        id = dmi_first_match(i8k_whitelist_fan_control);
        if (id && id->driver_data) {
                control = id->driver_data;
                manual_fan = control->manual_fan;
                auto_fan = control->auto_fan;

                pr_info("Enabling support for setting automatic/manual fan control\n");
        }
}

static int __init dell_smm_legacy_check(void)
{
        if (!dmi_check_system(i8k_dmi_table)) {
                if (!ignore_dmi && !force)
                        return -ENODEV;

                pr_info("Probing for legacy SMM handler on unsupported machine\n");
                pr_info("vendor=%s, model=%s, version=%s\n",
                        i8k_get_dmi_data(DMI_SYS_VENDOR),
                        i8k_get_dmi_data(DMI_PRODUCT_NAME),
                        i8k_get_dmi_data(DMI_BIOS_VERSION));
        }

        if (dell_smm_get_signature(&i8k_smm_ops, I8K_SMM_GET_DELL_SIG1) &&
            dell_smm_get_signature(&i8k_smm_ops, I8K_SMM_GET_DELL_SIG2)) {
                if (!force)
                        return -ENODEV;

                pr_warn("Forcing legacy SMM calls on a possibly incompatible machine\n");
        }

        return 0;
}

static int __init i8k_init(void)
{
        int ret;

        dell_smm_init_dmi();

        ret = dell_smm_legacy_check();
        if (ret < 0) {
                /*
                 * On modern machines, SMM communication happens over WMI, meaning
                 * the SMM handler might not react to legacy SMM calls.
                 */
                return wmi_driver_register(&dell_smm_wmi_driver);
        }

        dell_smm_device = platform_create_bundle(&dell_smm_driver, dell_smm_probe, NULL, 0, NULL,
                                                 0);

        return PTR_ERR_OR_ZERO(dell_smm_device);
}

static void __exit i8k_exit(void)
{
        if (dell_smm_device) {
                platform_device_unregister(dell_smm_device);
                platform_driver_unregister(&dell_smm_driver);
        } else {
                wmi_driver_unregister(&dell_smm_wmi_driver);
        }
}

module_init(i8k_init);
module_exit(i8k_exit);