Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1468 insertions, 0 deletions

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
new file mode 100644
index 000000000..1572b5416
--- /dev/null
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -0,0 +1,1468 @@
+// 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/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/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/i8k.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_NO_TEMP	10
+#define DELL_SMM_NO_FANS	3
+
+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;
+	bool disallow_fan_type_call;
+	bool disallow_fan_support;
+	unsigned int manual_fan;
+	unsigned int auto_fan;
+	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];
+};
+
+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)");
+
+struct smm_regs {
+	unsigned int eax;
+	unsigned int ebx;
+	unsigned int ecx;
+	unsigned int edx;
+	unsigned int esi;
+	unsigned int edi;
+};
+
+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)
+{
+	ktime_t calltime = ktime_get();
+	struct smm_regs *regs = par;
+	int eax = regs->eax;
+	int ebx = regs->ebx;
+	unsigned char carry;
+	long long duration;
+
+	/* 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));
+
+	duration = ktime_us_delta(ktime_get(), calltime);
+	pr_debug("smm(0x%.4x 0x%.4x) = 0x%.4x carry: %d (took %7lld usecs)\n",
+		 eax, ebx, regs->eax & 0xffff, carry, duration);
+
+	if (duration > DELL_SMM_MAX_DURATION)
+		pr_warn_once("SMM call took %lld usecs!\n", duration);
+
+	if (carry || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
+		return -EINVAL;
+
+	return 0;
+}
+
+/*
+ * Call the System Management Mode BIOS.
+ */
+static int i8k_smm(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;
+}
+
+/*
+ * 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 (data->disallow_fan_support)
+		return -EINVAL;
+
+	return i8k_smm(&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 (data->disallow_fan_support)
+		return -EINVAL;
+
+	return i8k_smm(&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 (data->disallow_fan_support || data->disallow_fan_type_call)
+		return -EINVAL;
+
+	return i8k_smm(&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 __init 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 (data->disallow_fan_support)
+		return -EINVAL;
+
+	return i8k_smm(&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 (data->disallow_fan_support)
+		return -EINVAL;
+
+	regs.eax = enable ? data->auto_fan : data->manual_fan;
+	return i8k_smm(&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 (data->disallow_fan_support)
+		return -EINVAL;
+
+	speed = (speed < 0) ? 0 : ((speed > data->i8k_fan_max) ? data->i8k_fan_max : speed);
+	regs.ebx = fan | (speed << 8);
+
+	return i8k_smm(&regs);
+}
+
+static int __init i8k_get_temp_type(u8 sensor)
+{
+	struct smm_regs regs = {
+		.eax = I8K_SMM_GET_TEMP_TYPE,
+		.ebx = sensor,
+	};
+
+	return i8k_smm(&regs) ? : regs.eax & 0xff;
+}
+
+/*
+ * Read the cpu temperature.
+ */
+static int _i8k_get_temp(u8 sensor)
+{
+	struct smm_regs regs = {
+		.eax = I8K_SMM_GET_TEMP,
+		.ebx = sensor,
+	};
+
+	return i8k_smm(&regs) ? : regs.eax & 0xff;
+}
+
+static int i8k_get_temp(u8 sensor)
+{
+	int temp = _i8k_get_temp(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(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 __init i8k_get_dell_signature(int req_fn)
+{
+	struct smm_regs regs = { .eax = req_fn, };
+	int rc;
+
+	rc = i8k_smm(&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(void)
+{
+	struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
+	int rc;
+
+	rc = i8k_smm(&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(void)
+{
+	struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
+	int rc;
+
+	rc = i8k_smm(&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();
+		break;
+
+	case I8K_POWER_STATUS:
+		val = i8k_get_power_status();
+		break;
+
+	case I8K_GET_TEMP:
+		val = i8k_get_temp(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;
+
+		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(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();				/*   750 µs */
+	if (power_status)
+		ac_power = i8k_get_power_status();			/* 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);
+
+	/* 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;
+
+	*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(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 (data->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] && !data->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 (data->disallow_fan_support)
+			break;
+
+		switch (attr) {
+		case hwmon_pwm_input:
+			if (data->fan[channel])
+				return 0644;
+
+			break;
+		case hwmon_pwm_enable:
+			if (data->auto_fan)
+				/*
+				 * 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;
+
+			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(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:
+		switch (attr) {
+		case hwmon_pwm_input:
+			ret = i8k_get_fan_status(data, channel);
+			if (ret < 0)
+				return ret;
+
+			*val = clamp_val(ret * data->i8k_pwm_mult, 0, 255);
+
+			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:
+			if (!val)
+				return -EINVAL;
+
+			if (val == 1)
+				enable = false;
+			else
+				enable = true;
+
+			mutex_lock(&data->i8k_mutex);
+			err = i8k_enable_fan_auto_mode(data, enable);
+			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 *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_CHANNEL_INFO(pwm,
+			   HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
+			   HWMON_PWM_INPUT,
+			   HWMON_PWM_INPUT
+			   ),
+	NULL
+};
+
+static const struct hwmon_chip_info dell_smm_chip_info = {
+	.ops = &dell_smm_ops,
+	.info = dell_smm_info,
+};
+
+static int __init 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 __init 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(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);
+}
+
+struct i8k_config_data {
+	uint fan_mult;
+	uint fan_max;
+};
+
+enum i8k_configs {
+	DELL_LATITUDE_D520,
+	DELL_PRECISION_490,
+	DELL_STUDIO,
+	DELL_XPS,
+};
+
+/*
+ * Only use for machines which need some special configuration
+ * in order to work correctly (e.g. if autoconfig fails on this machines).
+ */
+
+static const struct i8k_config_data i8k_config_data[] __initconst = {
+	[DELL_LATITUDE_D520] = {
+		.fan_mult = 1,
+		.fan_max = I8K_FAN_TURBO,
+	},
+	[DELL_PRECISION_490] = {
+		.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_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 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 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 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 Precision 490",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME,
+				  "Precision WorkStation 490"),
+		},
+		.driver_data = (void *)&i8k_config_data[DELL_PRECISION_490],
+	},
+	{
+		.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"),
+		},
+		.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],
+	},
+	{
+		.ident = "Dell XPS",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "XPS"),
+		},
+	},
+	{ }
+};
+
+MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
+
+/*
+ * 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_34A3_35A3,
+};
+
+static const struct i8k_fan_control_data i8k_fan_control_data[] __initconst = {
+	[I8K_FAN_34A3_35A3] = {
+		.manual_fan = 0x34a3,
+		.auto_fan = 0x35a3,
+	},
+};
+
+static const struct dmi_system_id i8k_whitelist_fan_control[] __initconst = {
+	{
+		.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 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 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],
+	},
+	{ }
+};
+
+static int __init dell_smm_probe(struct platform_device *pdev)
+{
+	struct dell_smm_data *data;
+	const struct dmi_system_id *id, *fan_control;
+	int ret;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(struct dell_smm_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	mutex_init(&data->i8k_mutex);
+	platform_set_drvdata(pdev, data);
+
+	if (dmi_check_system(i8k_blacklist_fan_support_dmi_table)) {
+		if (!force) {
+			dev_notice(&pdev->dev, "Disabling fan support due to BIOS bugs\n");
+			data->disallow_fan_support = true;
+		} else {
+			dev_warn(&pdev->dev, "Enabling fan support despite BIOS bugs\n");
+		}
+	}
+
+	if (dmi_check_system(i8k_blacklist_fan_type_dmi_table)) {
+		if (!force) {
+			dev_notice(&pdev->dev, "Disabling fan type call due to BIOS bugs\n");
+			data->disallow_fan_type_call = true;
+		} else {
+			dev_warn(&pdev->dev, "Enabling fan type call despite BIOS bugs\n");
+		}
+	}
+
+	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));
+
+	/*
+	 * Set fan multiplier and maximal fan speed from dmi config
+	 * Values specified in module parameters override values from dmi
+	 */
+	id = dmi_first_match(i8k_dmi_table);
+	if (id && id->driver_data) {
+		const struct i8k_config_data *conf = id->driver_data;
+
+		if (!fan_mult && conf->fan_mult)
+			fan_mult = conf->fan_mult;
+
+		if (!fan_max && conf->fan_max)
+			fan_max = conf->fan_max;
+	}
+
+	/* All options must not be 0 */
+	data->i8k_fan_mult = fan_mult ? : I8K_FAN_MULT;
+	data->i8k_fan_max = fan_max ? : I8K_FAN_HIGH;
+	data->i8k_pwm_mult = DIV_ROUND_UP(255, data->i8k_fan_max);
+
+	fan_control = dmi_first_match(i8k_whitelist_fan_control);
+	if (fan_control && fan_control->driver_data) {
+		const struct i8k_fan_control_data *control = fan_control->driver_data;
+
+		data->manual_fan = control->manual_fan;
+		data->auto_fan = control->auto_fan;
+		dev_info(&pdev->dev, "enabling support for setting automatic/manual fan control\n");
+	}
+
+	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;
+
+/*
+ * Probe for the presence of a supported laptop.
+ */
+static int __init i8k_init(void)
+{
+	/*
+	 * Get DMI information
+	 */
+	if (!dmi_check_system(i8k_dmi_table)) {
+		if (!ignore_dmi && !force)
+			return -ENODEV;
+
+		pr_info("not running on a supported Dell system.\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));
+	}
+
+	/*
+	 * Get SMM Dell signature
+	 */
+	if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
+	    i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
+		pr_err("unable to get SMM Dell signature\n");
+		if (!force)
+			return -ENODEV;
+	}
+
+	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)
+{
+	platform_device_unregister(dell_smm_device);
+	platform_driver_unregister(&dell_smm_driver);
+}
+
+module_init(i8k_init);
+module_exit(i8k_exit);