diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 72f4e6065bae..34e4bc086bdb 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -159,6 +159,7 @@ Hardware Monitoring Kernel Drivers
    mp2888
    mp2975
    mp5023
+   msi-psu
    nct6683
    nct6775
    nct7802
diff --git a/Documentation/hwmon/msi-psu.rst b/Documentation/hwmon/msi-psu.rst
new file mode 100644
index 000000000000..c6750713c82c
--- /dev/null
+++ b/Documentation/hwmon/msi-psu.rst
@@ -0,0 +1,64 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver msi-psu
+=========================
+
+Supported devices:
+
+* MSI MEG Ai1300P
+
+* MSI MEG Ai1000P
+
+Author: Jack Doan
+
+Description
+-----------
+
+This driver provides a sysfs interface for MSI PSUs with a HID monitoring
+interface.
+
+Measurements for the output voltage and current for each rail are provided,
+as well as total output power, temperature, and fan control.
+
+Additional properties are available in debugfs, such as an efficiency
+measurement, and switching to/from 12V mutli-rail mode
+
+Sysfs entries
+-------------
+
+======================= ========================================================
+curr1_input             Current on the 12v psu rail
+curr2_input             Current on the 5v psu rail
+curr3_input             Current on the 3.3v psu rail
+fan1_input              RPM of psu fan
+in0_input               Voltage of the psu ac input
+in1_input               Voltage of the 12v psu rail
+in2_input               Voltage of the 5v psu rail
+in3_input               Voltage of the 3.3v psu rail
+power1_input            Total power usage
+pwm1                    PWM value for fan1. Writes to this file will switch set
+                        pwm1_enable to manual control mode
+pwm1_enable             PWM mode for fan1. (2) means "auto", and uses the
+                        built-in fan curve. (1) means manual control
+temp1_input             Temperature of the psu
+======================= ========================================================
+
+Usage Notes
+-----------
+
+It is a USB HID device, so it is auto-detected, supports hot-swapping and
+several devices at once.
+
+Debugfs entries
+---------------
+
+======================= ========================================================
+multi_rail_enabled      Single or multi rail mode of the PCIe power connectors
+efficiency              An efficiency measurement, expressed as per-ten-thousand
+(ex: 8512 == 85.12%)
+product                 Product name of the psu
+revision                Revision number of the psu
+uptime      Session uptime of the psu
+uptime_total    Total uptime of the psu
+vendor      Vendor name of the psu
+======================= ========================================================
\ No newline at end of file
diff --git a/MAINTAINERS b/MAINTAINERS
index a7c4cf8201e0..246519f9079d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14632,6 +14632,13 @@ L:	platform-driver-x86@vger.kernel.org
 S:	Maintained
 F:	drivers/platform/x86/msi-laptop.c
 
+MSI PSU HARDWARE MONITOR DRIVER
+M:	Jack Doan <me@jackdoan.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	Documentation/hwmon/msi-psu.rst
+F:	drivers/hwmon/msi-psu.c
+
 MSI WMI SUPPORT
 L:	platform-driver-x86@vger.kernel.org
 S:	Orphan
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index cf27523eed5a..2870673b56a5 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1248,6 +1248,18 @@ config SENSORS_MLXREG_FAN
 	  driver as a module, choose 'M' here: the module will be called
 	  mlxreg-fan.
 
+config SENSORS_MSI_PSU
+	tristate "MSI PSU HID controller"
+	depends on HID
+	help
+	  If you say yes here you get support for MSI power supplies with an
+	  HID monitoring interface.
+
+	  Currently this driver supports the MEG Ai1300P and MEG Ai1000P PSUs.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called msi-psu.
+
 config SENSORS_TC654
 	tristate "Microchip TC654/TC655 and compatibles"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index e84bd9685b5c..c08268073ca0 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -156,6 +156,7 @@ obj-$(CONFIG_MAX31827) += max31827.o
 obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
 obj-$(CONFIG_SENSORS_MC34VR500)	+= mc34vr500.o
 obj-$(CONFIG_SENSORS_MCP3021)	+= mcp3021.o
+obj-$(CONFIG_SENSORS_MSI_PSU)	+= msi-psu.o
 obj-$(CONFIG_SENSORS_TC654)	+= tc654.o
 obj-$(CONFIG_SENSORS_TPS23861)	+= tps23861.o
 obj-$(CONFIG_SENSORS_MLXREG_FAN) += mlxreg-fan.o
diff --git a/drivers/hwmon/msi-psu.c b/drivers/hwmon/msi-psu.c
new file mode 100644
index 000000000000..13ffb8444893
--- /dev/null
+++ b/drivers/hwmon/msi-psu.c
@@ -0,0 +1,813 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for MSI power supplies with USB-HID interfaces
+ * Heavily derived from the corsair-psu and corsair-cpro drivers,
+ * but different enough to be incompatible
+ *
+ * Copyright (C) 2023 Jack Doan <me@jackdoan.com>
+ */
+
+#include <linux/completion.h>
+#include <linux/debugfs.h>
+#include <linux/errno.h>
+#include <linux/hid.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/jiffies.h>
+#include <linux/minmax.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+/*
+ * MSI protocol for PSUs
+ *
+ * message size = 64 bytes (request and response, little endian)
+ * request:
+ *	[command][register][param0][param1][paramX]...
+ * reply:
+ *	[echo of command][echo of register][data0][data1][dataX]...
+ *
+ *	- the driver uses raw events to be accessible from userspace (though this is not really
+ *	  supported, it is just there for convenience, may be removed in the future)
+ *	- a successful reply always starts with the address and command in the same order the
+ *	  request used it
+ *	- length of the reply data is specific to the command used.
+ *	- The replies to most reads are pmbus linear11 encoded
+ *	- the PSU expects a "handshake" init command before all other commands will work
+ *	- send the handshake by sending 0x51 to the address 0xfa (packet will be [0xfa 0x51])
+ *	- the driver supports debugfs for values not fitting into the hwmon class
+ */
+
+#define DRIVER_NAME "msi-psu"
+
+#define REPLY_SIZE	40 /* max length of a reply to a single command */
+#define SAMPLE_INTERVAL_MS	50
+#define CMD_BUFFER_SIZE	64
+#define CMD_TIMEOUT_MS	250
+#define SECONDS_PER_HOUR	(60 * 60)
+#define SECONDS_PER_DAY	(SECONDS_PER_HOUR * 24)
+
+#define PSU_NAK	0xFE
+#define PSU_REG_VEND_STR	0x10
+#define PSU_REG_PROD_STR	0x11
+#define PSU_REG_REVISION	0x12
+#define PSU_REG_SERIAL	0x13 /* accepted, but returns all zeros */
+
+#define PSU_REG_IN_VOLTS	0x20
+#define PSU_REG_VOUT_12V_EACH_RAIL	0x22
+#define PSU_REG_IOUT_12V_EACH_RAIL	0x23
+#define PSU_REG_VOUT_12V	0x24
+#define PSU_REG_IOUT_12V	0x25
+#define PSU_REG_VOUT_5V	0x26
+#define PSU_REG_IOUT_5V	0x27
+#define PSU_REG_VOUT_3V	0x28
+#define PSU_REG_IOUT_3V	0x29
+#define PSU_REG_TOTAL_WATTS	0x2A
+#define PSU_REG_EFFICIENCY	0x2B
+#define PSU_REG_TEMP0	0x30
+#define PSU_REG_FAN_RPM	0x40
+#define PSU_REG_FAN_MODE	0x41
+#define PSU_REG_FAN_DUTY_CYCLE	0x42
+
+#define PSU_REG_MULTIRAIL	0xC0
+#define PSU_REG_UNKNOWN_C4	0xC4
+#define PSU_REG_UNKNOWN_C6	0xC6
+
+#define PSU_REG_UPTIME	0xD0
+#define PSU_REG_TOTAL_UPTIME	0xD1
+
+#define PSU_REG_READ_EVERYTHING	0xE0
+#define PSU_REG_SAVE_SETTINGS	0xF1
+
+#define PSU_INIT	0xFA
+#define PSU_READ	0x51
+#define PSU_WRITE	0x50
+
+#define PSU_MULTI_RAIL_ENABLED	2
+#define PSU_MULTI_RAIL_DISABLED	1
+
+#define COMBINED_12V	5
+
+#define FAN_MODE_MANUAL	3
+#define FAN_MODE_AUTO	1
+#define FAN_SPEED_MAX	100
+#define FAN_SPEED_MIN	0
+
+struct volt_amp_pair {
+	u16 volts;
+	u16 amps;
+} __packed;
+
+struct msipsu_all {
+	struct volt_amp_pair v12[6];
+	struct volt_amp_pair v5;
+	struct volt_amp_pair v3;
+	u16 watts;
+	u16 eff;
+	u16 temp;
+	u16 fan_speed;
+} __packed;
+
+struct msipsu_data {
+	struct hid_device *hdev;
+	struct device *hwmon_dev;
+	struct dentry *debugfs;
+	struct completion wait_completion;
+	struct mutex lock; /* for locking access to cmd_buffer */
+	u8 *cmd_buffer;
+	char vendor[REPLY_SIZE];
+	char product[REPLY_SIZE];
+	struct debugfs_blob_wrapper vendor_blob;
+	struct debugfs_blob_wrapper product_blob;
+	struct msipsu_all data;
+	ktime_t last_read_all;
+};
+
+/* some values are SMBus LINEAR11 data which need a conversion */
+static int msipsu_lin11_to_int(u16 v16, int scale, bool is_signed)
+{
+	s32 exponent;
+	s32 mantissa;
+	int val;
+
+	exponent = ((s16)v16) >> 11;
+	if (is_signed)
+		mantissa = ((s16)((v16 & 0x7ff) << 5)) >> 5;
+	else
+		mantissa = (u16)(v16 & 0x7ff); /* deliberately not sign-extending here */
+	val = mantissa * scale;
+
+	if (exponent >= 0)
+		val <<= exponent;
+	else
+		val >>= -exponent;
+
+	return val;
+}
+
+static int msipsu_percent_to_pwm(u16 val)
+{
+	return DIV_ROUND_CLOSEST(val * 255, 100);
+}
+
+static int msipsu_pwm_to_percent(long val)
+{
+	if (val < 0 || val > 255)
+		return -EINVAL;
+
+	return DIV_ROUND_CLOSEST(val * 100, 255);
+}
+
+static int msipsu_usb_cmd(struct msipsu_data *priv, const u8 *in, size_t in_len, void *data)
+{
+	unsigned long time;
+	int ret;
+
+	if (in_len > CMD_BUFFER_SIZE)
+		return -ENOBUFS;
+
+	memset(priv->cmd_buffer, 0, CMD_BUFFER_SIZE);
+	memcpy(priv->cmd_buffer, in, in_len);
+
+	reinit_completion(&priv->wait_completion);
+
+	ret = hid_hw_output_report(priv->hdev, priv->cmd_buffer, CMD_BUFFER_SIZE);
+	if (ret < 0)
+		return ret;
+
+	time = wait_for_completion_timeout(&priv->wait_completion,
+					   msecs_to_jiffies(CMD_TIMEOUT_MS));
+	if (!time)
+		return -ETIMEDOUT;
+
+	/*
+	 * at the start of the reply is an echo of the send command/address in the same order it
+	 * was sent. In the event a command/address is not supported, the PSU will reply with a NAK.
+	 * For an invalid read, it will look like this:
+	 *   Out -> [PSU_READ(0x51) A_FAKE_REGISTER(0x69)]
+	 *   In  <- [PSU_READ(0x51) PSU_NAK(0xFE)]
+	 * Writes differ slightly, this is the sequence for a write to a non-existent register:
+	 *   Out -> [PSU_WRITE(0x50) A_FAKE_REGISTER(0x69)]
+	 *   In  <- [PSU_WRITE(0x50) PSU_NAK(0xFE)]
+	 * And this is a rejected write (of the correct length) to a real register:
+	 *   Out -> [PSU_WRITE(0x50) PSU_REG_FAN_MODE(0x41) DATA(0x55 0x55 0x55)]
+	 *   In  <- [PSU_WRITE(0x50) PSU_REG_FAN_MODE(0x41) PSU_NAK(0xFE)]
+	 */
+	if (in[0] != priv->cmd_buffer[0] || in[1] != priv->cmd_buffer[1])
+		return -EOPNOTSUPP;
+	else if (in_len >= 3 && in[2] != PSU_NAK && priv->cmd_buffer[2] == PSU_NAK)
+		return -EINVAL;
+
+	if (data)
+		memcpy(data, priv->cmd_buffer + 2, REPLY_SIZE);
+
+	return 0;
+}
+
+static int msipsu_usb_cmd_locked(struct msipsu_data *priv, const u8 *in, size_t in_len, void *data)
+{
+	int ret;
+
+	mutex_lock(&priv->lock);
+	ret = msipsu_usb_cmd(priv, in, in_len, data);
+	mutex_unlock(&priv->lock);
+	return ret;
+}
+
+static int msipsu_fw_init(struct msipsu_data *priv)
+{
+	/*
+	 * Vendor SW always begins with a message of [0xfa, 0x51]
+	 * This init message is replied to with the model name of the PSU.
+	 */
+	const u8 init[] = {PSU_INIT, 0x51};
+	const u8 read_vendor[] = {PSU_READ, PSU_REG_VEND_STR};
+	int ret;
+
+	ret = msipsu_usb_cmd(priv, init, sizeof(init), priv->product);
+	if (ret < 0)
+		return ret;
+	ret = msipsu_usb_cmd(priv, read_vendor, sizeof(read_vendor), priv->vendor);
+	if (ret < 0)
+		return ret;
+	priv->vendor_blob.data = priv->vendor;
+	priv->product_blob.data = priv->product;
+	priv->vendor_blob.size = strnlen(priv->vendor, sizeof(priv->vendor));
+	priv->product_blob.size = strnlen(priv->product, sizeof(priv->product));
+	return ret;
+}
+
+static int msipsu_save_settings(struct msipsu_data *priv)
+{
+	const u8 cmd[] = {PSU_WRITE, PSU_REG_SAVE_SETTINGS, 0x0};
+
+	return msipsu_usb_cmd_locked(priv, cmd, sizeof(cmd), NULL);
+}
+
+static int msipsu_write_fan_settings(struct msipsu_data *priv, u8 mode, long pwm_duty)
+{
+	int ret;
+	int percent_duty = 0;
+
+	if (mode == FAN_MODE_AUTO) {
+		/* vendor SW masks off the duty cycle for auto-mode, we should do the same */
+		percent_duty = FAN_SPEED_MIN;
+	} else if (pwm_duty != 0) {
+		/*
+		 * it is an error to write duty to non-zero while the device is not in
+		 * manual-fan-mode, so switch mode automatically
+		 */
+		mode = FAN_MODE_MANUAL;
+		percent_duty = msipsu_pwm_to_percent(pwm_duty);
+		if (percent_duty < 0) /* return -EINVAL if we got a value we couldn't convert */
+			return percent_duty;
+	}
+	const u8 cmd[] = {PSU_WRITE, PSU_REG_FAN_MODE, mode, 0, percent_duty};
+
+	ret = msipsu_usb_cmd_locked(priv, cmd, sizeof(cmd), NULL);
+	if (ret < 0)
+		return ret;
+	return msipsu_save_settings(priv);
+}
+
+static int msipsu_get_all_values(struct msipsu_data *priv)
+{
+	const u8 read_cmd[] = {PSU_READ, PSU_REG_READ_EVERYTHING};
+	ktime_t t = ktime_get();
+	s64 delta = ktime_ms_delta(t, priv->last_read_all);
+
+	if (delta < SAMPLE_INTERVAL_MS)
+		return 0;
+
+	priv->last_read_all = t;
+	return msipsu_usb_cmd_locked(priv, read_cmd, sizeof(read_cmd), &priv->data);
+}
+
+static int msipsu_get_value(struct msipsu_data *priv, u8 cmd, long *val)
+{
+	u8 data[REPLY_SIZE];
+	const u8 read_cmd[] = {PSU_READ, cmd};
+	int ret = msipsu_usb_cmd_locked(priv, read_cmd, sizeof(read_cmd), data);
+
+	if (ret < 0)
+		return ret;
+
+	u16 tmp16 = (data[1] << 8) + data[0];
+
+	switch (cmd) {
+	case PSU_REG_IN_VOLTS:
+	case PSU_REG_VOUT_12V:
+	case PSU_REG_IOUT_12V:
+	case PSU_REG_VOUT_5V:
+	case PSU_REG_IOUT_5V:
+	case PSU_REG_VOUT_3V:
+	case PSU_REG_IOUT_3V:
+	case PSU_REG_TEMP0:
+		*val = msipsu_lin11_to_int(tmp16, 1000, true);
+		break;
+	case PSU_REG_EFFICIENCY:
+		*val = msipsu_lin11_to_int(tmp16, 100, true);
+		break;
+	case PSU_REG_FAN_RPM:
+		*val = msipsu_lin11_to_int(tmp16, 1, false);
+		break;
+	case PSU_REG_TOTAL_WATTS:
+		*val = msipsu_lin11_to_int(tmp16, 1000000, true);
+		break;
+	case PSU_REG_FAN_MODE:
+	    switch (data[0]) {
+		case FAN_MODE_AUTO:
+		    *val = 2;
+		    break;
+		case FAN_MODE_MANUAL:
+		    *val = 1;
+		    break;
+		default:
+		    *val = 0xff;
+		    break;
+	    }
+	    break;
+	case PSU_REG_FAN_DUTY_CYCLE:
+	case PSU_REG_TOTAL_UPTIME:
+	case PSU_REG_UPTIME:
+	case PSU_REG_REVISION:
+		*val = ((long)data[3] << 24) + (data[2] << 16) + tmp16;
+		break;
+	case PSU_REG_MULTIRAIL:
+		switch (data[0]) {
+		case PSU_MULTI_RAIL_DISABLED:
+			*val = 0;
+			break;
+		case PSU_MULTI_RAIL_ENABLED:
+			*val = 1;
+			break;
+		default:
+			*val = 0xff;
+			break;
+		}
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+	return ret;
+}
+
+static umode_t msipsu_hwmon_ops_is_visible(const void *data, enum hwmon_sensor_types type,
+					   u32 attr, int channel)
+{
+	if (type == hwmon_temp && (attr == hwmon_temp_input || attr == hwmon_temp_label))
+		return 0444;
+	else if (type == hwmon_fan && (attr == hwmon_fan_input || attr == hwmon_fan_label))
+		return 0444;
+	else if (type == hwmon_pwm && (attr == hwmon_pwm_enable || attr == hwmon_pwm_input))
+		return 0644;
+	else if (type == hwmon_power && (attr == hwmon_power_input || attr == hwmon_power_label))
+		return 0444;
+	else if (type == hwmon_in && (attr == hwmon_in_input || attr == hwmon_in_label))
+		return 0444;
+	else if (type == hwmon_curr && (attr == hwmon_curr_input || attr == hwmon_curr_label))
+		return 0444;
+
+	return 0;
+}
+
+static int msipsu_hwmon_ops_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+				 int channel, long *val)
+{
+	struct msipsu_data *priv = dev_get_drvdata(dev);
+	int ret;
+
+	if (type != hwmon_pwm) {
+		/* PWM controls don't use the "all" packet, so don't read it */
+		ret = msipsu_get_all_values(priv);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (type == hwmon_temp && attr == hwmon_temp_input) {
+		*val = msipsu_lin11_to_int(priv->data.temp, 1000, true);
+	} else if (type == hwmon_fan && attr == hwmon_fan_input) {
+		*val = msipsu_lin11_to_int(priv->data.fan_speed, 1, false);
+	} else if (type == hwmon_pwm) {
+		switch (attr) {
+		case hwmon_pwm_enable:
+			ret = msipsu_get_value(priv, PSU_REG_FAN_MODE, val);
+			*val &= 0xff;
+			break;
+		case hwmon_pwm_input:
+			ret = msipsu_get_value(priv, PSU_REG_FAN_DUTY_CYCLE, val);
+			*val &= 0xff; /* there's a "calculated" DC in the next byte up */
+			*val = msipsu_percent_to_pwm(*val);
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+	} else if (type == hwmon_power && attr == hwmon_power_input) {
+		*val = msipsu_lin11_to_int(priv->data.watts, 1000000, true);
+	} else if (type == hwmon_in && attr == hwmon_in_input) {
+		switch (channel) {
+		case 0:
+			ret = msipsu_get_value(priv, PSU_REG_IN_VOLTS, val);
+			break;
+		case 1:
+			*val = msipsu_lin11_to_int(priv->data.v12[COMBINED_12V].volts, 1000, true);
+			break;
+		case 2:
+			*val = msipsu_lin11_to_int(priv->data.v5.volts, 1000, true);
+			break;
+		case 3:
+			*val = msipsu_lin11_to_int(priv->data.v3.volts, 1000, true);
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+	} else if (type == hwmon_curr && attr == hwmon_curr_input) {
+		switch (channel) {
+		case 0:
+			*val = msipsu_lin11_to_int(priv->data.v12[COMBINED_12V].amps, 1000, true);
+			break;
+		case 1:
+			*val = msipsu_lin11_to_int(priv->data.v5.amps, 1000, true);
+			break;
+		case 2:
+			*val = msipsu_lin11_to_int(priv->data.v3.amps, 1000, true);
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+	} else {
+		return -EOPNOTSUPP;
+	}
+
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int msipsu_hwmon_ops_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+					int channel, const char **str)
+{
+	static const char *const label_volts[] = {
+		"v_in",
+		"v_out +12v",
+		"v_out +5v",
+		"v_out +3.3v"
+	};
+
+	static const char *const label_amps[] = {
+		"curr +12v",
+		"curr +5v",
+		"curr +3.3v"
+	};
+
+	if (type == hwmon_temp && attr == hwmon_temp_label) {
+		*str = "psu temp";
+		return 0;
+	} else if (type == hwmon_fan && attr == hwmon_fan_label) {
+		*str = "psu fan";
+		return 0;
+	} else if (type == hwmon_power && attr == hwmon_power_label) {
+		*str = "power total";
+		return 0;
+	} else if (type == hwmon_in && attr == hwmon_in_label && channel < 4) {
+		*str = label_volts[channel];
+		return 0;
+	} else if (type == hwmon_curr && attr == hwmon_curr_label && channel < 3) {
+		*str = label_amps[channel];
+		return 0;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static int msipsu_hwmon_ops_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+				  int channel, long val)
+{
+	struct msipsu_data *priv = dev_get_drvdata(dev);
+
+	if (type != hwmon_pwm)
+		return -EOPNOTSUPP;
+
+	switch (attr) {
+	case hwmon_pwm_enable:
+		switch (val) {
+		case 1: /* manual mode */
+			return msipsu_write_fan_settings(priv, FAN_MODE_MANUAL, FAN_SPEED_MAX);
+		case 2: /* auto mode */
+			return msipsu_write_fan_settings(priv, FAN_MODE_AUTO, FAN_SPEED_MIN);
+		default:
+			return -EINVAL;
+		}
+	case hwmon_pwm_input:
+		return msipsu_write_fan_settings(priv, FAN_MODE_MANUAL, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static const struct hwmon_ops msipsu_hwmon_ops = {
+	.is_visible = msipsu_hwmon_ops_is_visible,
+	.read = msipsu_hwmon_ops_read,
+	.write = msipsu_hwmon_ops_write,
+	.read_string = msipsu_hwmon_ops_read_string,
+};
+
+static const struct hwmon_channel_info *msipsu_info[] = {
+	HWMON_CHANNEL_INFO(chip,
+			   HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_LABEL),
+	HWMON_CHANNEL_INFO(pwm,
+			   HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
+	HWMON_CHANNEL_INFO(power,
+			   HWMON_P_INPUT | HWMON_P_LABEL),
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL),
+	HWMON_CHANNEL_INFO(curr,
+			   HWMON_C_INPUT | HWMON_C_LABEL,
+			   HWMON_C_INPUT | HWMON_C_LABEL,
+			   HWMON_C_INPUT | HWMON_C_LABEL),
+	NULL
+};
+
+static const struct hwmon_chip_info msipsu_chip_info = {
+	.ops	= &msipsu_hwmon_ops,
+	.info	= msipsu_info,
+};
+
+#ifdef CONFIG_DEBUG_FS
+
+static void print_uptime(struct seq_file *seqf, u8 cmd)
+{
+	struct msipsu_data *priv = seqf->private;
+	long val = 0;
+	int ret = msipsu_get_value(priv, cmd, &val);
+
+	if (ret < 0) {
+		seq_puts(seqf, "N/A\n");
+		return;
+	}
+
+	if (val > SECONDS_PER_DAY) {
+		seq_printf(seqf, "%ld day(s), %02ld:%02ld:%02ld\n", val / SECONDS_PER_DAY,
+			   val % SECONDS_PER_DAY / SECONDS_PER_HOUR, val % SECONDS_PER_HOUR / 60,
+			   val % 60);
+		return;
+	}
+
+	seq_printf(seqf, "%02ld:%02ld:%02ld\n", val % SECONDS_PER_DAY / SECONDS_PER_HOUR,
+		   val % SECONDS_PER_HOUR / 60, val % 60);
+}
+
+static int uptime_show(struct seq_file *seqf, void *unused)
+{
+	print_uptime(seqf, PSU_REG_UPTIME);
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(uptime);
+
+static int uptime_total_show(struct seq_file *seqf, void *unused)
+{
+	print_uptime(seqf, PSU_REG_TOTAL_UPTIME);
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(uptime_total);
+
+static int revision_show(struct seq_file *seqf, void *unused)
+{
+	struct msipsu_data *priv = seqf->private;
+	long val = 0;
+	int ret = msipsu_get_value(priv, PSU_REG_REVISION, &val);
+
+	if (ret < 0) {
+		seq_puts(seqf, "N/A\n");
+		return 0;
+	}
+
+	seq_printf(seqf, "%c.%c\n", (char)(val & 0xff), (char)((val >> 8) & 0xff));
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(revision);
+
+static int efficiency_show(struct seq_file *seqf, void *unused)
+{
+	struct msipsu_data *priv = seqf->private;
+	int ret = msipsu_get_all_values(priv);
+
+	if (ret < 0) {
+		seq_puts(seqf, "N/A\n");
+		return 0;
+	}
+
+	seq_printf(seqf, "%d\n", msipsu_lin11_to_int(priv->data.eff, 100, true));
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(efficiency);
+
+static int multi_rail_read(void *data, u64 *val)
+{
+	return msipsu_get_value((struct msipsu_data *)data, PSU_REG_MULTIRAIL, (long *)val);
+}
+
+static int msipsu_write_rail_setting(struct msipsu_data *priv, bool multi_enabled)
+{
+	long currently_enabled;
+	int ret = msipsu_get_value(priv, PSU_REG_MULTIRAIL, &currently_enabled);
+
+	if (ret < 0)
+		return ret;
+
+	/* hardware returns an error if we try to set the mode to the current mode. Avoid this. */
+	if (currently_enabled == multi_enabled)
+		return 0;
+
+	u8 to_write = multi_enabled ? PSU_MULTI_RAIL_ENABLED : PSU_MULTI_RAIL_DISABLED;
+	const u8 cmd[] = {PSU_WRITE, PSU_REG_MULTIRAIL, to_write};
+
+	ret = msipsu_usb_cmd_locked(priv, cmd, sizeof(cmd), NULL);
+	if (ret < 0)
+		return ret;
+	return msipsu_save_settings(priv);
+}
+
+static int multi_rail_write(void *data, u64 val)
+{
+	struct msipsu_data *priv = data;
+
+	switch (val) {
+	case 0:
+		return msipsu_write_rail_setting(priv, false);
+	case 1:
+		return msipsu_write_rail_setting(priv, true);
+	default:
+		return -EINVAL;
+	}
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(multi_rail_fops, multi_rail_read, multi_rail_write, "%llu\n");
+
+static void msipsu_debugfs_init(struct msipsu_data *priv)
+{
+	char name[32];
+
+	scnprintf(name, sizeof(name), "%s-%s", DRIVER_NAME, dev_name(&priv->hdev->dev));
+
+	priv->debugfs = debugfs_create_dir(name, NULL);
+	debugfs_create_file("uptime", 0444, priv->debugfs, priv, &uptime_fops);
+	debugfs_create_file("uptime_total", 0444, priv->debugfs, priv, &uptime_total_fops);
+	debugfs_create_blob("vendor", 0444, priv->debugfs, &priv->vendor_blob);
+	debugfs_create_blob("product", 0444, priv->debugfs, &priv->product_blob);
+	debugfs_create_file("revision", 0444, priv->debugfs, priv, &revision_fops);
+	debugfs_create_file("efficiency", 0444, priv->debugfs, priv, &efficiency_fops);
+	debugfs_create_file("multi_rail_enabled", 0644, priv->debugfs, priv, &multi_rail_fops);
+}
+
+#else
+
+static void msipsu_debugfs_init(struct msipsu_data *priv)
+{
+}
+
+#endif
+
+static int msipsu_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct msipsu_data *priv;
+	int ret;
+
+	priv = devm_kzalloc(&hdev->dev, sizeof(struct msipsu_data), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->cmd_buffer = devm_kmalloc(&hdev->dev, CMD_BUFFER_SIZE, GFP_KERNEL);
+	if (!priv->cmd_buffer)
+		return -ENOMEM;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	if (ret)
+		return ret;
+
+	ret = hid_hw_open(hdev);
+	if (ret)
+		goto fail_and_stop;
+
+	priv->hdev = hdev;
+	hid_set_drvdata(hdev, priv);
+	mutex_init(&priv->lock);
+	init_completion(&priv->wait_completion);
+
+	hid_device_io_start(hdev);
+
+	ret = msipsu_fw_init(priv);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "unable to initialize device (%d)\n", ret);
+		goto fail_and_close;
+	}
+
+	priv->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "msipsu", priv,
+							  &msipsu_chip_info, NULL);
+
+	if (IS_ERR(priv->hwmon_dev)) {
+		ret = PTR_ERR(priv->hwmon_dev);
+		goto fail_and_close;
+	}
+
+	msipsu_debugfs_init(priv);
+
+	return 0;
+
+fail_and_close:
+	hid_hw_close(hdev);
+fail_and_stop:
+	hid_hw_stop(hdev);
+	return ret;
+}
+
+static void msipsu_remove(struct hid_device *hdev)
+{
+	struct msipsu_data *priv = hid_get_drvdata(hdev);
+
+	debugfs_remove_recursive(priv->debugfs);
+	hwmon_device_unregister(priv->hwmon_dev);
+	hid_hw_close(hdev);
+	hid_hw_stop(hdev);
+}
+
+static int msipsu_raw_event(struct hid_device *hdev, struct hid_report *report, u8 *data, int size)
+{
+	struct msipsu_data *priv = hid_get_drvdata(hdev);
+
+	if (completion_done(&priv->wait_completion))
+		return 0;
+
+	memcpy(priv->cmd_buffer, data, min(CMD_BUFFER_SIZE, size));
+	complete(&priv->wait_completion);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int msipsu_resume(struct hid_device *hdev)
+{
+	struct msipsu_data *priv = hid_get_drvdata(hdev);
+
+	/* some PSUs turn off the microcontroller during standby, so a reinit is required */
+	return msipsu_fw_init(priv);
+}
+#endif
+
+static const struct hid_device_id msipsu_idtable[] = {
+	{ HID_USB_DEVICE(0xdb0, 0x56d4) }, /* MEG Ai1300P */
+	{ HID_USB_DEVICE(0xdb0, 0xe749) }, /* MEG Ai1000P */
+	{ },
+};
+MODULE_DEVICE_TABLE(hid, msipsu_idtable);
+
+static struct hid_driver msipsu_driver = {
+	.name		= DRIVER_NAME,
+	.id_table	= msipsu_idtable,
+	.probe		= msipsu_probe,
+	.remove		= msipsu_remove,
+	.raw_event	= msipsu_raw_event,
+#ifdef CONFIG_PM
+	.resume		= msipsu_resume,
+	.reset_resume	= msipsu_resume,
+#endif
+};
+
+static int __init msipsu_init(void)
+{
+	return hid_register_driver(&msipsu_driver);
+}
+
+static void __exit msipsu_exit(void)
+{
+	hid_unregister_driver(&msipsu_driver);
+}
+
+/*
+ * With module_init() the driver would load before the HID bus when
+ * built-in, so use late_initcall() instead.
+ */
+late_initcall(msipsu_init);
+module_exit(msipsu_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jack Doan <me@jackdoan.com>");
+MODULE_DESCRIPTION("Driver for MSI power supplies with HID sensor interface");
