@@ -613,6 +613,7 @@ ADVANTECH EIO DRIVER
 M:	Ramiro Oliveira <ramiro.oliveira@advantech.com>
 S:	Maintained
 F:	drivers/gpio/gpio-eio.c
+F:	drivers/hwmon/eio-hwmon.c
 F:	drivers/mfd/eio_core.c
 F:	include/linux/mfd/eio.h
 

@@ -2094,6 +2094,16 @@ config SENSORS_EIC7700_PVT
 	  This driver can also be built as a module. If so, the module will be
 	  called eic7700-pvt.
 
+config SENSORS_EIO
+	tristate "Advantech EIO HWMON"
+	depends on MFD_EIO
+	help
+	  If you say yes here you get support for the Advantech EIO
+	  temperature, voltage and fan speed monitoring block.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called eio-hwmon
+
 config SENSORS_EMC1403
 	tristate "SMSC EMC1403/23 thermal sensor"
 	depends on I2C

@@ -73,6 +73,7 @@ obj-$(CONFIG_SENSORS_DRIVETEMP)	+= drivetemp.o
 obj-$(CONFIG_SENSORS_DS620)	+= ds620.o
 obj-$(CONFIG_SENSORS_DS1621)	+= ds1621.o
 obj-$(CONFIG_SENSORS_EIC7700_PVT) += eic7700-pvt.o
+obj-$(CONFIG_SENSORS_EIO)	+= eio-hwmon.o
 obj-$(CONFIG_SENSORS_EMC1403)	+= emc1403.o
 obj-$(CONFIG_SENSORS_EMC1812)	+= emc1812.o
 obj-$(CONFIG_SENSORS_EMC2103)	+= emc2103.o

@@ -0,0 +1,461 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Hardware Monitoring driver for Advantech EIO embedded controller.
+ *
+ * Copyright (C) 2025 Advantech Corporation. All rights reserved.
+ */
+
+#include <linux/errno.h>
+#include <linux/hwmon.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/eio.h>
+#include <linux/module.h>
+
+#define MAX_CMD_SIZE 4
+#define MAX_NAME 32
+
+#define EIO_ITEM_INPUT		1
+#define EIO_ITEM_MAX		2
+#define EIO_ITEM_MIN		3
+#define EIO_ITEM_CRIT		4
+#define EIO_ITEM_EMERGENCY	5
+
+#define EIO_MAX_IN   8
+#define EIO_MAX_CURR 2
+#define EIO_MAX_TEMP 4
+#define EIO_MAX_FAN  4
+#define EIO_MAX_INTRUSION  1
+
+enum _sen_type {
+	NONE,
+	VOLTAGE,
+	CURRENT,
+	TEMP,
+	FAN,
+	CASEOPEN,
+};
+
+struct eio_chan {
+	bool available;
+	u8   label_idx;
+};
+
+struct eio_hwmon_dev {
+	struct device *mfd;
+	struct eio_chan in[EIO_MAX_IN];
+	struct eio_chan curr[EIO_MAX_CURR];
+	struct eio_chan temp[EIO_MAX_TEMP];
+	struct eio_chan fan[EIO_MAX_FAN];
+	struct eio_chan intrusion;
+};
+
+static struct {
+	u8 cmd;
+	u8 max;
+	signed int shift;
+	char name[MAX_NAME];
+	u8 ctrl[16];
+	u16 multi[16];
+	char item[16][MAX_NAME];
+	char labels[32][MAX_NAME];
+} sen_info[] = {
+	{ 0x00, 0, 0, "none" },
+	{ 0x12, 8, 0, "in",
+		{ 0xFF, 0x10, 0x11, 0x12 },
+		{ 1,    10,   10,   10 },
+		{ "label", "input", "max", "min" },
+		{ "5V", "5Vs5", "12V", "12Vs5",
+		  "3V3", "3V3", "5Vsb", "3Vsb",
+		  "Vcmos", "Vbat", "Vdc", "Vstb",
+		  "Vcore_a", "Vcore_b", "", "",
+		  "Voem0", "Voem1", "Voem2", "Voem3"
+		},
+	},
+	{ 0x1a, 2, 0, "curr",
+		{ 0xFF, 0x10, 0x11, 0x12 },
+		{ 1,    10,   10,   10 },
+		{ "label", "input", "max", "min" },
+		{ "dc", "oem0" },
+	},
+	{ 0x10, 4, -2731, "temp",
+		{ 0xFF, 0x10, 0x11, 0x12, 0x21, 0x41 },
+		{ 1,    100,  100,  100,  100,  100 },
+		{ "label", "input", "max", "min", "crit", "emergency" },
+		{ "cpu0", "cpu1", "cpu2", "cpu3",
+		  "sys0", "sys1", "sys2", "sys3",
+		  "aux0", "aux1", "aux2", "aux3",
+		  "dimm0", "dimm1", "dimm2", "dimm3",
+		  "pch", "gpu", "", "",
+		  "", "", "", "",
+		  "", "", "", "",
+		  "oem0", "oem1", "oem", "oem3" },
+	},
+	{ 0x24, 4, 0, "fan",
+		{ 0xFF, 0x1A },
+		{ 1, 1 },
+		{ "label", "input"},
+		{ "cpu0", "cpu1", "cpu2", "cpu3",
+		  "sys0", "sys1", "sys2", "sys3",
+		  "", "", "", "", "", "", "", "",
+		  "", "", "", "", "", "", "", "",
+		  "", "", "", "",
+		  "oem0", "oem1", "oem2", "oem3",
+		},
+	},
+	{ 0x28, 1, 0, "intrusion",
+		{ 0xFF, 0x02 },
+		{ 1, 1 },
+		{ "label", "input" },
+		{ "case_open" }
+	}
+};
+
+static struct {
+	enum _sen_type type;
+	u8   ctrl;
+	int  size;
+	bool write;
+} ctrl_para[] = {
+	{ NONE,     0x00, 0, false },
+
+	{ VOLTAGE,  0x00, 1, false }, { VOLTAGE,  0x01, 1, false },
+	{ VOLTAGE,  0x10, 2, false }, { VOLTAGE,  0x11, 2, false },
+	{ VOLTAGE,  0x12, 2, false },
+
+	{ CURRENT,  0x00, 1, false }, { CURRENT,  0x01, 1, false },
+	{ CURRENT,  0x10, 2, false }, { CURRENT,  0x11, 2, false },
+	{ CURRENT,  0x12, 2, false },
+
+	{ TEMP,	    0x00, 2, false }, { TEMP,	  0x01, 1, false },
+	{ TEMP,     0x04, 1, false }, { TEMP,	  0x10, 2, false },
+	{ TEMP,     0x11, 2, false }, { TEMP,	  0x12, 2, false },
+	{ TEMP,     0x21, 2, false }, { TEMP,	  0x41, 2, false },
+
+	{ FAN,      0x00, 1, false }, { FAN,	  0x01, 1, false },
+	{ FAN,      0x03, 1, true  }, { FAN,	  0x1A, 2, false },
+
+	{ CASEOPEN, 0x00, 1, false }, { CASEOPEN, 0x02, 1, true  },
+};
+
+static int para_idx(enum _sen_type type, u8 ctrl)
+{
+	int i;
+
+	for (i = 1 ; i < ARRAY_SIZE(ctrl_para) ; i++)
+		if (type == ctrl_para[i].type &&
+		    ctrl == ctrl_para[i].ctrl)
+			return i;
+
+	return 0;
+}
+
+static int pmc_read(struct device *mfd, enum _sen_type type, u8 dev_id, u8 ctrl, void *data)
+{
+	int idx = para_idx(type, ctrl);
+	int ret = 0;
+
+	if (idx == 0)
+		return -EINVAL;
+
+	if (WARN_ON(!data))
+		return -EINVAL;
+
+	struct pmc_op op = {
+		 .cmd       = sen_info[type].cmd | EIO_FLAG_PMC_READ,
+		 .control   = ctrl,
+		 .device_id = dev_id,
+		 .size	    = ctrl_para[idx].size,
+		 .payload   = (u8 *)data,
+	};
+
+	ret = eio_core_pmc_operation(mfd, &op);
+	return ret;
+}
+
+
+static umode_t eio_is_visible(const void *drvdata, enum hwmon_sensor_types type,
+			      u32 attr, int channel)
+{
+	const struct eio_hwmon_dev *eio = drvdata;
+
+	switch (type) {
+	case hwmon_in:
+		return (channel < EIO_MAX_IN && eio->in[channel].available) ? 0444 : 0;
+	case hwmon_curr:
+		return (channel < EIO_MAX_CURR && eio->curr[channel].available) ? 0444 : 0;
+	case hwmon_temp:
+		return (channel < EIO_MAX_TEMP && eio->temp[channel].available) ? 0444 : 0;
+	case hwmon_fan:
+		return (channel < EIO_MAX_FAN && eio->fan[channel].available) ? 0444 : 0;
+	case hwmon_intrusion:
+		return (channel < EIO_MAX_INTRUSION && eio->intrusion.available) ? 0444 : 0;
+	default:
+		return 0;
+	}
+}
+
+static int eio_read(struct device *dev, enum hwmon_sensor_types type,
+		    u32 attr, int channel, long *val)
+{
+	struct eio_hwmon_dev *eio = dev_get_drvdata(dev);
+	u8 data[MAX_CMD_SIZE] = {};
+	enum _sen_type ec_type;
+	u8 item;
+	u32 raw;
+	int ret;
+
+	switch (type) {
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_input:
+			item = EIO_ITEM_INPUT;
+			break;
+		case hwmon_in_max:
+			item = EIO_ITEM_MAX;
+			break;
+		case hwmon_in_min:
+			item = EIO_ITEM_MIN;
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		ec_type = VOLTAGE;
+		break;
+	case hwmon_curr:
+		switch (attr) {
+		case hwmon_curr_input:
+			item = EIO_ITEM_INPUT;
+			break;
+		case hwmon_curr_max:
+			item = EIO_ITEM_MAX;
+			break;
+		case hwmon_curr_min:
+			item = EIO_ITEM_MIN;
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		ec_type = CURRENT;
+		break;
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			item = EIO_ITEM_INPUT;
+			break;
+		case hwmon_temp_max:
+			item = EIO_ITEM_MAX;
+			break;
+		case hwmon_temp_min:
+			item = EIO_ITEM_MIN;
+			break;
+		case hwmon_temp_crit:
+			item = EIO_ITEM_CRIT;
+			break;
+		case hwmon_temp_emergency:
+			item = EIO_ITEM_EMERGENCY;
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		ec_type = TEMP;
+		break;
+	case hwmon_fan:
+		if (attr != hwmon_fan_input)
+			return -EOPNOTSUPP;
+		item = EIO_ITEM_INPUT;
+		ec_type = FAN;
+		break;
+	case hwmon_intrusion:
+		if (attr != hwmon_intrusion_alarm)
+			return -EOPNOTSUPP;
+		item = EIO_ITEM_INPUT;
+		ec_type = CASEOPEN;
+		channel = 0;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	ret = pmc_read(eio->mfd, ec_type, channel, sen_info[ec_type].ctrl[item], data);
+	if (ret)
+		return ret;
+
+	raw = (u32)data[0] | (u32)data[1] << 8 | (u32)data[2] << 16 | (u32)data[3] << 24;
+	*val = ((long)(signed int)raw + sen_info[ec_type].shift) *
+	       (long)sen_info[ec_type].multi[item];
+	return 0;
+}
+
+static int eio_read_string(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, const char **str)
+{
+	struct eio_hwmon_dev *eio = dev_get_drvdata(dev);
+	enum _sen_type ec_type;
+	u8 label_idx;
+
+	switch (type) {
+	case hwmon_in:
+		if (attr != hwmon_in_label)
+			return -EOPNOTSUPP;
+		ec_type = VOLTAGE;
+		label_idx = eio->in[channel].label_idx;
+		break;
+	case hwmon_curr:
+		if (attr != hwmon_curr_label)
+			return -EOPNOTSUPP;
+		ec_type = CURRENT;
+		label_idx = eio->curr[channel].label_idx;
+		break;
+	case hwmon_temp:
+		if (attr != hwmon_temp_label)
+			return -EOPNOTSUPP;
+		ec_type = TEMP;
+		label_idx = eio->temp[channel].label_idx;
+		break;
+	case hwmon_fan:
+		if (attr != hwmon_fan_label)
+			return -EOPNOTSUPP;
+		ec_type = FAN;
+		label_idx = eio->fan[channel].label_idx;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	if (label_idx >= ARRAY_SIZE(sen_info[ec_type].labels))
+		return -EOPNOTSUPP;
+
+	*str = sen_info[ec_type].labels[label_idx];
+	return 0;
+}
+
+static const struct hwmon_ops eio_hwmon_ops = {
+	.is_visible  = eio_is_visible,
+	.read        = eio_read,
+	.read_string = eio_read_string,
+};
+
+static const struct hwmon_channel_info * const eio_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_LABEL | HWMON_I_INPUT | HWMON_I_MAX | HWMON_I_MIN,
+			   HWMON_I_LABEL | HWMON_I_INPUT | HWMON_I_MAX | HWMON_I_MIN,
+			   HWMON_I_LABEL | HWMON_I_INPUT | HWMON_I_MAX | HWMON_I_MIN,
+			   HWMON_I_LABEL | HWMON_I_INPUT | HWMON_I_MAX | HWMON_I_MIN,
+			   HWMON_I_LABEL | HWMON_I_INPUT | HWMON_I_MAX | HWMON_I_MIN,
+			   HWMON_I_LABEL | HWMON_I_INPUT | HWMON_I_MAX | HWMON_I_MIN,
+			   HWMON_I_LABEL | HWMON_I_INPUT | HWMON_I_MAX | HWMON_I_MIN,
+			   HWMON_I_LABEL | HWMON_I_INPUT | HWMON_I_MAX | HWMON_I_MIN),
+	HWMON_CHANNEL_INFO(curr,
+			   HWMON_C_LABEL | HWMON_C_INPUT | HWMON_C_MAX | HWMON_C_MIN,
+			   HWMON_C_LABEL | HWMON_C_INPUT | HWMON_C_MAX | HWMON_C_MIN),
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_CRIT | HWMON_T_EMERGENCY,
+			   HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_CRIT | HWMON_T_EMERGENCY,
+			   HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_CRIT | HWMON_T_EMERGENCY,
+			   HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_CRIT | HWMON_T_EMERGENCY),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_LABEL | HWMON_F_INPUT,
+			   HWMON_F_LABEL | HWMON_F_INPUT,
+			   HWMON_F_LABEL | HWMON_F_INPUT,
+			   HWMON_F_LABEL | HWMON_F_INPUT),
+	HWMON_CHANNEL_INFO(intrusion, HWMON_INTRUSION_ALARM),
+	NULL,
+};
+
+static const struct hwmon_chip_info eio_chip_info = {
+	.ops  = &eio_hwmon_ops,
+	.info = eio_hwmon_info,
+};
+
+static int hwmon_init(struct device *mfd, struct eio_hwmon_dev *eio)
+{
+	enum _sen_type type;
+	u8 i, data[MAX_CMD_SIZE];
+	int n = 0;
+	int ret;
+
+	for (type = VOLTAGE ; type <= TEMP ; type++) {
+		struct eio_chan *chans = (type == VOLTAGE) ? eio->in :
+					(type == CURRENT) ? eio->curr : eio->temp;
+
+		for (i = 0 ; i < sen_info[type].max ; i++) {
+			memset(data, 0, sizeof(data));
+			if (pmc_read(mfd, type, i, 0x00, data) ||
+			    (data[0] & 0x01) == 0)
+				continue;
+
+			memset(data, 0, sizeof(data));
+			ret = pmc_read(mfd, type, i, 0x01, data);
+			if (ret != 0 && ret != -EINVAL)
+				continue;
+
+			chans[i].available = true;
+			chans[i].label_idx = data[0];
+			n++;
+		}
+	}
+
+	for (i = 0 ; i < sen_info[FAN].max ; i++) {
+		memset(data, 0, sizeof(data));
+		if (pmc_read(mfd, FAN, i, 0x00, data) ||
+		    (data[0] & 0x01) == 0)
+			continue;
+
+		memset(data, 0, sizeof(data));
+		ret = pmc_read(mfd, FAN, i, 0x01, data);
+		if (ret != 0 && ret != -EINVAL)
+			continue;
+
+		eio->fan[i].available = true;
+		eio->fan[i].label_idx = data[0];
+		n++;
+	}
+
+	memset(data, 0, sizeof(data));
+	if (!pmc_read(mfd, CASEOPEN, 0, 0x00, data) && (data[0] & 0x01)) {
+		eio->intrusion.available = true;
+		n++;
+	}
+
+	return n;
+}
+
+static int hwmon_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct eio_hwmon_dev *eio;
+	struct eio_dev *eio_dev = dev_get_drvdata(dev->parent);
+	struct device *hwmon;
+
+	if (!eio_dev) {
+		dev_err(dev, "Error contact eio_core\n");
+		return -ENODEV;
+	}
+
+	eio = devm_kzalloc(dev, sizeof(*eio), GFP_KERNEL);
+	if (!eio)
+		return -ENOMEM;
+
+	eio->mfd = dev->parent;
+
+	if (hwmon_init(dev->parent, eio) <= 0)
+		return -ENODEV;
+
+	hwmon = devm_hwmon_device_register_with_info(dev, KBUILD_MODNAME,
+						     eio, &eio_chip_info, NULL);
+	return PTR_ERR_OR_ZERO(hwmon);
+}
+
+static struct platform_driver eio_hwmon_driver = {
+	.probe  = hwmon_probe,
+	.driver = {
+		.name = "eio_hwmon",
+	},
+};
+
+module_platform_driver(eio_hwmon_driver);
+
+MODULE_AUTHOR("Wenkai Chung <wenkai.chung@advantech.com.tw>");
+MODULE_AUTHOR("Ramiro Oliveira <ramiro.oliveira@advantech.com>");
+MODULE_DESCRIPTION("Hardware monitor driver for Advantech EIO embedded controller");
+MODULE_LICENSE("GPL");