This commit adds the driver to control the Advantech EIO Thermal block,
this block is included in the Advantech EIO Embedded Controller.

Signed-off-by: Ramiro Oliveira <ramiro.oliveira@advantech.com>
---
 MAINTAINERS                   |   1 +
 drivers/thermal/Kconfig       |   9 ++
 drivers/thermal/Makefile      |   1 +
 drivers/thermal/eio_thermal.c | 352 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 363 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index dfdf4f39c14b..770b2f82d01a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -623,6 +623,7 @@ F:	drivers/gpio/gpio-eio.c
 F:	drivers/hwmon/eio-hwmon.c
 F:	drivers/i2c/busses/i2c-eio.c
 F:	drivers/mfd/eio_core.c
+F:	drivers/thermal/eio_thermal.c
 F:	drivers/video/backlight/eio_bl.c
 F:	drivers/watchdog/eio_wdt.c
 F:	include/linux/mfd/eio.h
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index b10080d61860..7309f7e7a1c1 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -427,6 +427,15 @@ config DA9062_THERMAL
 	  zone.
 	  Compatible with the DA9062 and DA9061 PMICs.
 
+config EIO_THERMAL
+	tristate "Advantech EIO Thermal zone"
+	depends on MFD_EIO && THERMAL
+	help
+	  Thermal zone support for the Advantech EIO. This driver exposes
+	  temperature readings, trip points and protection enable/disable via
+	  the Linux thermal framework. It communicates with the EC through the
+	  EIO MFD core.
+
 menu "Mediatek thermal drivers"
 depends on ARCH_MEDIATEK || COMPILE_TEST
 source "drivers/thermal/mediatek/Kconfig"
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index bb21e7ea7fc6..3740540d8a18 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_IMX91_THERMAL)	+= imx91_thermal.o
 obj-$(CONFIG_MAX77620_THERMAL)	+= max77620_thermal.o
 obj-$(CONFIG_QORIQ_THERMAL)	+= qoriq_thermal.o
 obj-$(CONFIG_DA9062_THERMAL)	+= da9062-thermal.o
+obj-$(CONFIG_EIO_THERMAL)	+= eio_thermal.o
 obj-y				+= intel/
 obj-$(CONFIG_TI_SOC_THERMAL)	+= ti-soc-thermal/
 obj-y				+= st/
diff --git a/drivers/thermal/eio_thermal.c b/drivers/thermal/eio_thermal.c
new file mode 100644
index 000000000000..2d82bd9d7855
--- /dev/null
+++ b/drivers/thermal/eio_thermal.c
@@ -0,0 +1,352 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * eio_thermal
+ * ================
+ * Thermal zone driver for Advantech EIO embedded controller's thermal
+ * protect mechanism.
+ *
+ * In EIO chip. The smart fan has 3 trips. While the temperature:
+ * - Touch Trip0: Shutdown --> Cut off the power.
+ * - Touch Trip1: Poweroff --> Send the power button signal.
+ * - between Trip2 and Trip1: Throttle --> Intermittently hold the CPU.
+ *
+ *			  PowerOff    Shutdown
+ *			      ^	         ^
+ *	      Throttle	      |		 |
+ *		 |	      |	         |
+ *	+--------+------------+----------+---------
+ *	0       trip2	     trip1      trip0  (Temp)
+ *
+ * Copyright (C) 2025 Advantech Corporation. All rights reserved.
+ */
+
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/eio.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/thermal.h>
+
+#define CMD_THERM_WRITE		 0x10
+#define CMD_THERM_READ		 0x11
+#define THERM_NUM		 0x04
+#define UNIT_PER_TEMP		 100
+
+#define CTRL_STATE		 0x00
+#define CTRL_TYPE		 0x01
+#define CTRL_ERROR		 0x04
+#define CTRL_VALUE		 0x10
+#define CTRL_MAX		 0x11
+#define CTRL_MIN		 0x12
+#define CTRL_THROTTLE		 0x20
+#define CTRL_THROTTLE_HI	 0x21
+#define CTRL_THROTTLE_LO	 0x22
+#define CTRL_THROTTLE_DEFAULT	 0x28
+#define CTRL_THROTTLE_HI_DEFAULT 0x29
+#define CTRL_THROTTLE_LO_DEFAULT 0x2A
+#define CTRL_POWEROFF		 0x30
+#define CTRL_POWEROFF_HI	 0x31
+#define CTRL_POWEROFF_LO	 0x32
+#define CTRL_POWEROFF_DEFAULT	 0x38
+#define CTRL_POWEROFF_HI_DEFAULT 0x39
+#define CTRL_POWEROFF_LO_DEFAULT 0x3A
+#define CTRL_SHUTDOWN		 0x40
+#define CTRL_SHUTDOWN_HI	 0x41
+#define CTRL_SHUTDOWN_LO	 0x42
+#define CTRL_SHUTDOWN_DEFAULT	 0x48
+#define CTRL_SHUTDOWN_HI_DEFAULT 0x49
+#define CTRL_SHUTDOWN_LO_DEFAULT 0x4A
+#define CTRL_SB_TSI_STATUS	 0x80
+#define CTRL_SB_TSI_ACCESS	 0x81
+#define CTRL_WARN_STATUS	 0x90
+#define CTRL_WARN_BEEP		 0x91
+#define CTRL_WARN_TEMP		 0x92
+
+#define THERM_ERR_NO		 0x00
+#define THERM_ERR_CHANNEL	 0x01
+#define THERM_ERR_HI		 0x02
+#define THERM_ERR_LO		 0x03
+
+#define NAME_SIZE		 5
+
+#define TRIP_NUM		 3
+#define TRIP_SHUTDOWN		 0
+#define TRIP_POWEROFF		 1
+#define TRIP_THROTTLE		 2
+/* Beep mechanism no stable. Not supported, yet. */
+#define TRIP_BEEP		 3
+
+#define THERMAL_POLLING_DELAY		2000 /* millisecond */
+#define THERMAL_PASSIVE_DELAY		1000
+
+#define DECI_KELVIN_TO_MILLI_CELSIUS(t) (((t) - 2731) * 100)
+#define MILLI_CELSIUS_TO_DECI_KELVIN(t) (((t) / 100) + 2731)
+
+#define THERM_STS_AVAIL           BIT(0)
+#define THERM_STS_THROTTLE_AVAIL  BIT(1)
+#define THERM_STS_POWEROFF_AVAIL  BIT(2)
+#define THERM_STS_SHUTDOWN_AVAIL  BIT(3)
+#define THERM_STS_THROTTLE_EVT    BIT(4)
+#define THERM_STS_POWEROFF_EVT    BIT(5)
+#define THERM_STS_SHUTDOWN_EVT    BIT(6)
+/* BIT(7) reserved */
+#define THERM_STS_THROTTLE_ON     BIT(8)
+#define THERM_STS_POWEROFF_ON     BIT(9)
+#define THERM_STS_SHUTDOWN_ON     BIT(10)
+/* BIT(11) reserved */
+#define THERM_STS_THROTTLE_LOG    BIT(12)
+#define THERM_STS_POWEROFF_LOG    BIT(13)
+#define THERM_STS_SHUTDOWN_LOG    BIT(14)
+
+static u8 pmc_len[] = {
+/*      0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f */
+/* 0 */	2, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+/* 1 */	2, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+/* 2 */	1, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+/* 3 */	1, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+/* 4 */	1, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+/* 5 */	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+/* 6 */	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+/* 7 */	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+/* 8 */	1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+/* 9 */	2, 1, 2,
+};
+
+static char therm_name[0x20][NAME_SIZE + 1] = {
+	"CPU0", "CPU1", "CPU2", "CPU3", "SYS0", "SYS1", "SYS2", "SYS3",
+	"AUX0", "AUX1", "AUX2", "AUX3", "DIMM0", "DIMM1", "DIMM2", "DIMM3",
+	"PCH", "VGA", "", "", "", "", "", "",
+	"", "", "", "", "OEM0", "OEM1", "OEM2", "OEM3",
+};
+
+static const u8 ctrl_map[] = {
+	CTRL_SHUTDOWN, CTRL_POWEROFF, CTRL_THROTTLE
+};
+
+struct eio_thermal_dev {
+	struct device *mfd;
+	struct device *dev;
+	u8 ch;
+	u8 name;
+};
+
+struct eio_trip_dev {
+	struct device *mfd;
+	u8 ch;
+	u8 idx;
+};
+
+static int timeout;
+module_param(timeout, int, 0444);
+MODULE_PARM_DESC(timeout, "Set PMC command timeout value.\n");
+
+static int pmc_write(struct device *mfd, u8 ctrl, u8 dev_id, void *data)
+{
+	if (ctrl >= ARRAY_SIZE(pmc_len))
+		return -EINVAL;
+
+	struct pmc_op op = {
+		.cmd       = CMD_THERM_WRITE,
+		.control   = ctrl,
+		.device_id = dev_id,
+		.payload   = (u8 *)data,
+		.size      = pmc_len[ctrl],
+		.timeout   = timeout,
+	};
+
+	return eio_core_pmc_operation(mfd, &op);
+}
+
+static int pmc_read(struct device *mfd, u8 ctrl, u8 dev_id, void *data)
+{
+	if (ctrl >= ARRAY_SIZE(pmc_len))
+		return -EINVAL;
+
+	struct pmc_op op = {
+		.cmd       = CMD_THERM_READ,
+		.control   = ctrl,
+		.device_id = dev_id,
+		.payload   = (u8 *)data,
+		.size      = pmc_len[ctrl],
+		.timeout   = timeout,
+	};
+
+	return eio_core_pmc_operation(mfd, &op);
+}
+
+static int eio_tz_get_temp(struct thermal_zone_device *tzd, int *temp)
+{
+	struct eio_thermal_dev *eio_thermal = thermal_zone_device_priv(tzd);
+	u16 val = 0;
+	int ret;
+
+	ret = pmc_read(eio_thermal->mfd, CTRL_VALUE, eio_thermal->ch, &val);
+	if (ret)
+		return ret;
+
+	*temp = DECI_KELVIN_TO_MILLI_CELSIUS(val);
+	return 0;
+}
+
+static int eio_tz_set_trip_temp(struct thermal_zone_device *tzd,
+				const struct thermal_trip *trip, int temp)
+{
+	struct eio_thermal_dev *eio_thermal = thermal_zone_device_priv(tzd);
+	const u8 ctl = (uintptr_t)trip->priv;
+	u16 val;
+
+	if (temp < 1000)
+		return -EINVAL;
+
+	val = MILLI_CELSIUS_TO_DECI_KELVIN(temp);
+	return pmc_write(eio_thermal->mfd, ctl, eio_thermal->ch, &val);
+}
+
+static int eio_tz_change_mode(struct thermal_zone_device *tzd,
+			      enum thermal_device_mode mode)
+{
+	struct eio_thermal_dev *eio_thermal = thermal_zone_device_priv(tzd);
+	int trip;
+	int ret = 0;
+
+	for (trip = 0; trip < TRIP_NUM; trip++) {
+		ret = pmc_write(eio_thermal->mfd, ctrl_map[trip], eio_thermal->ch, &mode);
+		if (ret)
+			dev_err(eio_thermal->dev, "Error when %s trip num %d\n",
+				mode == THERMAL_DEVICE_ENABLED ? "enabling" : "disabling",
+				trip);
+	}
+
+	return ret;
+}
+
+static struct thermal_zone_device_ops zone_ops = {
+	.get_temp = eio_tz_get_temp,
+	.set_trip_temp = eio_tz_set_trip_temp,
+	.change_mode   = eio_tz_change_mode,
+};
+
+static struct thermal_zone_params zone_params = {
+	.no_hwmon      = true,
+};
+
+static int eio_thermal_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int ch;
+
+	if (!dev_get_drvdata(dev->parent)) {
+		dev_err(dev, "eio_core not present\n");
+		return -ENODEV;
+	}
+
+	for (ch = 0; ch < THERM_NUM; ch++) {
+		u16 state = 0;
+		u8  name  = 0;
+		u16 hi_shutdown = 0, hi_poweroff = 0, hi_throttle = 0;
+		int t_shutdown = 0, t_poweroff = 0, t_throttle = 0;
+		struct thermal_trip trips[TRIP_NUM];
+		int ntrips = 0;
+		struct eio_thermal_dev *eio_th;
+		struct thermal_zone_device *tzd;
+
+		if (pmc_read(dev->parent, CTRL_STATE, (u8)ch, &state) ||
+		    pmc_read(dev->parent, CTRL_TYPE,  (u8)ch, &name)) {
+			dev_info(dev, "thermal%d: PMC read error\n", ch);
+			continue;
+		}
+
+		if (!(state & THERM_STS_AVAIL) ||
+		    !((state & THERM_STS_THROTTLE_AVAIL) ||
+		      (state & THERM_STS_POWEROFF_AVAIL) ||
+		      (state & THERM_STS_SHUTDOWN_AVAIL))) {
+			dev_info(dev, "thermal%d: firmware not activated\n", ch);
+			continue;
+		}
+
+		if (name >= ARRAY_SIZE(therm_name) || !therm_name[name][0]) {
+			dev_info(dev, "thermal%d: unknown sensor name idx=%u\n", ch, name);
+			continue;
+		}
+
+		/* Throttle starts a 1C increase it */
+		int throttle_temp = MILLI_CELSIUS_TO_DECI_KELVIN(60000);
+
+		pmc_write(dev->parent, CTRL_THROTTLE_HI, (u8)ch, &throttle_temp);
+
+		pmc_read(dev->parent, CTRL_SHUTDOWN_HI, (u8)ch, &hi_shutdown);
+		pmc_read(dev->parent, CTRL_POWEROFF_HI, (u8)ch, &hi_poweroff);
+		pmc_read(dev->parent, CTRL_THROTTLE_HI, (u8)ch, &hi_throttle);
+
+		t_shutdown = DECI_KELVIN_TO_MILLI_CELSIUS(hi_shutdown);
+		t_poweroff = DECI_KELVIN_TO_MILLI_CELSIUS(hi_poweroff);
+		t_throttle = DECI_KELVIN_TO_MILLI_CELSIUS(hi_throttle);
+
+		ntrips = 0;
+		if (hi_shutdown) {
+			trips[ntrips].type = THERMAL_TRIP_CRITICAL;
+			trips[ntrips].temperature = t_shutdown;
+			trips[ntrips].flags = THERMAL_TRIP_FLAG_RW_TEMP;
+			trips[ntrips].priv  = THERMAL_INT_TO_TRIP_PRIV(TRIP_SHUTDOWN),
+			ntrips++;
+		}
+		if (hi_poweroff) {
+			trips[ntrips].type = THERMAL_TRIP_HOT;
+			trips[ntrips].temperature = t_poweroff;
+			trips[ntrips].flags = THERMAL_TRIP_FLAG_RW_TEMP;
+			trips[ntrips].priv  = THERMAL_INT_TO_TRIP_PRIV(TRIP_POWEROFF),
+			ntrips++;
+		}
+		if (hi_throttle) {
+			trips[ntrips].type = THERMAL_TRIP_PASSIVE;
+			trips[ntrips].temperature = t_throttle;
+			trips[ntrips].flags = THERMAL_TRIP_FLAG_RW_TEMP;
+			trips[ntrips].priv  = THERMAL_INT_TO_TRIP_PRIV(TRIP_THROTTLE),
+			ntrips++;
+		}
+		if (!ntrips) {
+			dev_info(dev, "thermal%d: no valid trips\n", ch);
+			continue;
+		}
+
+		eio_th = devm_kzalloc(dev, sizeof(*eio_th), GFP_KERNEL);
+		if (!eio_th)
+			return -ENOMEM;
+		eio_th->ch = (u8)ch;
+		eio_th->mfd = dev->parent;
+		eio_th->dev = dev;
+
+		tzd = thermal_zone_device_register_with_trips(therm_name[name],
+							      trips,
+							      ntrips,
+							      eio_th,
+							      &zone_ops,
+							      &zone_params,
+							      THERMAL_PASSIVE_DELAY,
+							      THERMAL_POLLING_DELAY);
+		if (IS_ERR(tzd))
+			return PTR_ERR(tzd);
+		/* Make sure zones start disabled */
+		thermal_zone_device_disable(tzd);
+
+		dev_info(dev, "%s thermal up (ch=%d)\n", therm_name[name], ch);
+	}
+
+	return 0;
+}
+
+static struct platform_driver eio_thermal_driver = {
+	.probe  = eio_thermal_probe,
+	.driver = {
+		.name = "eio_thermal",
+	},
+};
+module_platform_driver(eio_thermal_driver);
+
+MODULE_AUTHOR("Wenkai Chung <wenkai.chung@advantech.com.tw>");
+MODULE_AUTHOR("Ramiro Oliveira <ramiro.oliveira@advantech.com>");
+MODULE_DESCRIPTION("Thermal driver for Advantech EIO embedded controller");
+MODULE_LICENSE("GPL");

-- 
2.43.0