hwmon: Add EC Chip driver for Lenovo ThinkStation motherboards

This addition adds in the ability for the system to scan
the EC chip in the Lenovo ThinkStation systems to get the
current fan RPM speeds the Maximum speed value for each
fan also provides the CPU, DIMM other thermal statuses

Signed-off-by: David Ober <dober6023@gmail.com>
Link: https://lore.kernel.org/r/20240328121250.331146-1-dober6023@gmail.com
[groeck: Dropped pointless case statements]
[Colin King: Fixed spelling error accesssible -> accessible]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

3 files changed, 613 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index c89776d91795ba..bafc0058c728f5 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -917,6 +917,16 @@ config SENSORS_LAN966X
 	  This driver can also be built as a module. If so, the module
 	  will be called lan966x-hwmon.
 
+config SENSORS_LENOVO_EC
+        tristate "Sensor reader for Lenovo ThinkStations"
+        depends on X86
+        help
+          If you say yes here you get support for LENOVO
+          EC Sensor data on newer ThinkStation systems
+
+          This driver can also be built as a module. If so, the module
+          will be called lenovo_ec_sensors.
+
 config SENSORS_LINEAGE
 	tristate "Lineage Compact Power Line Power Entry Module"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 5c31808f6378d9..e3f25475d1f043 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -108,6 +108,7 @@ obj-$(CONFIG_SENSORS_JC42)	+= jc42.o
 obj-$(CONFIG_SENSORS_K8TEMP)	+= k8temp.o
 obj-$(CONFIG_SENSORS_K10TEMP)	+= k10temp.o
 obj-$(CONFIG_SENSORS_LAN966X)	+= lan966x-hwmon.o
+obj-$(CONFIG_SENSORS_LENOVO_EC)	+= lenovo-ec-sensors.o
 obj-$(CONFIG_SENSORS_LINEAGE)	+= lineage-pem.o
 obj-$(CONFIG_SENSORS_LOCHNAGAR)	+= lochnagar-hwmon.o
 obj-$(CONFIG_SENSORS_LM63)	+= lm63.o
diff --git a/drivers/hwmon/lenovo-ec-sensors.c b/drivers/hwmon/lenovo-ec-sensors.c
new file mode 100644
index 00000000000000..143fb79713f7d3
--- /dev/null
+++ b/drivers/hwmon/lenovo-ec-sensors.c
@@ -0,0 +1,602 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * HWMON driver for Lenovo ThinkStation based workstations
+ * via the embedded controller registers
+ *
+ * Copyright (C) 2024 David Ober (Lenovo) <dober@lenovo.com>
+ *
+ * EC provides:
+ * - CPU temperature
+ * - DIMM temperature
+ * - Chassis zone temperatures
+ * - CPU fan RPM
+ * - DIMM fan RPM
+ * - Chassis fans RPM
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/acpi.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dmi.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/units.h>
+
+#define MCHP_SING_IDX			0x0000
+#define MCHP_EMI0_APPLICATION_ID	0x090C
+#define MCHP_EMI0_EC_ADDRESS		0x0902
+#define MCHP_EMI0_EC_DATA_BYTE0		0x0904
+#define MCHP_EMI0_EC_DATA_BYTE1		0x0905
+#define MCHP_EMI0_EC_DATA_BYTE2		0x0906
+#define MCHP_EMI0_EC_DATA_BYTE3		0x0907
+#define IO_REGION_START			0x0900
+#define IO_REGION_LENGTH		0xD
+
+static inline u8
+get_ec_reg(unsigned char page, unsigned char index)
+{
+	u8 onebyte;
+	unsigned short m_index;
+	unsigned short phy_index = page * 256 + index;
+
+	outb_p(0x01, MCHP_EMI0_APPLICATION_ID);
+
+	m_index = phy_index & GENMASK(14, 2);
+	outw_p(m_index, MCHP_EMI0_EC_ADDRESS);
+
+	onebyte = inb_p(MCHP_EMI0_EC_DATA_BYTE0 + (phy_index & GENMASK(1, 0)));
+
+	outb_p(0x01, MCHP_EMI0_APPLICATION_ID);  /* write 0x01 again to clean */
+	return onebyte;
+}
+
+enum systems {
+	LENOVO_PX,
+	LENOVO_P7,
+	LENOVO_P5,
+	LENOVO_P8,
+};
+
+static int px_temp_map[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
+
+static const char * const lenovo_px_ec_temp_label[] = {
+	"CPU1",
+	"CPU2",
+	"R_DIMM1",
+	"L_DIMM1",
+	"R_DIMM2",
+	"L_DIMM2",
+	"PCH",
+	"M2_R",
+	"M2_Z1R",
+	"M2_Z2R",
+	"PCI_Z1",
+	"PCI_Z2",
+	"PCI_Z3",
+	"PCI_Z4",
+	"AMB",
+};
+
+static int gen_temp_map[] = {0, 2, 3, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
+
+static const char * const lenovo_gen_ec_temp_label[] = {
+	"CPU1",
+	"R_DIMM",
+	"L_DIMM",
+	"PCH",
+	"M2_R",
+	"M2_Z1R",
+	"M2_Z2R",
+	"PCI_Z1",
+	"PCI_Z2",
+	"PCI_Z3",
+	"PCI_Z4",
+	"AMB",
+};
+
+static int px_fan_map[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
+
+static const char * const px_ec_fan_label[] = {
+	"CPU1_Fan",
+	"CPU2_Fan",
+	"Front_Fan1-1",
+	"Front_Fan1-2",
+	"Front_Fan2",
+	"Front_Fan3",
+	"MEM_Fan1",
+	"MEM_Fan2",
+	"Rear_Fan1",
+	"Rear_Fan2",
+	"Flex_Bay_Fan1",
+	"Flex_Bay_Fan2",
+	"Flex_Bay_Fan2",
+	"PSU_HDD_Fan",
+	"PSU1_Fan",
+	"PSU2_Fan",
+};
+
+static int p7_fan_map[] = {0, 2, 3, 4, 5, 6, 7, 8, 10, 11, 14};
+
+static const char * const p7_ec_fan_label[] = {
+	"CPU1_Fan",
+	"HP_CPU_Fan1",
+	"HP_CPU_Fan2",
+	"PCIE1_4_Fan",
+	"PCIE5_7_Fan",
+	"MEM_Fan1",
+	"MEM_Fan2",
+	"Rear_Fan1",
+	"BCB_Fan",
+	"Flex_Bay_Fan",
+	"PSU_Fan",
+};
+
+static int p5_fan_map[] = {0, 5, 6, 7, 8, 10, 11, 14};
+
+static const char * const p5_ec_fan_label[] = {
+	"CPU_Fan",
+	"HDD_Fan",
+	"Duct_Fan1",
+	"MEM_Fan",
+	"Rear_Fan",
+	"Front_Fan",
+	"Flex_Bay_Fan",
+	"PSU_Fan",
+};
+
+static int p8_fan_map[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14};
+
+static const char * const p8_ec_fan_label[] = {
+	"CPU1_Fan",
+	"CPU2_Fan",
+	"HP_CPU_Fan1",
+	"HP_CPU_Fan2",
+	"PCIE1_4_Fan",
+	"PCIE5_7_Fan",
+	"DIMM1_Fan1",
+	"DIMM1_Fan2",
+	"DIMM2_Fan1",
+	"DIMM2_Fan2",
+	"Rear_Fan",
+	"HDD_Bay_Fan",
+	"Flex_Bay_Fan",
+	"PSU_Fan",
+};
+
+struct ec_sensors_data {
+	struct mutex mec_mutex; /* lock for sensor data access */
+	const char *const *fan_labels;
+	const char *const *temp_labels;
+	const int *fan_map;
+	const int *temp_map;
+};
+
+static int
+lenovo_ec_do_read_temp(struct ec_sensors_data *data, u32 attr, int channel, long *val)
+{
+	u8 lsb;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		mutex_lock(&data->mec_mutex);
+		lsb = get_ec_reg(2, 0x81 + channel);
+		mutex_unlock(&data->mec_mutex);
+		if (lsb <= 0x40)
+			return -ENODATA;
+		*val = (lsb - 0x40) * 1000;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int
+lenovo_ec_do_read_fan(struct ec_sensors_data *data, u32 attr, int channel, long *val)
+{
+	u8 lsb, msb;
+
+	channel *= 2;
+	switch (attr) {
+	case hwmon_fan_input:
+		mutex_lock(&data->mec_mutex);
+		lsb = get_ec_reg(4, 0x20 + channel);
+		msb = get_ec_reg(4, 0x21 + channel);
+		mutex_unlock(&data->mec_mutex);
+		*val = (msb << 8) + lsb;
+		return 0;
+	case hwmon_fan_max:
+		mutex_lock(&data->mec_mutex);
+		lsb = get_ec_reg(4, 0x40 + channel);
+		msb = get_ec_reg(4, 0x41 + channel);
+		mutex_unlock(&data->mec_mutex);
+		*val = (msb << 8) + lsb;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int
+lenovo_ec_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
+			    u32 attr, int channel, const char **str)
+{
+	struct ec_sensors_data *state = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_temp:
+		*str = state->temp_labels[channel];
+		return 0;
+	case hwmon_fan:
+		*str = state->fan_labels[channel];
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int
+lenovo_ec_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+		     u32 attr, int channel, long *val)
+{
+	struct ec_sensors_data *data = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_temp:
+		return lenovo_ec_do_read_temp(data, attr, data->temp_map[channel], val);
+	case hwmon_fan:
+		return lenovo_ec_do_read_fan(data, attr, data->fan_map[channel], val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static umode_t
+lenovo_ec_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
+			   u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_temp:
+		if (attr == hwmon_temp_input || attr == hwmon_temp_label)
+			return 0444;
+		return 0;
+	case hwmon_fan:
+		if (attr == hwmon_fan_input || attr == hwmon_fan_max || attr == hwmon_fan_label)
+			return 0444;
+		return 0;
+	default:
+		return 0;
+	}
+}
+
+static const struct hwmon_channel_info *lenovo_ec_hwmon_info_px[] = {
+	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_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_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX),
+	NULL
+};
+
+static const struct hwmon_channel_info *lenovo_ec_hwmon_info_p8[] = {
+	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_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX),
+	NULL
+};
+
+static const struct hwmon_channel_info *lenovo_ec_hwmon_info_p7[] = {
+	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_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX),
+	NULL
+};
+
+static const struct hwmon_channel_info *lenovo_ec_hwmon_info_p5[] = {
+	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_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX),
+	NULL
+};
+
+static const struct hwmon_ops lenovo_ec_hwmon_ops = {
+	.is_visible = lenovo_ec_hwmon_is_visible,
+	.read = lenovo_ec_hwmon_read,
+	.read_string = lenovo_ec_hwmon_read_string,
+};
+
+static struct hwmon_chip_info lenovo_ec_chip_info = {
+	.ops = &lenovo_ec_hwmon_ops,
+};
+
+static const struct dmi_system_id thinkstation_dmi_table[] = {
+	{
+		.ident = "LENOVO_PX",
+		.driver_data = (void *)(long)LENOVO_PX,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "30EU"),
+		},
+	},
+	{
+		.ident = "LENOVO_PX",
+		.driver_data = (void *)(long)LENOVO_PX,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "30EV"),
+		},
+	},
+	{
+		.ident = "LENOVO_P7",
+		.driver_data = (void *)(long)LENOVO_P7,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "30F2"),
+		},
+	},
+	{
+		.ident = "LENOVO_P7",
+		.driver_data = (void *)(long)LENOVO_P7,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "30F3"),
+		},
+	},
+	{
+		.ident = "LENOVO_P5",
+		.driver_data = (void *)(long)LENOVO_P5,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "30G9"),
+		},
+	},
+	{
+		.ident = "LENOVO_P5",
+		.driver_data = (void *)(long)LENOVO_P5,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "30GA"),
+		},
+	},
+	{
+		.ident = "LENOVO_P8",
+		.driver_data = (void *)(long)LENOVO_P8,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "30HH"),
+		},
+	},
+	{
+		.ident = "LENOVO_P8",
+		.driver_data = (void *)(long)LENOVO_P8,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "30HJ"),
+		},
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(dmi, thinkstation_dmi_table);
+
+static int lenovo_ec_probe(struct platform_device *pdev)
+{
+	struct device *hwdev;
+	struct ec_sensors_data *ec_data;
+	const struct hwmon_chip_info *chip_info;
+	struct device *dev = &pdev->dev;
+	const struct dmi_system_id *dmi_id;
+	int app_id;
+
+	ec_data = devm_kzalloc(dev, sizeof(struct ec_sensors_data), GFP_KERNEL);
+	if (!ec_data)
+		return -ENOMEM;
+
+	if (!request_region(IO_REGION_START, IO_REGION_LENGTH, "LNV-WKS")) {
+		pr_err(":request fail\n");
+		return -EIO;
+	}
+
+	dev_set_drvdata(dev, ec_data);
+
+	chip_info = &lenovo_ec_chip_info;
+
+	mutex_init(&ec_data->mec_mutex);
+
+	mutex_lock(&ec_data->mec_mutex);
+	app_id = inb_p(MCHP_EMI0_APPLICATION_ID);
+	if (app_id) /* check EMI Application ID Value */
+		outb_p(app_id, MCHP_EMI0_APPLICATION_ID); /* set EMI Application ID to 0 */
+	outw_p(MCHP_SING_IDX, MCHP_EMI0_EC_ADDRESS);
+	mutex_unlock(&ec_data->mec_mutex);
+
+	if ((inb_p(MCHP_EMI0_EC_DATA_BYTE0) != 'M') &&
+	    (inb_p(MCHP_EMI0_EC_DATA_BYTE1) != 'C') &&
+	    (inb_p(MCHP_EMI0_EC_DATA_BYTE2) != 'H') &&
+	    (inb_p(MCHP_EMI0_EC_DATA_BYTE3) != 'P')) {
+		release_region(IO_REGION_START, IO_REGION_LENGTH);
+		return -ENODEV;
+	}
+
+	dmi_id = dmi_first_match(thinkstation_dmi_table);
+
+	switch ((long)dmi_id->driver_data) {
+	case 0:
+		ec_data->fan_labels = px_ec_fan_label;
+		ec_data->temp_labels = lenovo_px_ec_temp_label;
+		ec_data->fan_map = px_fan_map;
+		ec_data->temp_map = px_temp_map;
+		lenovo_ec_chip_info.info = lenovo_ec_hwmon_info_px;
+		break;
+	case 1:
+		ec_data->fan_labels = p7_ec_fan_label;
+		ec_data->temp_labels = lenovo_gen_ec_temp_label;
+		ec_data->fan_map = p7_fan_map;
+		ec_data->temp_map = gen_temp_map;
+		lenovo_ec_chip_info.info = lenovo_ec_hwmon_info_p7;
+		break;
+	case 2:
+		ec_data->fan_labels = p5_ec_fan_label;
+		ec_data->temp_labels = lenovo_gen_ec_temp_label;
+		ec_data->fan_map = p5_fan_map;
+		ec_data->temp_map = gen_temp_map;
+		lenovo_ec_chip_info.info = lenovo_ec_hwmon_info_p5;
+		break;
+	case 3:
+		ec_data->fan_labels = p8_ec_fan_label;
+		ec_data->temp_labels = lenovo_gen_ec_temp_label;
+		ec_data->fan_map = p8_fan_map;
+		ec_data->temp_map = gen_temp_map;
+		lenovo_ec_chip_info.info = lenovo_ec_hwmon_info_p8;
+		break;
+	default:
+		release_region(IO_REGION_START, IO_REGION_LENGTH);
+		return -ENODEV;
+	}
+
+	hwdev = devm_hwmon_device_register_with_info(dev, "lenovo_ec",
+						     ec_data,
+						     chip_info, NULL);
+
+	return PTR_ERR_OR_ZERO(hwdev);
+}
+
+static struct platform_driver lenovo_ec_sensors_platform_driver = {
+	.driver = {
+		.name	= "lenovo-ec-sensors",
+	},
+	.probe = lenovo_ec_probe,
+};
+
+static struct platform_device *lenovo_ec_sensors_platform_device;
+
+static int __init lenovo_ec_init(void)
+{
+	if (!dmi_check_system(thinkstation_dmi_table))
+		return -ENODEV;
+
+	lenovo_ec_sensors_platform_device =
+		platform_create_bundle(&lenovo_ec_sensors_platform_driver,
+				       lenovo_ec_probe, NULL, 0, NULL, 0);
+
+	if (IS_ERR(lenovo_ec_sensors_platform_device)) {
+		release_region(IO_REGION_START, IO_REGION_LENGTH);
+		return PTR_ERR(lenovo_ec_sensors_platform_device);
+	}
+
+	return 0;
+}
+module_init(lenovo_ec_init);
+
+static void __exit lenovo_ec_exit(void)
+{
+	release_region(IO_REGION_START, IO_REGION_LENGTH);
+	platform_device_unregister(lenovo_ec_sensors_platform_device);
+	platform_driver_unregister(&lenovo_ec_sensors_platform_driver);
+}
+module_exit(lenovo_ec_exit);
+
+MODULE_AUTHOR("David Ober <dober@lenovo.com>");
+MODULE_DESCRIPTION("HWMON driver for sensors accessible via EC in LENOVO motherboards");
+MODULE_LICENSE("GPL");