Merge tag 'ib-mfd-hwmon-v5.8' into hwmon-next

Immutable branch between MFD and HWMON due for the v5.8 merge window

Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/gateworks-gsc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Gateworks System Controller
+
+description: |
+  The Gateworks System Controller (GSC) is a device present across various
+  Gateworks product families that provides a set of system related features
+  such as the following (refer to the board hardware user manuals to see what
+  features are present)
+   - Watchdog Timer
+   - GPIO
+   - Pushbutton controller
+   - Hardware monitor with ADC's for temperature and voltage rails and
+     fan controller
+
+maintainers:
+  - Tim Harvey <tharvey@gateworks.com>
+  - Robert Jones <rjones@gateworks.com>
+
+properties:
+  $nodename:
+    pattern: "gsc@[0-9a-f]{1,2}"
+  compatible:
+    const: gw,gsc
+
+  reg:
+    description: I2C device address
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  adc:
+    type: object
+    description: Optional hardware monitoring module
+
+    properties:
+      compatible:
+        const: gw,gsc-adc
+
+      "#address-cells":
+        const: 1
+
+      "#size-cells":
+        const: 0
+
+    patternProperties:
+      "^channel@[0-9]+$":
+        type: object
+        description: |
+          Properties for a single ADC which can report cooked values
+          (i.e. temperature sensor based on thermister), raw values
+          (i.e. voltage rail with a pre-scaling resistor divider).
+
+        properties:
+          reg:
+            description: Register of the ADC
+            maxItems: 1
+
+          label:
+            description: Name of the ADC input
+
+          gw,mode:
+            description: |
+              conversion mode:
+                0 - temperature, in C*10
+                1 - pre-scaled voltage value
+                2 - scaled voltage based on an optional resistor divider
+                    and optional offset
+            $ref: /schemas/types.yaml#/definitions/uint32
+            enum: [0, 1, 2]
+
+          gw,voltage-divider-ohms:
+            description: Values of resistors for divider on raw ADC input
+            maxItems: 2
+            items:
+             minimum: 1000
+             maximum: 1000000
+
+          gw,voltage-offset-microvolt:
+            description: |
+              A positive voltage offset to apply to a raw ADC
+              (i.e. to compensate for a diode drop).
+            minimum: 0
+            maximum: 1000000
+
+        required:
+          - gw,mode
+          - reg
+          - label
+
+    required:
+      - compatible
+      - "#address-cells"
+      - "#size-cells"
+
+patternProperties:
+  "^fan-controller@[0-9a-f]+$":
+    type: object
+    description: Optional fan controller
+
+    properties:
+      compatible:
+        const: gw,gsc-fan
+
+      "#address-cells":
+        const: 1
+
+      "#size-cells":
+        const: 0
+
+      reg:
+        description: The fan controller base address
+        maxItems: 1
+
+    required:
+      - compatible
+      - reg
+      - "#address-cells"
+      - "#size-cells"
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - "#interrupt-cells"
+  - "#address-cells"
+  - "#size-cells"
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        gsc@20 {
+            compatible = "gw,gsc";
+            reg = <0x20>;
+            interrupt-parent = <&gpio1>;
+            interrupts = <4 GPIO_ACTIVE_LOW>;
+            interrupt-controller;
+            #interrupt-cells = <1>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            adc {
+                compatible = "gw,gsc-adc";
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                channel@0 { /* A0: Board Temperature */
+                    reg = <0x00>;
+                    label = "temp";
+                    gw,mode = <0>;
+                };
+
+                channel@2 { /* A1: Input Voltage (raw ADC) */
+                    reg = <0x02>;
+                    label = "vdd_vin";
+                    gw,mode = <1>;
+                    gw,voltage-divider-ohms = <22100 1000>;
+                    gw,voltage-offset-microvolt = <800000>;
+                };
+
+                channel@b { /* A2: Battery voltage */
+                    reg = <0x0b>;
+                    label = "vdd_bat";
+                    gw,mode = <1>;
+                };
+            };
+
+            fan-controller@2c {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                compatible = "gw,gsc-fan";
+                reg = <0x2c>;
+            };
+        };
+    };

Documentation/hwmon/gsc-hwmon.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver gsc-hwmon
+=======================
+
+Supported chips: Gateworks GSC
+Datasheet: http://trac.gateworks.com/wiki/gsc
+Author: Tim Harvey <tharvey@gateworks.com>
+
+Description:
+------------
+
+This driver supports hardware monitoring for the temperature sensor,
+various ADC's connected to the GSC, and optional FAN controller available
+on some boards.
+
+
+Voltage Monitoring
+------------------
+
+The voltage inputs are scaled either internally or by the driver depending
+on the GSC version and firmware. The values returned by the driver do not need
+further scaling. The voltage input labels provide the voltage rail name:
+
+inX_input                  Measured voltage (mV).
+inX_label                  Name of voltage rail.
+
+
+Temperature Monitoring
+----------------------
+
+Temperatures are measured with 12-bit or 10-bit resolution and are scaled
+either internally or by the driver depending on the GSC version and firmware.
+The values returned by the driver reflect millidegree Celcius:
+
+tempX_input                Measured temperature.
+tempX_label                Name of temperature input.
+
+
+PWM Output Control
+------------------
+
+The GSC features 1 PWM output that operates in automatic mode where the
+PWM value will be scalled depending on 6 temperature boundaries.
+The tempeature boundaries are read-write and in millidegree Celcius and the
+read-only PWM values range from 0 (off) to 255 (full speed).
+Fan speed will be set to minimum (off) when the temperature sensor reads
+less than pwm1_auto_point1_temp and maximum when the temperature sensor
+equals or exceeds pwm1_auto_point6_temp.
+
+pwm1_auto_point[1-6]_pwm       PWM value.
+pwm1_auto_point[1-6]_temp      Temperature boundary.
+

Documentation/hwmon/index.rst

@@ -61,6 +61,7 @@ Hardware Monitoring Kernel Drivers
    ftsteutates
    g760a
    g762
+   gsc-hwmon
    gl518sm
    hih6130
    ibmaem

MAINTAINERS

@@ -7035,6 +7035,17 @@ F:	kernel/futex.c
 F:	tools/perf/bench/futex*
 F:	tools/testing/selftests/futex/
 
+GATEWORKS SYSTEM CONTROLLER (GSC) DRIVER
+M:	Tim Harvey <tharvey@gateworks.com>
+M:	Robert Jones <rjones@gateworks.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
+F:	drivers/mfd/gateworks-gsc.c
+F:	include/linux/mfd/gsc.h
+F:	Documentation/hwmon/gsc-hwmon.rst
+F:	drivers/hwmon/gsc-hwmon.c
+F:	include/linux/platform_data/gsc_hwmon.h
+
 GASKET DRIVER FRAMEWORK
 M:	Rob Springer <rspringer@google.com>
 M:	Todd Poynor <toddpoynor@google.com>

drivers/hwmon/Kconfig

@@ -533,6 +533,15 @@ config SENSORS_F75375S
 	  This driver can also be built as a module. If so, the module
 	  will be called f75375s.
 
+config SENSORS_GSC
+	tristate "Gateworks System Controller ADC"
+	depends on MFD_GATEWORKS_GSC
+	help
+	  Support for the Gateworks System Controller A/D converters.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called gsc-hwmon.
+
 config SENSORS_MC13783_ADC
         tristate "Freescale MC13783/MC13892 ADC"
         depends on MFD_MC13XXX

drivers/hwmon/Makefile

@@ -75,6 +75,7 @@ obj-$(CONFIG_SENSORS_G760A)	+= g760a.o
 obj-$(CONFIG_SENSORS_G762)	+= g762.o
 obj-$(CONFIG_SENSORS_GL518SM)	+= gl518sm.o
 obj-$(CONFIG_SENSORS_GL520SM)	+= gl520sm.o
+obj-$(CONFIG_SENSORS_GSC)	+= gsc-hwmon.o
 obj-$(CONFIG_SENSORS_GPIO_FAN)	+= gpio-fan.o
 obj-$(CONFIG_SENSORS_HIH6130)	+= hih6130.o
 obj-$(CONFIG_SENSORS_ULTRA45)	+= ultra45_env.o

drivers/mfd/Kconfig

@@ -407,6 +407,21 @@ config MFD_EXYNOS_LPASS
 	  Select this option to enable support for Samsung Exynos Low Power
 	  Audio Subsystem.
 
+config MFD_GATEWORKS_GSC
+	tristate "Gateworks System Controller"
+	depends on (I2C && OF)
+	select MFD_CORE
+	select REGMAP_I2C
+	select REGMAP_IRQ
+	help
+	  Enable support for the Gateworks System Controller (GSC) found
+	  on Gateworks Single Board Computers supporting system functions
+	  such as push-button monitor, multiple ADC's for voltage and
+	  temperature monitoring, fan controller and watchdog monitor.
+	  This driver provides common support for accessing the device.
+	  Additional drivers must be enabled in order to use the
+	  functionality of the device.
+
 config MFD_MC13XXX
 	tristate
 	depends on (SPI_MASTER || I2C)

drivers/mfd/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
 obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
 obj-$(CONFIG_MFD_CROS_EC_DEV)	+= cros_ec_dev.o
 obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
+obj-$(CONFIG_MFD_GATEWORKS_GSC)	+= gateworks-gsc.o
 
 obj-$(CONFIG_HTC_PASIC3)	+= htc-pasic3.o
 obj-$(CONFIG_HTC_I2CPLD)	+= htc-i2cpld.o

drivers/mfd/gateworks-gsc.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * The Gateworks System Controller (GSC) is a multi-function
+ * device designed for use in Gateworks Single Board Computers.
+ * The control interface is I2C, with an interrupt. The device supports
+ * system functions such as push-button monitoring, multiple ADC's for
+ * voltage and temperature monitoring, fan controller and watchdog monitor.
+ *
+ * Copyright (C) 2020 Gateworks Corporation
+ */
+
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/gsc.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <asm/unaligned.h>
+
+/*
+ * The GSC suffers from an errata where occasionally during
+ * ADC cycles the chip can NAK I2C transactions. To ensure we have reliable
+ * register access we place retries around register access.
+ */
+#define I2C_RETRIES	3
+
+int gsc_write(void *context, unsigned int reg, unsigned int val)
+{
+	struct i2c_client *client = context;
+	int retry, ret;
+
+	for (retry = 0; retry < I2C_RETRIES; retry++) {
+		ret = i2c_smbus_write_byte_data(client, reg, val);
+		/*
+		 * -EAGAIN returned when the i2c host controller is busy
+		 * -EIO returned when i2c device is busy
+		 */
+		if (ret != -EAGAIN && ret != -EIO)
+			break;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gsc_write);
+
+int gsc_read(void *context, unsigned int reg, unsigned int *val)
+{
+	struct i2c_client *client = context;
+	int retry, ret;
+
+	for (retry = 0; retry < I2C_RETRIES; retry++) {
+		ret = i2c_smbus_read_byte_data(client, reg);
+		/*
+		 * -EAGAIN returned when the i2c host controller is busy
+		 * -EIO returned when i2c device is busy
+		 */
+		if (ret != -EAGAIN && ret != -EIO)
+			break;
+	}
+	*val = ret & 0xff;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gsc_read);
+
+/*
+ * gsc_powerdown - API to use GSC to power down board for a specific time
+ *
+ * secs - number of seconds to remain powered off
+ */
+static int gsc_powerdown(struct gsc_dev *gsc, unsigned long secs)
+{
+	int ret;
+	unsigned char regs[4];
+
+	dev_info(&gsc->i2c->dev, "GSC powerdown for %ld seconds\n",
+		 secs);
+
+	put_unaligned_le32(secs, regs);
+	ret = regmap_bulk_write(gsc->regmap, GSC_TIME_ADD, regs, 4);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
+				 BIT(GSC_CTRL_1_SLEEP_ADD),
+				 BIT(GSC_CTRL_1_SLEEP_ADD));
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
+				 BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
+				 BIT(GSC_CTRL_1_SLEEP_ENABLE),
+				 BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
+				 BIT(GSC_CTRL_1_SLEEP_ENABLE));
+
+
+	return ret;
+}
+
+static ssize_t gsc_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct gsc_dev *gsc = dev_get_drvdata(dev);
+	const char *name = attr->attr.name;
+	int rz = 0;
+
+	if (strcasecmp(name, "fw_version") == 0)
+		rz = sprintf(buf, "%d\n", gsc->fwver);
+	else if (strcasecmp(name, "fw_crc") == 0)
+		rz = sprintf(buf, "0x%04x\n", gsc->fwcrc);
+	else
+		dev_err(dev, "invalid command: '%s'\n", name);
+
+	return rz;
+}
+
+static ssize_t gsc_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	struct gsc_dev *gsc = dev_get_drvdata(dev);
+	const char *name = attr->attr.name;
+	long value;
+
+	if (strcasecmp(name, "powerdown") == 0) {
+		if (kstrtol(buf, 0, &value) == 0)
+			gsc_powerdown(gsc, value);
+	} else {
+		dev_err(dev, "invalid command: '%s\n", name);
+	}
+
+	return count;
+}
+
+static struct device_attribute attr_fwver =
+	__ATTR(fw_version, 0440, gsc_show, NULL);
+static struct device_attribute attr_fwcrc =
+	__ATTR(fw_crc, 0440, gsc_show, NULL);
+static struct device_attribute attr_pwrdown =
+	__ATTR(powerdown, 0220, NULL, gsc_store);
+
+static struct attribute *gsc_attrs[] = {
+	&attr_fwver.attr,
+	&attr_fwcrc.attr,
+	&attr_pwrdown.attr,
+	NULL,
+};
+
+static struct attribute_group attr_group = {
+	.attrs = gsc_attrs,
+};
+
+static const struct of_device_id gsc_of_match[] = {
+	{ .compatible = "gw,gsc", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, gsc_of_match);
+
+static struct regmap_bus gsc_regmap_bus = {
+	.reg_read = gsc_read,
+	.reg_write = gsc_write,
+};
+
+static const struct regmap_config gsc_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_NONE,
+	.max_register = GSC_WP,
+};
+
+static const struct regmap_irq gsc_irqs[] = {
+	REGMAP_IRQ_REG(GSC_IRQ_PB, 0, BIT(GSC_IRQ_PB)),
+	REGMAP_IRQ_REG(GSC_IRQ_KEY_ERASED, 0, BIT(GSC_IRQ_KEY_ERASED)),
+	REGMAP_IRQ_REG(GSC_IRQ_EEPROM_WP, 0, BIT(GSC_IRQ_EEPROM_WP)),
+	REGMAP_IRQ_REG(GSC_IRQ_RESV, 0, BIT(GSC_IRQ_RESV)),
+	REGMAP_IRQ_REG(GSC_IRQ_GPIO, 0, BIT(GSC_IRQ_GPIO)),
+	REGMAP_IRQ_REG(GSC_IRQ_TAMPER, 0, BIT(GSC_IRQ_TAMPER)),
+	REGMAP_IRQ_REG(GSC_IRQ_WDT_TIMEOUT, 0, BIT(GSC_IRQ_WDT_TIMEOUT)),
+	REGMAP_IRQ_REG(GSC_IRQ_SWITCH_HOLD, 0, BIT(GSC_IRQ_SWITCH_HOLD)),
+};
+
+static const struct regmap_irq_chip gsc_irq_chip = {
+	.name = "gateworks-gsc",
+	.irqs = gsc_irqs,
+	.num_irqs = ARRAY_SIZE(gsc_irqs),
+	.num_regs = 1,
+	.status_base = GSC_IRQ_STATUS,
+	.mask_base = GSC_IRQ_ENABLE,
+	.mask_invert = true,
+	.ack_base = GSC_IRQ_STATUS,
+	.ack_invert = true,
+};
+
+static int gsc_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct gsc_dev *gsc;
+	struct regmap_irq_chip_data *irq_data;
+	int ret;
+	unsigned int reg;
+
+	gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
+	if (!gsc)
+		return -ENOMEM;
+
+	gsc->dev = &client->dev;
+	gsc->i2c = client;
+	i2c_set_clientdata(client, gsc);
+
+	gsc->regmap = devm_regmap_init(dev, &gsc_regmap_bus, client,
+				       &gsc_regmap_config);
+	if (IS_ERR(gsc->regmap))
+		return PTR_ERR(gsc->regmap);
+
+	if (regmap_read(gsc->regmap, GSC_FW_VER, &reg))
+		return -EIO;
+	gsc->fwver = reg;
+
+	regmap_read(gsc->regmap, GSC_FW_CRC, &reg);
+	gsc->fwcrc = reg;
+	regmap_read(gsc->regmap, GSC_FW_CRC + 1, &reg);
+	gsc->fwcrc |= reg << 8;
+
+	gsc->i2c_hwmon = devm_i2c_new_dummy_device(dev, client->adapter,
+						   GSC_HWMON);
+	if (IS_ERR(gsc->i2c_hwmon)) {
+		dev_err(dev, "Failed to allocate I2C device for HWMON\n");
+		return PTR_ERR(gsc->i2c_hwmon);
+	}
+
+	ret = devm_regmap_add_irq_chip(dev, gsc->regmap, client->irq,
+				       IRQF_ONESHOT | IRQF_SHARED |
+				       IRQF_TRIGGER_FALLING, 0,
+				       &gsc_irq_chip, &irq_data);
+	if (ret)
+		return ret;
+
+	dev_info(dev, "Gateworks System Controller v%d: fw 0x%04x\n",
+		 gsc->fwver, gsc->fwcrc);
+
+	ret = sysfs_create_group(&dev->kobj, &attr_group);
+	if (ret)
+		dev_err(dev, "failed to create sysfs attrs\n");
+
+	ret = devm_of_platform_populate(dev);
+	if (ret) {
+		sysfs_remove_group(&dev->kobj, &attr_group);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gsc_remove(struct i2c_client *client)
+{
+	sysfs_remove_group(&client->dev.kobj, &attr_group);
+
+	return 0;
+}
+
+static struct i2c_driver gsc_driver = {
+	.driver = {
+		.name	= "gateworks-gsc",
+		.of_match_table = gsc_of_match,
+	},
+	.probe_new	= gsc_probe,
+	.remove		= gsc_remove,
+};
+module_i2c_driver(gsc_driver);
+
+MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
+MODULE_DESCRIPTION("I2C Core interface for GSC");
+MODULE_LICENSE("GPL v2");

include/linux/mfd/gsc.h

+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2020 Gateworks Corporation
+ */
+#ifndef __LINUX_MFD_GSC_H_
+#define __LINUX_MFD_GSC_H_
+
+#include <linux/regmap.h>
+
+/* Device Addresses */
+#define GSC_MISC	0x20
+#define GSC_UPDATE	0x21
+#define GSC_GPIO	0x23
+#define GSC_HWMON	0x29
+#define GSC_EEPROM0	0x50
+#define GSC_EEPROM1	0x51
+#define GSC_EEPROM2	0x52
+#define GSC_EEPROM3	0x53
+#define GSC_RTC		0x68
+
+/* Register offsets */
+enum {
+	GSC_CTRL_0	= 0x00,
+	GSC_CTRL_1	= 0x01,
+	GSC_TIME	= 0x02,
+	GSC_TIME_ADD	= 0x06,
+	GSC_IRQ_STATUS	= 0x0A,
+	GSC_IRQ_ENABLE	= 0x0B,
+	GSC_FW_CRC	= 0x0C,
+	GSC_FW_VER	= 0x0E,
+	GSC_WP		= 0x0F,
+};
+
+/* Bit definitions */
+#define GSC_CTRL_0_PB_HARD_RESET	0
+#define GSC_CTRL_0_PB_CLEAR_SECURE_KEY	1
+#define GSC_CTRL_0_PB_SOFT_POWER_DOWN	2
+#define GSC_CTRL_0_PB_BOOT_ALTERNATE	3
+#define GSC_CTRL_0_PERFORM_CRC		4
+#define GSC_CTRL_0_TAMPER_DETECT	5
+#define GSC_CTRL_0_SWITCH_HOLD		6
+
+#define GSC_CTRL_1_SLEEP_ENABLE		0
+#define GSC_CTRL_1_SLEEP_ACTIVATE	1
+#define GSC_CTRL_1_SLEEP_ADD		2
+#define GSC_CTRL_1_SLEEP_NOWAKEPB	3
+#define GSC_CTRL_1_WDT_TIME		4
+#define GSC_CTRL_1_WDT_ENABLE		5
+#define GSC_CTRL_1_SWITCH_BOOT_ENABLE	6
+#define GSC_CTRL_1_SWITCH_BOOT_CLEAR	7
+
+#define GSC_IRQ_PB			0
+#define GSC_IRQ_KEY_ERASED		1
+#define GSC_IRQ_EEPROM_WP		2
+#define GSC_IRQ_RESV			3
+#define GSC_IRQ_GPIO			4
+#define GSC_IRQ_TAMPER			5
+#define GSC_IRQ_WDT_TIMEOUT		6
+#define GSC_IRQ_SWITCH_HOLD		7
+
+int gsc_read(void *context, unsigned int reg, unsigned int *val);
+int gsc_write(void *context, unsigned int reg, unsigned int val);
+
+struct gsc_dev {
+	struct device *dev;
+
+	struct i2c_client *i2c;		/* 0x20: interrupt controller, WDT */
+	struct i2c_client *i2c_hwmon;	/* 0x29: hwmon, fan controller */
+
+	struct regmap *regmap;
+
+	unsigned int fwver;
+	unsigned short fwcrc;
+};
+
+#endif /* __LINUX_MFD_GSC_H_ */

include/linux/platform_data/gsc_hwmon.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _GSC_HWMON_H
+#define _GSC_HWMON_H
+
+enum gsc_hwmon_mode {
+	mode_temperature,
+	mode_voltage,
+	mode_voltage_raw,
+	mode_max,
+};
+
+/**
+ * struct gsc_hwmon_channel - configuration parameters
+ * @reg:  I2C register offset
+ * @mode: channel mode
+ * @name: channel name
+ * @mvoffset: voltage offset
+ * @vdiv: voltage divider array (2 resistor values in milli-ohms)
+ */
+struct gsc_hwmon_channel {
+	unsigned int reg;
+	unsigned int mode;
+	const char *name;
+	unsigned int mvoffset;
+	unsigned int vdiv[2];
+};
+
+/**
+ * struct gsc_hwmon_platform_data - platform data for gsc_hwmon driver
+ * @channels:	pointer to array of gsc_hwmon_channel structures
+ *		describing channels
+ * @nchannels:	number of elements in @channels array
+ * @vreference: voltage reference (mV)
+ * @resolution: ADC bit resolution
+ * @fan_base: register base for FAN controller
+ */
+struct gsc_hwmon_platform_data {
+	const struct gsc_hwmon_channel *channels;
+	int nchannels;
+	unsigned int resolution;
+	unsigned int vreference;
+	unsigned int fan_base;
+};
+#endif