hwmon: (core) New hwmon registration API

Up to now, each hwmon driver has to implement its own sysfs attributes.
This requires a lot of template code, and distracts from the driver's core
function to read and write chip registers.

To be able to reduce driver complexity, move sensor attribute handling
and thermal zone registration into hwmon core. By using the new API,
driver code and data size is typically reduced by 20-70%, depending
on driver complexity and the number of sysfs attributes supported.

With this patch, the new API only supports thermal sensors. Support for
other sensor types will be added with subsequent patches.

Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/hwmon.c

@@ -12,6 +12,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/bitops.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/gfp.h>
@@ -21,6 +22,7 @@
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/thermal.h>
 
 #define HWMON_ID_PREFIX "hwmon"
 #define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"
@@ -28,9 +30,35 @@
 struct hwmon_device {
 	const char *name;
 	struct device dev;
+	const struct hwmon_chip_info *chip;
+
+	struct attribute_group group;
+	const struct attribute_group **groups;
 };
+
 #define to_hwmon_device(d) container_of(d, struct hwmon_device, dev)
 
+struct hwmon_device_attribute {
+	struct device_attribute dev_attr;
+	const struct hwmon_ops *ops;
+	enum hwmon_sensor_types type;
+	u32 attr;
+	int index;
+};
+
+#define to_hwmon_attr(d) \
+	container_of(d, struct hwmon_device_attribute, dev_attr)
+
+/*
+ * Thermal zone information
+ * In addition to the reference to the hwmon device,
+ * also provides the sensor index.
+ */
+struct hwmon_thermal_data {
+	struct hwmon_device *hwdev;	/* Reference to hwmon device */
+	int index;			/* sensor index */
+};
+
 static ssize_t
 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 {
@@ -78,6 +106,375 @@ static struct class hwmon_class = {
 
 static DEFINE_IDA(hwmon_ida);
 
+/* Thermal zone handling */
+
+#if IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF)
+static int hwmon_thermal_get_temp(void *data, int *temp)
+{
+	struct hwmon_thermal_data *tdata = data;
+	struct hwmon_device *hwdev = tdata->hwdev;
+	int ret;
+	long t;
+
+	ret = hwdev->chip->ops->read(&hwdev->dev, hwmon_temp, hwmon_temp_input,
+				     tdata->index, &t);
+	if (ret < 0)
+		return ret;
+
+	*temp = t;
+
+	return 0;
+}
+
+static struct thermal_zone_of_device_ops hwmon_thermal_ops = {
+	.get_temp = hwmon_thermal_get_temp,
+};
+
+static int hwmon_thermal_add_sensor(struct device *dev,
+				    struct hwmon_device *hwdev, int index)
+{
+	struct hwmon_thermal_data *tdata;
+
+	tdata = devm_kzalloc(dev, sizeof(*tdata), GFP_KERNEL);
+	if (!tdata)
+		return -ENOMEM;
+
+	tdata->hwdev = hwdev;
+	tdata->index = index;
+
+	devm_thermal_zone_of_sensor_register(&hwdev->dev, index, tdata,
+					     &hwmon_thermal_ops);
+
+	return 0;
+}
+#else
+static int hwmon_thermal_add_sensor(struct device *dev,
+				    struct hwmon_device *hwdev, int index)
+{
+	return 0;
+}
+#endif /* IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF) */
+
+/* sysfs attribute management */
+
+static ssize_t hwmon_attr_show(struct device *dev,
+			       struct device_attribute *devattr, char *buf)
+{
+	struct hwmon_device_attribute *hattr = to_hwmon_attr(devattr);
+	long val;
+	int ret;
+
+	ret = hattr->ops->read(dev, hattr->type, hattr->attr, hattr->index,
+			       &val);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%ld\n", val);
+}
+
+static ssize_t hwmon_attr_store(struct device *dev,
+				struct device_attribute *devattr,
+				const char *buf, size_t count)
+{
+	struct hwmon_device_attribute *hattr = to_hwmon_attr(devattr);
+	long val;
+	int ret;
+
+	ret = kstrtol(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	ret = hattr->ops->write(dev, hattr->type, hattr->attr, hattr->index,
+				val);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static int hwmon_attr_base(enum hwmon_sensor_types type)
+{
+	if (type == hwmon_in)
+		return 0;
+	return 1;
+}
+
+static struct attribute *hwmon_genattr(struct device *dev,
+				       const void *drvdata,
+				       enum hwmon_sensor_types type,
+				       u32 attr,
+				       int index,
+				       const char *template,
+				       const struct hwmon_ops *ops)
+{
+	struct hwmon_device_attribute *hattr;
+	struct device_attribute *dattr;
+	struct attribute *a;
+	umode_t mode;
+	char *name;
+
+	/* The attribute is invisible if there is no template string */
+	if (!template)
+		return ERR_PTR(-ENOENT);
+
+	mode = ops->is_visible(drvdata, type, attr, index);
+	if (!mode)
+		return ERR_PTR(-ENOENT);
+
+	if ((mode & S_IRUGO) && !ops->read)
+		return ERR_PTR(-EINVAL);
+	if ((mode & S_IWUGO) && !ops->write)
+		return ERR_PTR(-EINVAL);
+
+	if (type == hwmon_chip) {
+		name = (char *)template;
+	} else {
+		name = devm_kzalloc(dev, strlen(template) + 16, GFP_KERNEL);
+		if (!name)
+			return ERR_PTR(-ENOMEM);
+		scnprintf(name, strlen(template) + 16, template,
+			  index + hwmon_attr_base(type));
+	}
+
+	hattr = devm_kzalloc(dev, sizeof(*hattr), GFP_KERNEL);
+	if (!hattr)
+		return ERR_PTR(-ENOMEM);
+
+	hattr->type = type;
+	hattr->attr = attr;
+	hattr->index = index;
+	hattr->ops = ops;
+
+	dattr = &hattr->dev_attr;
+	dattr->show = hwmon_attr_show;
+	dattr->store = hwmon_attr_store;
+
+	a = &dattr->attr;
+	sysfs_attr_init(a);
+	a->name = name;
+	a->mode = mode;
+
+	return a;
+}
+
+static const char * const hwmon_chip_attr_templates[] = {
+	[hwmon_chip_temp_reset_history] = "temp_reset_history",
+	[hwmon_chip_update_interval] = "update_interval",
+	[hwmon_chip_alarms] = "alarms",
+};
+
+static const char * const hwmon_temp_attr_templates[] = {
+	[hwmon_temp_input] = "temp%d_input",
+	[hwmon_temp_type] = "temp%d_type",
+	[hwmon_temp_lcrit] = "temp%d_lcrit",
+	[hwmon_temp_lcrit_hyst] = "temp%d_lcrit_hyst",
+	[hwmon_temp_min] = "temp%d_min",
+	[hwmon_temp_min_hyst] = "temp%d_min_hyst",
+	[hwmon_temp_max] = "temp%d_max",
+	[hwmon_temp_max_hyst] = "temp%d_max_hyst",
+	[hwmon_temp_crit] = "temp%d_crit",
+	[hwmon_temp_crit_hyst] = "temp%d_crit_hyst",
+	[hwmon_temp_emergency] = "temp%d_emergency",
+	[hwmon_temp_emergency_hyst] = "temp%d_emergency_hyst",
+	[hwmon_temp_alarm] = "temp%d_alarm",
+	[hwmon_temp_lcrit_alarm] = "temp%d_lcrit_alarm",
+	[hwmon_temp_min_alarm] = "temp%d_min_alarm",
+	[hwmon_temp_max_alarm] = "temp%d_max_alarm",
+	[hwmon_temp_crit_alarm] = "temp%d_crit_alarm",
+	[hwmon_temp_emergency_alarm] = "temp%d_emergency_alarm",
+	[hwmon_temp_fault] = "temp%d_fault",
+	[hwmon_temp_offset] = "temp%d_offset",
+	[hwmon_temp_label] = "temp%d_label",
+	[hwmon_temp_lowest] = "temp%d_lowest",
+	[hwmon_temp_highest] = "temp%d_highest",
+	[hwmon_temp_reset_history] = "temp%d_reset_history",
+};
+
+static const char * const *__templates[] = {
+	[hwmon_chip] = hwmon_chip_attr_templates,
+	[hwmon_temp] = hwmon_temp_attr_templates,
+};
+
+static const int __templates_size[] = {
+	[hwmon_chip] = ARRAY_SIZE(hwmon_chip_attr_templates),
+	[hwmon_temp] = ARRAY_SIZE(hwmon_temp_attr_templates),
+};
+
+static int hwmon_num_channel_attrs(const struct hwmon_channel_info *info)
+{
+	int i, n;
+
+	for (i = n = 0; info->config[i]; i++)
+		n += hweight32(info->config[i]);
+
+	return n;
+}
+
+static int hwmon_genattrs(struct device *dev,
+			  const void *drvdata,
+			  struct attribute **attrs,
+			  const struct hwmon_ops *ops,
+			  const struct hwmon_channel_info *info)
+{
+	const char * const *templates;
+	int template_size;
+	int i, aindex = 0;
+
+	if (info->type >= ARRAY_SIZE(__templates))
+		return -EINVAL;
+
+	templates = __templates[info->type];
+	template_size = __templates_size[info->type];
+
+	for (i = 0; info->config[i]; i++) {
+		u32 attr_mask = info->config[i];
+		u32 attr;
+
+		while (attr_mask) {
+			struct attribute *a;
+
+			attr = __ffs(attr_mask);
+			attr_mask &= ~BIT(attr);
+			if (attr >= template_size)
+				return -EINVAL;
+			a = hwmon_genattr(dev, drvdata, info->type, attr, i,
+					  templates[attr], ops);
+			if (IS_ERR(a)) {
+				if (PTR_ERR(a) != -ENOENT)
+					return PTR_ERR(a);
+				continue;
+			}
+			attrs[aindex++] = a;
+		}
+	}
+	return aindex;
+}
+
+static struct attribute **
+__hwmon_create_attrs(struct device *dev, const void *drvdata,
+		     const struct hwmon_chip_info *chip)
+{
+	int ret, i, aindex = 0, nattrs = 0;
+	struct attribute **attrs;
+
+	for (i = 0; chip->info[i]; i++)
+		nattrs += hwmon_num_channel_attrs(chip->info[i]);
+
+	if (nattrs == 0)
+		return ERR_PTR(-EINVAL);
+
+	attrs = devm_kcalloc(dev, nattrs + 1, sizeof(*attrs), GFP_KERNEL);
+	if (!attrs)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; chip->info[i]; i++) {
+		ret = hwmon_genattrs(dev, drvdata, &attrs[aindex], chip->ops,
+				     chip->info[i]);
+		if (ret < 0)
+			return ERR_PTR(ret);
+		aindex += ret;
+	}
+
+	return attrs;
+}
+
+static struct device *
+__hwmon_device_register(struct device *dev, const char *name, void *drvdata,
+			const struct hwmon_chip_info *chip,
+			const struct attribute_group **groups)
+{
+	struct hwmon_device *hwdev;
+	struct device *hdev;
+	int i, j, err, id;
+
+	/* Do not accept invalid characters in hwmon name attribute */
+	if (name && (!strlen(name) || strpbrk(name, "-* \t\n")))
+		return ERR_PTR(-EINVAL);
+
+	id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
+	if (id < 0)
+		return ERR_PTR(id);
+
+	hwdev = kzalloc(sizeof(*hwdev), GFP_KERNEL);
+	if (hwdev == NULL) {
+		err = -ENOMEM;
+		goto ida_remove;
+	}
+
+	hdev = &hwdev->dev;
+
+	if (chip && chip->ops->is_visible) {
+		struct attribute **attrs;
+		int ngroups = 2;
+
+		if (groups)
+			for (i = 0; groups[i]; i++)
+				ngroups++;
+
+		hwdev->groups = devm_kcalloc(dev, ngroups, sizeof(*groups),
+					     GFP_KERNEL);
+		if (!hwdev->groups)
+			return ERR_PTR(-ENOMEM);
+
+		attrs = __hwmon_create_attrs(dev, drvdata, chip);
+		if (IS_ERR(attrs)) {
+			err = PTR_ERR(attrs);
+			goto free_hwmon;
+		}
+
+		hwdev->group.attrs = attrs;
+		ngroups = 0;
+		hwdev->groups[ngroups++] = &hwdev->group;
+
+		if (groups) {
+			for (i = 0; groups[i]; i++)
+				hwdev->groups[ngroups++] = groups[i];
+		}
+
+		hdev->groups = hwdev->groups;
+	} else {
+		hdev->groups = groups;
+	}
+
+	hwdev->name = name;
+	hdev->class = &hwmon_class;
+	hdev->parent = dev;
+	hdev->of_node = dev ? dev->of_node : NULL;
+	hwdev->chip = chip;
+	dev_set_drvdata(hdev, drvdata);
+	dev_set_name(hdev, HWMON_ID_FORMAT, id);
+	err = device_register(hdev);
+	if (err)
+		goto free_hwmon;
+
+	if (chip && chip->ops->is_visible && chip->ops->read &&
+	    chip->info[0]->type == hwmon_chip &&
+	    (chip->info[0]->config[0] & HWMON_C_REGISTER_TZ)) {
+		const struct hwmon_channel_info **info = chip->info;
+
+		for (i = 1; info[i]; i++) {
+			if (info[i]->type != hwmon_temp)
+				continue;
+
+			for (j = 0; info[i]->config[j]; j++) {
+				if (!chip->ops->is_visible(drvdata, hwmon_temp,
+							   hwmon_temp_input, j))
+					continue;
+				if (info[i]->config[j] & HWMON_T_INPUT)
+					hwmon_thermal_add_sensor(dev, hwdev, j);
+			}
+		}
+	}
+
+	return hdev;
+
+free_hwmon:
+	kfree(hwdev);
+ida_remove:
+	ida_simple_remove(&hwmon_ida, id);
+	return ERR_PTR(err);
+}
+
 /**
  * hwmon_device_register_with_groups - register w/ hwmon
  * @dev: the parent device
@@ -95,44 +492,36 @@ hwmon_device_register_with_groups(struct device *dev, const char *name,
 				  void *drvdata,
 				  const struct attribute_group **groups)
 {
-	struct hwmon_device *hwdev;
-	int err, id;
-
-	/* Do not accept invalid characters in hwmon name attribute */
-	if (name && (!strlen(name) || strpbrk(name, "-* \t\n")))
-		return ERR_PTR(-EINVAL);
-
-	id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
-	if (id < 0)
-		return ERR_PTR(id);
-
-	hwdev = kzalloc(sizeof(*hwdev), GFP_KERNEL);
-	if (hwdev == NULL) {
-		err = -ENOMEM;
-		goto ida_remove;
-	}
-
-	hwdev->name = name;
-	hwdev->dev.class = &hwmon_class;
-	hwdev->dev.parent = dev;
-	hwdev->dev.groups = groups;
-	hwdev->dev.of_node = dev ? dev->of_node : NULL;
-	dev_set_drvdata(&hwdev->dev, drvdata);
-	dev_set_name(&hwdev->dev, HWMON_ID_FORMAT, id);
-	err = device_register(&hwdev->dev);
-	if (err)
-		goto free;
-
-	return &hwdev->dev;
-
-free:
-	kfree(hwdev);
-ida_remove:
-	ida_simple_remove(&hwmon_ida, id);
-	return ERR_PTR(err);
+	return __hwmon_device_register(dev, name, drvdata, NULL, groups);
 }
 EXPORT_SYMBOL_GPL(hwmon_device_register_with_groups);
 
+/**
+ * hwmon_device_register_with_info - register w/ hwmon
+ * @dev: the parent device
+ * @name: hwmon name attribute
+ * @drvdata: driver data to attach to created device
+ * @info: Pointer to hwmon chip information
+ * @groups - pointer to list of driver specific attribute groups
+ *
+ * hwmon_device_unregister() must be called when the device is no
+ * longer needed.
+ *
+ * Returns the pointer to the new device.
+ */
+struct device *
+hwmon_device_register_with_info(struct device *dev, const char *name,
+				void *drvdata,
+				const struct hwmon_chip_info *chip,
+				const struct attribute_group **groups)
+{
+	if (chip && (!chip->ops || !chip->info))
+		return ERR_PTR(-EINVAL);
+
+	return __hwmon_device_register(dev, name, drvdata, chip, groups);
+}
+EXPORT_SYMBOL_GPL(hwmon_device_register_with_info);
+
 /**
  * hwmon_device_register - register w/ hwmon
  * @dev: the device to register
@@ -211,6 +600,48 @@ devm_hwmon_device_register_with_groups(struct device *dev, const char *name,
 }
 EXPORT_SYMBOL_GPL(devm_hwmon_device_register_with_groups);
 
+/**
+ * devm_hwmon_device_register_with_info - register w/ hwmon
+ * @dev: the parent device
+ * @name: hwmon name attribute
+ * @drvdata: driver data to attach to created device
+ * @info: Pointer to hwmon chip information
+ * @groups - pointer to list of driver specific attribute groups
+ *
+ * Returns the pointer to the new device. The new device is automatically
+ * unregistered with the parent device.
+ */
+struct device *
+devm_hwmon_device_register_with_info(struct device *dev, const char *name,
+				     void *drvdata,
+				     const struct hwmon_chip_info *chip,
+				     const struct attribute_group **groups)
+{
+	struct device **ptr, *hwdev;
+
+	if (!dev)
+		return ERR_PTR(-EINVAL);
+
+	ptr = devres_alloc(devm_hwmon_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	hwdev = hwmon_device_register_with_info(dev, name, drvdata, chip,
+						groups);
+	if (IS_ERR(hwdev))
+		goto error;
+
+	*ptr = hwdev;
+	devres_add(dev, ptr);
+
+	return hwdev;
+
+error:
+	devres_free(ptr);
+	return hwdev;
+}
+EXPORT_SYMBOL_GPL(devm_hwmon_device_register_with_info);
+
 static int devm_hwmon_match(struct device *dev, void *res, void *data)
 {
 	struct device **hwdev = res;

include/linux/hwmon.h

@@ -14,9 +14,147 @@
 #ifndef _HWMON_H_
 #define _HWMON_H_
 
+#include <linux/bitops.h>
+
 struct device;
 struct attribute_group;
 
+enum hwmon_sensor_types {
+	hwmon_chip,
+	hwmon_temp,
+	hwmon_in,
+	hwmon_curr,
+	hwmon_power,
+	hwmon_energy,
+};
+
+enum hwmon_chip_attributes {
+	hwmon_chip_temp_reset_history,
+	hwmon_chip_register_tz,
+	hwmon_chip_update_interval,
+	hwmon_chip_alarms,
+};
+
+#define HWMON_C_TEMP_RESET_HISTORY	BIT(hwmon_chip_temp_reset_history)
+#define HWMON_C_IN_RESET_HISTORY	BIT(hwmon_chip_in_reset_history)
+#define HWMON_C_REGISTER_TZ		BIT(hwmon_chip_register_tz)
+#define HWMON_C_UPDATE_INTERVAL		BIT(hwmon_chip_update_interval)
+#define HWMON_C_ALARMS			BIT(hwmon_chip_alarms)
+
+enum hwmon_temp_attributes {
+	hwmon_temp_input = 0,
+	hwmon_temp_type,
+	hwmon_temp_lcrit,
+	hwmon_temp_lcrit_hyst,
+	hwmon_temp_min,
+	hwmon_temp_min_hyst,
+	hwmon_temp_max,
+	hwmon_temp_max_hyst,
+	hwmon_temp_crit,
+	hwmon_temp_crit_hyst,
+	hwmon_temp_emergency,
+	hwmon_temp_emergency_hyst,
+	hwmon_temp_alarm,
+	hwmon_temp_lcrit_alarm,
+	hwmon_temp_min_alarm,
+	hwmon_temp_max_alarm,
+	hwmon_temp_crit_alarm,
+	hwmon_temp_emergency_alarm,
+	hwmon_temp_fault,
+	hwmon_temp_offset,
+	hwmon_temp_label,
+	hwmon_temp_lowest,
+	hwmon_temp_highest,
+	hwmon_temp_reset_history,
+};
+
+#define HWMON_T_INPUT		BIT(hwmon_temp_input)
+#define HWMON_T_TYPE		BIT(hwmon_temp_type)
+#define HWMON_T_LCRIT		BIT(hwmon_temp_lcrit)
+#define HWMON_T_LCRIT_HYST	BIT(hwmon_temp_lcrit_hyst)
+#define HWMON_T_MIN		BIT(hwmon_temp_min)
+#define HWMON_T_MIN_HYST	BIT(hwmon_temp_min_hyst)
+#define HWMON_T_MAX		BIT(hwmon_temp_max)
+#define HWMON_T_MAX_HYST	BIT(hwmon_temp_max_hyst)
+#define HWMON_T_CRIT		BIT(hwmon_temp_crit)
+#define HWMON_T_CRIT_HYST	BIT(hwmon_temp_crit_hyst)
+#define HWMON_T_EMERGENCY	BIT(hwmon_temp_emergency)
+#define HWMON_T_EMERGENCY_HYST	BIT(hwmon_temp_emergency_hyst)
+#define HWMON_T_MIN_ALARM	BIT(hwmon_temp_min_alarm)
+#define HWMON_T_MAX_ALARM	BIT(hwmon_temp_max_alarm)
+#define HWMON_T_CRIT_ALARM	BIT(hwmon_temp_crit_alarm)
+#define HWMON_T_EMERGENCY_ALARM	BIT(hwmon_temp_emergency_alarm)
+#define HWMON_T_FAULT		BIT(hwmon_temp_fault)
+#define HWMON_T_OFFSET		BIT(hwmon_temp_offset)
+#define HWMON_T_LABEL		BIT(hwmon_temp_label)
+#define HWMON_T_LOWEST		BIT(hwmon_temp_lowest)
+#define HWMON_T_HIGHEST		BIT(hwmon_temp_highest)
+#define HWMON_T_RESET_HISTORY	BIT(hwmon_temp_reset_history)
+
+/**
+ * struct hwmon_ops - hwmon device operations
+ * @is_visible: Callback to return attribute visibility. Mandatory.
+ *		Parameters are:
+ *		@const void *drvdata:
+ *			Pointer to driver-private data structure passed
+ *			as argument to hwmon_device_register_with_info().
+ *		@type:	Sensor type
+ *		@attr:	Sensor attribute
+ *		@channel:
+ *			Channel number
+ *		The function returns the file permissions.
+ *		If the return value is 0, no attribute will be created.
+ * @read:       Read callback. Optional. If not provided, attributes
+ *		will not be readable.
+ *		Parameters are:
+ *		@dev:	Pointer to hardware monitoring device
+ *		@type:	Sensor type
+ *		@attr:	Sensor attribute
+ *		@channel:
+ *			Channel number
+ *		@val:	Pointer to returned value
+ *		The function returns 0 on success or a negative error number.
+ * @write:	Write callback. Optional. If not provided, attributes
+ *		will not be writable.
+ *		Parameters are:
+ *		@dev:	Pointer to hardware monitoring device
+ *		@type:	Sensor type
+ *		@attr:	Sensor attribute
+ *		@channel:
+ *			Channel number
+ *		@val:	Value to write
+ *		The function returns 0 on success or a negative error number.
+ */
+struct hwmon_ops {
+	umode_t (*is_visible)(const void *drvdata, enum hwmon_sensor_types type,
+			      u32 attr, int channel);
+	int (*read)(struct device *dev, enum hwmon_sensor_types type,
+		    u32 attr, int channel, long *val);
+	int (*write)(struct device *dev, enum hwmon_sensor_types type,
+		     u32 attr, int channel, long val);
+};
+
+/**
+ * Channel information
+ * @type:	Channel type.
+ * @config:	Pointer to NULL-terminated list of channel parameters.
+ *		Use for per-channel attributes.
+ */
+struct hwmon_channel_info {
+	enum hwmon_sensor_types type;
+	const u32 *config;
+};
+
+/**
+ * Chip configuration
+ * @ops:	Pointer to hwmon operations.
+ * @info:	Null-terminated list of channel information.
+ */
+struct hwmon_chip_info {
+	const struct hwmon_ops *ops;
+	const struct hwmon_channel_info **info;
+};
+
 struct device *hwmon_device_register(struct device *dev);
 struct device *
 hwmon_device_register_with_groups(struct device *dev, const char *name,
@@ -26,6 +164,16 @@ struct device *
 devm_hwmon_device_register_with_groups(struct device *dev, const char *name,
 				       void *drvdata,
 				       const struct attribute_group **groups);
+struct device *
+hwmon_device_register_with_info(struct device *dev,
+				const char *name, void *drvdata,
+				const struct hwmon_chip_info *info,
+				const struct attribute_group **groups);
+struct device *
+devm_hwmon_device_register_with_info(struct device *dev,
+				     const char *name, void *drvdata,
+				     const struct hwmon_chip_info *info,
+				     const struct attribute_group **groups);
 
 void hwmon_device_unregister(struct device *dev);
 void devm_hwmon_device_unregister(struct device *dev);