[PATCH RFT 4/5] hwmon: Implement hwmon_update_groups()

[Guenter Roeck <linux@roeck-us.net>]

In some situations the visibility of hwmon sysfs attributes may change.
Support this by providing a new API function hwmon_update_groups()
to update both visible attributes and thermal zones.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 Documentation/hwmon/hwmon-kernel-api.rst |  8 ++++++++
 drivers/hwmon/hwmon.c                    | 24 ++++++++++++++++++++++++
 include/linux/hwmon.h                    |  2 ++
 3 files changed, 34 insertions(+)

diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst
index 1d7f1397a827..a41b1038fbf0 100644
--- a/Documentation/hwmon/hwmon-kernel-api.rst
+++ b/Documentation/hwmon/hwmon-kernel-api.rst
@@ -42,6 +42,8 @@ register/unregister functions::
 
   char *devm_hwmon_sanitize_name(struct device *dev, const char *name);
 
+  int hwmon_update_groups(struct device *dev);
+
   void hwmon_lock(struct device *dev);
   void hwmon_unlock(struct device *dev);
 
@@ -89,6 +91,12 @@ for other functions such as interrupt handlers or for attributes which are
 fully implemented in the driver, hwmon_lock() and hwmon_unlock() can be used
 to ensure that calls to those functions are serialized.
 
+If the visibility of sysfs attributes changes during runtime, the driver
+needs to call hwmon_update_groups() with the hwmon device as parameter
+to update attribute visibility. If the driver registered thermal zones
+using hwmon_device_register_with_info() and the visibility of thermal
+sensors changes, this call will also update thermal zones as needed.
+
 Using devm_hwmon_device_register_with_info()
 --------------------------------------------
 
diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index cb89218a0b6a..9163b8290dbe 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -330,6 +330,11 @@ static int hwmon_thermal_register_sensors(struct device *dev)
 	return hwmon_thermal_handle_sensors(dev, false);
 }
 
+static int hwmon_thermal_update_sensors(struct device *dev)
+{
+	return hwmon_thermal_handle_sensors(dev, true);
+}
+
 static void hwmon_thermal_notify(struct device *dev, int index)
 {
 	struct hwmon_thermal_data *tzdata = hwmon_thermal_find_tz(dev, index);
@@ -799,6 +804,25 @@ static const int __templates_size[] = {
 	[hwmon_intrusion] = ARRAY_SIZE(hwmon_intrusion_attr_templates),
 };
 
+int hwmon_update_groups(struct device *dev)
+{
+	struct hwmon_device *hwdev = to_hwmon_device(dev);
+	const struct hwmon_chip_info *chip = hwdev->chip;
+	const struct hwmon_channel_info * const *info;
+	int ret;
+
+	ret = sysfs_update_groups(&dev->kobj, dev->groups);
+	if (ret || !chip)
+		return ret;
+
+	info = chip->info;
+	if (info[0]->type != hwmon_chip || !(info[0]->config[0] & HWMON_C_REGISTER_TZ))
+		return 0;
+
+	return hwmon_thermal_update_sensors(dev);
+}
+EXPORT_SYMBOL_GPL(hwmon_update_groups);
+
 int hwmon_notify_event(struct device *dev, enum hwmon_sensor_types type,
 		       u32 attr, int channel)
 {
diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
index 301a83afbd66..8cadba24ed4b 100644
--- a/include/linux/hwmon.h
+++ b/include/linux/hwmon.h
@@ -492,6 +492,8 @@ int hwmon_notify_event(struct device *dev, enum hwmon_sensor_types type,
 char *hwmon_sanitize_name(const char *name);
 char *devm_hwmon_sanitize_name(struct device *dev, const char *name);
 
+int hwmon_update_groups(struct device *dev);
+
 void hwmon_lock(struct device *dev);
 void hwmon_unlock(struct device *dev);
 
-- 
2.45.2