hwmon: introduce hwmon_sanitize_name()

More and more drivers will check for bad characters in the hwmon name
and all are using the same code snippet. Consolidate that code by adding
a new hwmon_sanitize_name() function.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20220405092452.4033674-2-michael@walle.cc
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/hwmon-kernel-api.rst

@@ -50,6 +50,10 @@ register/unregister functions::
 
   void devm_hwmon_device_unregister(struct device *dev);
 
+  char *hwmon_sanitize_name(const char *name);
+
+  char *devm_hwmon_sanitize_name(struct device *dev, const char *name);
+
 hwmon_device_register_with_groups registers a hardware monitoring device.
 The first parameter of this function is a pointer to the parent device.
 The name parameter is a pointer to the hwmon device name. The registration
@@ -95,6 +99,18 @@ All supported hwmon device registration functions only accept valid device
 names. Device names including invalid characters (whitespace, '*', or '-')
 will be rejected. The 'name' parameter is mandatory.
 
+If the driver doesn't use a static device name (for example it uses
+dev_name()), and therefore cannot make sure the name only contains valid
+characters, hwmon_sanitize_name can be used. This convenience function
+will duplicate the string and replace any invalid characters with an
+underscore. It will allocate memory for the new string and it is the
+responsibility of the caller to release the memory when the device is
+removed.
+
+devm_hwmon_sanitize_name is the resource managed version of
+hwmon_sanitize_name; the memory will be freed automatically on device
+removal.
+
 Using devm_hwmon_device_register_with_info()
 --------------------------------------------
 

drivers/hwmon/hwmon.c

@@ -1057,6 +1057,59 @@ void devm_hwmon_device_unregister(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(devm_hwmon_device_unregister);
 
+static char *__hwmon_sanitize_name(struct device *dev, const char *old_name)
+{
+	char *name, *p;
+
+	if (dev)
+		name = devm_kstrdup(dev, old_name, GFP_KERNEL);
+	else
+		name = kstrdup(old_name, GFP_KERNEL);
+	if (!name)
+		return ERR_PTR(-ENOMEM);
+
+	for (p = name; *p; p++)
+		if (hwmon_is_bad_char(*p))
+			*p = '_';
+
+	return name;
+}
+
+/**
+ * hwmon_sanitize_name - Replaces invalid characters in a hwmon name
+ * @name: NUL-terminated name
+ *
+ * Allocates a new string where any invalid characters will be replaced
+ * by an underscore. It is the responsibility of the caller to release
+ * the memory.
+ *
+ * Returns newly allocated name, or ERR_PTR on error.
+ */
+char *hwmon_sanitize_name(const char *name)
+{
+	return __hwmon_sanitize_name(NULL, name);
+}
+EXPORT_SYMBOL_GPL(hwmon_sanitize_name);
+
+/**
+ * devm_hwmon_sanitize_name - resource managed hwmon_sanitize_name()
+ * @dev: device to allocate memory for
+ * @name: NUL-terminated name
+ *
+ * Allocates a new string where any invalid characters will be replaced
+ * by an underscore.
+ *
+ * Returns newly allocated name, or ERR_PTR on error.
+ */
+char *devm_hwmon_sanitize_name(struct device *dev, const char *name)
+{
+	if (!dev)
+		return ERR_PTR(-EINVAL);
+
+	return __hwmon_sanitize_name(dev, name);
+}
+EXPORT_SYMBOL_GPL(devm_hwmon_sanitize_name);
+
 static void __init hwmon_pci_quirks(void)
 {
 #if defined CONFIG_X86 && defined CONFIG_PCI

include/linux/hwmon.h

@@ -461,6 +461,9 @@ void devm_hwmon_device_unregister(struct device *dev);
 int hwmon_notify_event(struct device *dev, enum hwmon_sensor_types type,
 		       u32 attr, int channel);
 
+char *hwmon_sanitize_name(const char *name);
+char *devm_hwmon_sanitize_name(struct device *dev, const char *name);
+
 /**
  * hwmon_is_bad_char - Is the char invalid in a hwmon name
  * @ch: the char to be considered