hwmon: Introduce SENSOR_DEVICE_ATTR_{RO, RW, WO} and variants

Introduce SENSOR_DEVICE_ATTR_{RO,RW,WO} and SENSOR_DEVICE_ATTR_2_{RO,RW,WO}
as simplified variants of SENSOR_DEVICE_ATTR and SENSOR_DEVICE_ATTR_2 to
simplify the source code, improve readbility, and reduce the chance of
inconsistencies.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/hwmon-kernel-api.txt

@@ -299,17 +299,25 @@ functions is used.
 The header file linux/hwmon-sysfs.h provides a number of useful macros to
 declare and use hardware monitoring sysfs attributes.
 
-In many cases, you can use the exsting define DEVICE_ATTR to declare such
+In many cases, you can use the exsting define DEVICE_ATTR or its variants
-attributes. This is feasible if an attribute has no additional context. However,
+DEVICE_ATTR_{RW,RO,WO} to declare such attributes. This is feasible if an
-in many cases there will be additional information such as a sensor index which
+attribute has no additional context. However, in many cases there will be
-will need to be passed to the sysfs attribute handling function.
+additional information such as a sensor index which will need to be passed
+to the sysfs attribute handling function.
 
 SENSOR_DEVICE_ATTR and SENSOR_DEVICE_ATTR_2 can be used to define attributes
 which need such additional context information. SENSOR_DEVICE_ATTR requires
 one additional argument, SENSOR_DEVICE_ATTR_2 requires two.
 
-SENSOR_DEVICE_ATTR defines a struct sensor_device_attribute variable.
+Simplified variants of SENSOR_DEVICE_ATTR and SENSOR_DEVICE_ATTR_2 are available
-This structure has the following fields.
+and should be used if standard attribute permissions and function names are
+feasible. Standard permissions are 0644 for SENSOR_DEVICE_ATTR[_2]_RW,
+0444 for SENSOR_DEVICE_ATTR[_2]_RO, and 0200 for SENSOR_DEVICE_ATTR[_2]_WO.
+Standard functions, similar to DEVICE_ATTR_{RW,RO,WO}, have _show and _store
+appended to the provided function name.
+
+SENSOR_DEVICE_ATTR and its variants define a struct sensor_device_attribute
+variable. This structure has the following fields.
 
 struct sensor_device_attribute {
 	struct device_attribute dev_attr;
@@ -320,8 +328,8 @@ You can use to_sensor_dev_attr to get the pointer to this structure from the
 attribute read or write function. Its parameter is the device to which the
 attribute is attached.
 
-SENSOR_DEVICE_ATTR_2 defines a struct sensor_device_attribute_2 variable,
+SENSOR_DEVICE_ATTR_2 and its variants define a struct sensor_device_attribute_2
-which is defined as follows.
+variable, which is defined as follows.
 
 struct sensor_device_attribute_2 {
 	struct device_attribute dev_attr;

include/linux/hwmon-sysfs.h

@@ -33,10 +33,28 @@ struct sensor_device_attribute{
 	{ .dev_attr = __ATTR(_name, _mode, _show, _store),	\
 	  .index = _index }
 
+#define SENSOR_ATTR_RO(_name, _func, _index)			\
+	SENSOR_ATTR(_name, 0444, _func##_show, NULL, _index)
+
+#define SENSOR_ATTR_RW(_name, _func, _index)			\
+	SENSOR_ATTR(_name, 0644, _func##_show, _func##_store, _index)
+
+#define SENSOR_ATTR_WO(_name, _func, _index)			\
+	SENSOR_ATTR(_name, 0200, NULL, _func##_store, _index)
+
 #define SENSOR_DEVICE_ATTR(_name, _mode, _show, _store, _index)	\
 struct sensor_device_attribute sensor_dev_attr_##_name		\
 	= SENSOR_ATTR(_name, _mode, _show, _store, _index)
 
+#define SENSOR_DEVICE_ATTR_RO(_name, _func, _index)		\
+	SENSOR_DEVICE_ATTR(_name, 0444, _func##_show, NULL, _index)
+
+#define SENSOR_DEVICE_ATTR_RW(_name, _func, _index)		\
+	SENSOR_DEVICE_ATTR(_name, 0644, _func##_show, _func##_store, _index)
+
+#define SENSOR_DEVICE_ATTR_WO(_name, _func, _index)		\
+	SENSOR_DEVICE_ATTR(_name, 0200, NULL, _func##_store, _index)
+
 struct sensor_device_attribute_2 {
 	struct device_attribute dev_attr;
 	u8 index;
@@ -50,8 +68,29 @@ struct sensor_device_attribute_2 {
 	  .index = _index,					\
 	  .nr = _nr }
 
+#define SENSOR_ATTR_2_RO(_name, _func, _nr, _index)		\
+	SENSOR_ATTR_2(_name, 0444, _func##_show, NULL, _nr, _index)
+
+#define SENSOR_ATTR_2_RW(_name, _func, _nr, _index)		\
+	SENSOR_ATTR_2(_name, 0644, _func##_show, _func##_store, _nr, _index)
+
+#define SENSOR_ATTR_2_WO(_name, _func, _nr, _index)		\
+	SENSOR_ATTR_2(_name, 0200, NULL, _func##_store, _nr, _index)
+
 #define SENSOR_DEVICE_ATTR_2(_name,_mode,_show,_store,_nr,_index)	\
 struct sensor_device_attribute_2 sensor_dev_attr_##_name		\
 	= SENSOR_ATTR_2(_name, _mode, _show, _store, _nr, _index)
 
+#define SENSOR_DEVICE_ATTR_2_RO(_name, _func, _nr, _index)		\
+	SENSOR_DEVICE_ATTR_2(_name, 0444, _func##_show, NULL,		\
+			     _nr, _index)
+
+#define SENSOR_DEVICE_ATTR_2_RW(_name, _func, _nr, _index)		\
+	SENSOR_DEVICE_ATTR_2(_name, 0644, _func##_show, _func##_store,	\
+			     _nr, _index)
+
+#define SENSOR_DEVICE_ATTR_2_WO(_name, _func, _nr, _index)		\
+	SENSOR_DEVICE_ATTR_2(_name, 0200, NULL, _func##_store,		\
+			     _nr, _index)
+
 #endif /* _LINUX_HWMON_SYSFS_H */