hwmon: enhance the sysfs API for power meters

Augment the documentation of the hwmon sysfs API to accomodate ACPI power
meters and the current desired behavior of power capping hardware drivers.
Signed-off-by: NDarrick J. Wong <djwong@us.ibm.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/hwmon/sysfs-interface

@@ -353,10 +353,20 @@ power[1-*]_average		Average power use
 				Unit: microWatt
 				RO
 
-power[1-*]_average_interval	Power use averaging interval
+power[1-*]_average_interval	Power use averaging interval.  A poll
+				notification is sent to this file if the
+				hardware changes the averaging interval.
 				Unit: milliseconds
 				RW
 
+power[1-*]_average_interval_max	Maximum power use averaging interval
+				Unit: milliseconds
+				RO
+
+power[1-*]_average_interval_min	Minimum power use averaging interval
+				Unit: milliseconds
+				RO
+
 power[1-*]_average_highest	Historical average maximum power use
 				Unit: microWatt
 				RO
@@ -365,6 +375,18 @@ power[1-*]_average_lowest	Historical average minimum power use
 				Unit: microWatt
 				RO
 
+power[1-*]_average_max		A poll notification is sent to
+				power[1-*]_average when power use
+				rises above this value.
+				Unit: microWatt
+				RW
+
+power[1-*]_average_min		A poll notification is sent to
+				power[1-*]_average when power use
+				sinks below this value.
+				Unit: microWatt
+				RW
+
 power[1-*]_input		Instantaneous power use
 				Unit: microWatt
 				RO
@@ -381,6 +403,39 @@ power[1-*]_reset_history	Reset input_highest, input_lowest,
 				average_highest and average_lowest.
 				WO
 
+power[1-*]_accuracy		Accuracy of the power meter.
+				Unit: Percent
+				RO
+
+power[1-*]_alarm		1 if the system is drawing more power than the
+				cap allows; 0 otherwise.  A poll notification is
+				sent to this file when the power use exceeds the
+				cap.  This file only appears if the cap is known
+				to be enforced by hardware.
+				RO
+
+power[1-*]_cap			If power use rises above this limit, the
+				system should take action to reduce power use.
+				A poll notification is sent to this file if the
+				cap is changed by the hardware.  The *_cap
+				files only appear if the cap is known to be
+				enforced by hardware.
+				Unit: microWatt
+				RW
+
+power[1-*]_cap_hyst		Margin of hysteresis built around capping and
+				notification.
+				Unit: microWatt
+				RW
+
+power[1-*]_cap_max		Maximum cap that can be set.
+				Unit: microWatt
+				RO
+
+power[1-*]_cap_min		Minimum cap that can be set.
+				Unit: microWatt
+				RO
+
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