thermal: update the documentation

Update the documentation for the thermal driver hwmon sys I/F.

Change the ACPI thermal zone type to be consistent with hwmon.

Signed-off-by: Zhang Rui <[e-mail]>
Acked-by: Jean Delvare <[e-mail]>
Signed-off-by: Len Brown <[e-mail]>

Documentation/thermal/sysfs-api.txt

···
 RO	read only value
 RW	read/write value
 
-All thermal sysfs attributes will be represented under /sys/class/thermal
+Thermal sysfs attributes will be represented under /sys/class/thermal.
+Hwmon sysfs I/F extension is also available under /sys/class/hwmon
+if hwmon is compiled in or built as a module.
 
 Thermal zone device sys I/F, created once it's registered:
-|thermal_zone[0-*]:
+/sys/class/thermal/thermal_zone[0-*]:
 	|-----type:			Type of the thermal zone
 	|-----temp:			Current temperature
 	|-----mode:			Working mode of the thermal zone
···
 	|-----trip_point_[0-*]_type:	Trip point type
 
 Thermal cooling device sys I/F, created once it's registered:
-|cooling_device[0-*]:
+/sys/class/thermal/cooling_device[0-*]:
 	|-----type :			Type of the cooling device(processor/fan/...)
 	|-----max_state:		Maximum cooling state of the cooling device
 	|-----cur_state:		Current cooling state of the cooling device
···
 They are created/removed for each
 thermal_zone_bind_cooling_device/thermal_zone_unbind_cooling_device successful execution.
 
-|thermal_zone[0-*]
+/sys/class/thermal/thermal_zone[0-*]
 	|-----cdev[0-*]:		The [0-*]th cooling device in the current thermal zone
 	|-----cdev[0-*]_trip_point:	Trip point that cdev[0-*] is associated with
 
+Besides the thermal zone device sysfs I/F and cooling device sysfs I/F,
+the generic thermal driver also creates a hwmon sysfs I/F for each _type_ of
+thermal zone device. E.g. the generic thermal driver registers one hwmon class device
+and build the associated hwmon sysfs I/F for all the registered ACPI thermal zones.
+/sys/class/hwmon/hwmon[0-*]:
+	|-----name:			The type of the thermal zone devices.
+	|-----temp[1-*]_input:		The current temperature of thermal zone [1-*].
+	|-----temp[1-*]_critical:	The critical trip point of thermal zone [1-*].
+Please read Documentation/hwmon/sysfs-interface for additional information.
 
 ***************************
 * Thermal zone attributes *
···
 
 type				Strings which represent the thermal zone type.
 				This is given by thermal zone driver as part of registration.
-				Eg: "ACPI thermal zone" indicates it's a ACPI thermal device
+				Eg: "acpitz" indicates it's an ACPI thermal device.
+				In order to keep it consistent with hwmon sys attribute,
+				this should be a short, lowercase string,
+				not containing spaces nor dashes.
 				RO
 				Required
 
···
 /sys/class/thermal:
 
 |thermal_zone1:
-	|-----type:			ACPI thermal zone
+	|-----type:			acpitz
 	|-----temp:			37000
 	|-----mode:			kernel
 	|-----trip_point_0_temp:	100000
···
 	|-----type:			Fan
 	|-----max_state:		2
 	|-----cur_state:		0
+
+/sys/class/hwmon:
+
+|hwmon0:
+	|-----name:			acpitz
+	|-----temp1_input:		37000
+	|-----temp1_crit:		100000

drivers/acpi/thermal.c

···
 
 	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE &&
 			tz->trips.active[i].flags.valid; i++, trips++);
-	tz->thermal_zone = thermal_zone_device_register("ACPI thermal zone",
+	tz->thermal_zone = thermal_zone_device_register("acpitz",
 					trips, tz, &acpi_thermal_zone_ops);
 	if (IS_ERR(tz->thermal_zone))
 		return -ENODEV;