ACPI: thinkpad-acpi: add sysfs led class support to thinkpad leds (v3.2)
Add a sysfs led class interface to the led subdriver.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index af1f2bc..73b80a7 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -876,28 +876,63 @@
in newer ThinkPads it is just a compatibility layer. Do not use it, it is
exported just as a debug tool.
-LED control -- /proc/acpi/ibm/led
----------------------------------
+LED control
+-----------
-Some of the LED indicators can be controlled through this feature. The
-available commands are:
+procfs: /proc/acpi/ibm/led
+sysfs attributes: as per led class, see below for names
+
+Some of the LED indicators can be controlled through this feature. On
+some older ThinkPad models, it is possible to query the status of the
+LED indicators as well. Newer ThinkPads cannot query the real status
+of the LED indicators.
+
+procfs notes:
+
+The available commands are:
echo '<led number> on' >/proc/acpi/ibm/led
echo '<led number> off' >/proc/acpi/ibm/led
echo '<led number> blink' >/proc/acpi/ibm/led
The <led number> range is 0 to 7. The set of LEDs that can be
-controlled varies from model to model. Here is the mapping on the X40:
+controlled varies from model to model. Here is the common ThinkPad
+mapping:
0 - power
1 - battery (orange)
2 - battery (green)
- 3 - UltraBase
+ 3 - UltraBase/dock
4 - UltraBay
+ 5 - UltraBase battery slot
+ 6 - (unknown)
7 - standby
All of the above can be turned on and off and can be made to blink.
+sysfs notes:
+
+The ThinkPad LED sysfs interface is described in detail by the led class
+documentation, in Documentation/leds-class.txt.
+
+The leds are named (in LED ID order, from 0 to 7):
+"tpacpi::power", "tpacpi:orange:batt", "tpacpi:green:batt",
+"tpacpi::dock_active", "tpacpi::bay_active", "tpacpi::dock_batt",
+"tpacpi::unknown_led", "tpacpi::standby".
+
+Due to limitations in the sysfs led class, if the status of the LED
+indicators cannot be read due to an error, thinkpad-acpi will report it as
+a brightness of zero (same as LED off).
+
+If the thinkpad firmware doesn't support reading the current status,
+trying to read the current LED brightness will just return whatever
+brightness was last written to that attribute.
+
+These LEDs can blink using hardware acceleration. To request that a
+ThinkPad indicator LED should blink in hardware accelerated mode, use the
+"timer" trigger, and leave the delay_on and delay_off parameters set to
+zero (to request hardware acceleration autodetection).
+
ACPI sounds -- /proc/acpi/ibm/beep
----------------------------------
