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linux-next/Documentation/devicetree/bindings/leds/common.txt
Jacek Anaszewski aa14318aa0 DT: leds: Improve description of flash LEDs related properties
1. Since max-microamp property has had no users so far, then rename
   it to more descriptive led-max-microamp.
2. Since flash-timeout-us property has had no users so far, then rename
   it to more accurate flash-max-timeout-us.
3. Describe led-max-microamp property as mandatory for specific board
   configurations.
4. Make flash-max-microamp and flash-max-timeout-us properties mandatory
   for devices with configurable flash current and flash timeout settings
   respectively.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: devicetree@vger.kernel.org
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
2015-08-28 14:05:55 +02:00

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Common leds properties.
LED and flash LED devices provide the same basic functionality as current
regulators, but extended with LED and flash LED specific features like
blinking patterns, flash timeout, flash faults and external flash strobe mode.
Many LED devices expose more than one current output that can be connected
to one or more discrete LED component. Since the arrangement of connections
can influence the way of the LED device initialization, the LED components
have to be tightly coupled with the LED device binding. They are represented
by child nodes of the parent LED device binding.
Optional properties for child nodes:
- led-sources : List of device current outputs the LED is connected to. The
outputs are identified by the numbers that must be defined
in the LED device binding documentation.
- label : The label for this LED. If omitted, the label is taken from the node
name (excluding the unit address). It has to uniquely identify
a device, i.e. no other LED class device can be assigned the same
label.
- linux,default-trigger : This parameter, if present, is a
string defining the trigger assigned to the LED. Current triggers are:
"backlight" - LED will act as a back-light, controlled by the framebuffer
system
"default-on" - LED will turn on (but for leds-gpio see "default-state"
property in Documentation/devicetree/bindings/gpio/led.txt)
"heartbeat" - LED "double" flashes at a load average based rate
"ide-disk" - LED indicates disk activity
"timer" - LED flashes at a fixed, configurable rate
- led-max-microamp : Maximum LED supply current in microamperes. This property
can be made mandatory for the board configurations
introducing a risk of hardware damage in case an excessive
current is set.
For flash LED controllers with configurable current this
property is mandatory for the LEDs in the non-flash modes
(e.g. torch or indicator).
Required properties for flash LED child nodes:
- flash-max-microamp : Maximum flash LED supply current in microamperes.
- flash-max-timeout-us : Maximum timeout in microseconds after which the flash
LED is turned off.
For controllers that have no configurable current the flash-max-microamp
property can be omitted.
For controllers that have no configurable timeout the flash-max-timeout-us
property can be omitted.
Examples:
system-status {
label = "Status";
linux,default-trigger = "heartbeat";
...
};
camera-flash {
label = "Flash";
led-sources = <0>, <1>;
led-max-microamp = <50000>;
flash-max-microamp = <320000>;
flash-max-timeout-us = <500000>;
};