Adding Mark B and Liam...

On Mon, Jan 12, 2015 at 10:10 AM, Jacek Anaszewski
[off-list ref] wrote:

On 01/12/2015 02:52 PM, Rob Herring wrote:

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On Mon, Jan 12, 2015 at 2:32 AM, Jacek Anaszewski
[off-list ref] wrote:

quoted

On 01/09/2015 07:33 PM, Rob Herring wrote:

quoted

On Fri, Jan 9, 2015 at 9:22 AM, Jacek Anaszewski
[off-list ref] wrote:

quoted

Add a property for defining the device outputs the LED
represented by the DT child node is connected to.

[...]

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b/Documentation/devicetree/bindings/leds/common.txt
index a2c3f7a..29295bf 100644

--- a/Documentation/devicetree/bindings/leds/common.txt
+++ b/Documentation/devicetree/bindings/leds/common.txt

@@ -1,6 +1,10 @@
   Common leds properties.

   Optional properties for child nodes:
+- led-sources : Array of bits signifying the LED current regulator

outputs the
+               LED represented by the child node is connected to (1 -
the LED
+               is connected to the output, 0 - the LED isn't connected
to the
+               output).

Sorry, I just don't understand this.

In some Flash LED devices one LED can be connected to one or more
electric current outputs, which allows for multiplying the maximum
current allowed for the LED. Each sub-LED is represented by a child
node in the DT binding of the Flash LED device and it needs to declare
which outputs it is connected to. In the example below the led-sources
property is a two element array, which means that the flash LED device
has two current outputs, and the bits signify if the LED is connected
to the output.

Sounds like a regulator for which we already have bindings for and we
have a driver for regulator based LEDs (but no binding for it).

Do you think of drivers/leds/leds-regulator.c driver? This driver just
allows for registering an arbitrary regulator device as a LED subsystem
device.

There are however devices that don't fall into this category, i.e. they
have many outputs, that can be connected to a single LED or to many LEDs
and the driver has to know what is the actual arrangement.

We may need to extend the regulator binding slightly and allow for
multiple phandles on a supply property, but wouldn't something like
this work:

led-supply = <&led-reg0>, <&led-reg1>, <&led-reg2>, <&led-reg3>;

The shared source is already supported by the regulator binding.

Rob

quoted

Please use the regulator binding.

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Do your doubts stem from the ambiguity of the word "current" or the
form of the description itself is unclear? Probably there should be
explicit explanation added that the size of the array depends on the
number of current outputs of the flash LED device.

The size of the array and meaning of array indexes was not clear.

What about this:

led-sources : Array of connection states between all LED current
              sources exposed by the device and this LED (1 - this LED
              is connected to the current output with index N, 0 -
              this LED isn't connected to the current output with
              index N); the mapping of N-th element of the array to the
              physical device output should be defined in the LED
              driver binding.


--
Best Regards,
Jacek Anaszewski