Dan,

On 08/08/2018 11:45 PM, Dan Murphy wrote:

Jacek

On 08/08/2018 04:09 PM, Jacek Anaszewski wrote:

quoted

Hi Dan,

On 08/08/2018 11:04 PM, Dan Murphy wrote:

quoted

On 08/08/2018 04:02 PM, Pavel Machek wrote:

quoted

Hi!

quoted

quoted

quoted

+	- #size-cells : 0
+	- control-bank-cfg - : Indicates which sink is connected to which control bank
+		0 - All HVLED outputs are controlled by bank A
+		1 - HVLED1 is controlled bank B, HVLED2/3 are controlled by bank A
+		2 - HVLED2 is controlled bank B, HVLED1/3 are controlled by bank A
+		3 - HVLED1/2 are controlled by bank B, HVLED3 is controlled by bank A
+		4 - HVLED3 is controlled by bank B, HVLED1/2 are controlled by bank A
+		5 - HVLED1/3 is controlled by bank B, HVLED2 is controlled by bank A
+		6 - (default) HVLED1 is controlled by bank A, HVLED2/3 are controlled by bank B
+		7 - All HVLED outputs are controlled by bank B

This is quite long way to describe a bitmask, no? Could we make
it so that control-bank-cfg is not needed?

The problem we have here is there is a potential to control
3 different LED string but only 2 sinks.  So control bank A can control 2 LED strings and control
bank b can control 1 LED string.  

Can we forget about the LED strings, and just expose the sinks as
Linux LED devices?

2 sinks 3 LED strings.  How do you know which LED string is which and what bank it belongs
to when setting the brightness.  Each Bank has a separate register for brightness control.

Just a blind shot, without going into details - could you please check
if led-sources property documented in the common LED bindings couldn't
help here?

I could change the name to led-sources.  But this part does not really follow the 1 output to a
1 LED string topology.

led-sources was designed for describing the topology where one LED can
be connected to more then one output, see bindings of
max77693-led (in Documentation/devicetree/bindings/mfd/max77693.txt).

Here the topology is a bit different - more than one LED (string) can be
connected to a single bank, but this is accomplished inside the chip.
Logically LEDs configured that way can be treated as a single LED
(string) connected to two outputs, and what follows they should be
described by a single DT child node.

led-sources will fit very well for this purpose. You could do
the following mapping:

0 - HVLED1
1 - HVLED2
2 - HVLED3

Then, in the child DT nodes you would use these identifiers to describe
the topology:

Following node would describe strings connected to the outputs
HVLED1 and HVLED2 controlled by bank A.

led@0 {
	reg = <0>;
	led-sources = <0>. <1>;
	label = "white:first_backlight_cluster";
	linux,default-trigger = "backlight";
};


IOW I agree with Pavel, but I propose to use already documented common
DT LED property.

-- 
Best regards,
Jacek Anaszewski