On 04/10/2019 13:39, Mark Brown wrote:
On Thu, Oct 03, 2019 at 10:27:26PM +0200, Jacek Anaszewski wrote:
On 10/3/19 9:41 PM, Mark Brown wrote:
Why would we want to do that? We'd continue to support only DT systems, just with code that's less obviously DT only and would need to put checks in. I'm not seeing an upside here.
For instance few weeks ago we had a patch [0] in the LED core switching from using struct device's of_node property to fwnode for conveying device property data. And this transition to fwnode property API can be observed as a frequent pattern across subsystems.
For most subsystems the intent is to reuse DT bindings on embedded ACPI systems via _DSD.
Recently there is an ongoing effort aiming to add generic support for handling regulators in the LED core [1], but it turns out to require bringing back initialization of of_node property for devm_regulator_get_optional() to work properly.
Consumers should just be able to request a regulator without having to worry about how that's being provided - they should have no knowledge at all of firmware bindings or platform data for defining this. If they do that suggests there's an abstraction issue somewhere, what makes you think that doing something with of_node is required?
The regulator core accesses consumer->of_node to get a phandle to a regulator's node. The trouble arises from the fact that the LED core does not populate of_node anymore, instead it populates fwnode. This allows the LED core to be agnostic of ACPI or OF to get the properties of a LED.
IMO it is better to populate both of_node and fwnode in the LED core at the moment. It has already been fixed this way for the platform driver [0], MTD [1] and PCI-OF [2].
Further, unless you have LEDs that work without power you probably shouldn't be using _get_optional() for their supply. That interface is intended only for supplies that may be physically absent.
Not all LEDs have a regulator to provide the power. The power can be supplied by the LED controller for example.
[0] f94277af03ead0d3bf2 of/platform: Initialise dev->fwnode appropriately
[1] c176c6d7e932662668 mfd: core: Set fwnode for created devices
[2] 9b099a6c75e4ddceea PCI: OF: Initialize dev->fwnode appropriately