9 Mar
2022
9 Mar
'22
9:55 p.m.
On Wed, Mar 09, 2022 at 08:16:07PM +0000, John Keeping wrote:
On Wed, Mar 09, 2022 at 04:28:30PM +0000, Mark Brown wrote:
I think the device tree binding needs to be clarified here to be explicit about this since there's obviously some room for user confusion here. We can probably get away with a change at this point since it's not hit a release but we do need to try to avoid the situation where any other implementations use active high polarity for the bindings.
Taking a quick survey of the other devices that have a pdn-gpios property:
- tvp5150 is correct with the driver setting 0 to make the device active
- tas571x also sets 0 to make the device active
- ak4375 uses the opposite sense setting PDN = 1 to make the device active; this has no in-tree users and was merged as part of v5.17-rc1 so it's not in a released kernel yet
Sure, I still think it would be good to update the binding document to clarify things as part of your patch - the binding currently just has it as the "pdn" pin not the /pdn pin or anything.