On Tue, 10 Sep 2019 11:21:56 +0100 Daniel Thompson daniel.thompson@linaro.org wrote:
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Is this needed?
This is a remove path, not a power management path, and we have no idea what the original status of the pin was anyway?
Looking at Ishdn on page 5 of the datasheet, switching it off everytime possible seems not needed. We would need to call chip_init() everytime we enable the gpio or live with default values. Therefore I did decide to not put it into any power management path. But switching it on and not switching it off feels so unbalanced.
Either the power consumed by the controller when strings aren't lit up matters, in which case the driver should implement proper power management or it doesn't matter and changing the pin state isn't needed.
I'm happy with either of the above but this looks like a third way, where eager users could hack in a bit of extra power management by forcing drivers to unbind.
I think I will take the simple way. I am quite sure that the power consumption with HWEN on and leds off does not matter. If someone later comes up and finds out that I misread the datasheet, things are prepared to be improved. At least the hardware can be properly described in the devicetree.
Regards, Andreas