Re: Any news on Runtime Interpreted Power Sequences

From: Alex Courbot
Date: Fri Oct 25 2013 - 02:24:01 EST

Hi Neil,

On 10/25/2013 09:22 AM, NeilBrown wrote:
I'm wondering if there was any news on the Runtime Interpreted Power
The most recent news I can find is
where you say they might be ready for 3.11. Clearly that didn't work
(predictions being hard, especially about the future).

I'm really keen to see them turning into a reality and I gather others are
too. So ... can we hope?

A prerequisite of power sequences was to merge the gpiod interface, and this is finally happening. It took much longer than I wanted, sorry about that.

Logically speaking nothing should now stand in the way of a new version of the power sequences. Expected maybe my own skepticism about them.

The first version of the power seqs is mainly the result of my misunderstanding of the device tree. Reconsidering it now, if we strip the DT support away power seqs would just become a simplified way to describe how to power a device up and down. In other words, it would be another way to express what can be expressed with C code and would not bring any additional flexibility that DT-described power seqs would have (and I say this totally convinced now that power sequences in the device tree were a bad idea).

The advantage I could see is that using power sequences we could get rid of the cumbersome and mistake-prone error checking code which is basically the same for most devices. You would just need to describe what you want to activate, and in which order, and the power seqs framework would catch and report any error.

I'm not sure if this is a sufficient reason to introduce another framework into the kernel, but if this is deemed a good reason by more experienced people then I'm ok to give it a shot. If you have other motivations for this, please also state them so I can get the whole picture. Maybe I just need to be a little bit more motivated about this idea myself. :)


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