Hi Tomi,

On Tuesday 20 November 2012 22:48:18 Tomi Valkeinen wrote:

I guess there's a reason, but the above looks a bit inconsistent. For
gpio you define the gpio resource inside the step. For power and pwm the
resource is defined before the steps. Why wouldn't "pwm = <&pwm 2
5000000>;" work in step2?

That's mostly a framework issue. Most frameworks do not export a function that 
allow to dereference a phandle - they expect resources to be declared right 
under the device node and accessed by name through foo_get(device, name). So 
using phandles in power sequences would require to export these additional 
functions and also opens the door to some inconsistencies - for instance, your 
PWM phandle could be referenced a second time in the sequence with a different 
period - how do you know that these are actually referring the same PWM 
device?

quoted

+When a power sequence is run, its steps is executed one after the other
until +one step fails or the end of the sequence is reached.

The document doesn't give any hint of what the driver should do if
running the power sequence fails. Run the "opposite" power sequence?
Will that work for all resources? I'm mainly thinking of a case where
each enable of the resource should be matched by a disable, i.e. you
can't call disable if no enable was called.

We discussed that issue already (around v5 I think) and the conclusion was 
that it should be up to the driver. When we simply enable/disable resources it 
is easy to revert, but in the future non-boolean properties will likely be 
introduced, and these cannot easily be reverted. Moreover some drivers might 
have more complex recovery needs. This deserves more discussion I think, as 
I'd like to have some "generic" recovery mechanism that covers most of the 
cases.

Alex.