Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage reset controllers

[Vivek Gautam]

On 04/25/2017 04:24 PM, Jon Hunter wrote:
> On 25/04/17 11:33, Philipp Zabel wrote:
> > On Tue, 2017-04-25 at 11:05 +0100, Jon Hunter wrote:
> > > On 25/04/17 05:15, Vivek Gautam wrote:
> > > > On 04/24/2017 06:15 PM, Jon Hunter wrote:
> > > > > On 18/04/17 12:21, Vivek Gautam wrote:
> > > > > > Make use of reset_control_array_*() set of APIs to manage
> > > > > > an array of reset controllers available with the device.
> > > > > Before we apply this patch, I need to check to see if the order of the
> > > > > resets managed by the PMC driver matter. Today the order of the resets
> > > > > is determined by the order they appear in the DT node and although the
> > > > > new APIs work in the same way they do not guarantee this. So let me
> > > > > check to see if we can any concerns about ordering here. Otherwise would
> > > > > be nice to use these APIs.
> > > > Right, that will be perfect.
> > > So I don't see any restrictions here and so I think this change is fine.
> > Thank you for checking.
> >
> > > BTW, for the DT case, is there any reason why we don't just say the
> > > order will be determine by the order the resets are list in the DT node?
> > I'd rather not make any promises, so I don't have to care about keeping
> > them. This makes it easier to think about and allows for more freedom in
> > changing the core code if needed.
> >
> > What if in the future there is a use case for enabling a bunch of resets
> > by flipping a number of bits in a single register at the same time? Or
> > if people accidentally depend on the ordering when in reality there is a
> > small delay necessary between assertions that just happens to be hidden
> > by the framework overhead?
> >
> > If there is a use case for an array of reset controls that must be
> > (de)asserted in a fixed order and doesn't need any delay between the
> > steps and is not suitable to be described by named resets for some
> > reason, we can discuss this. Until then, I'm happy that tegra pmc can
> > handle arrays without any particular ordering.
> OK, makes sense.

Thanks Jon for testing this.

Best Regards
Vivek
> Thanks
> Jon

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