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

[Jon Hunter]

On 25/04/17 12:06, Vivek Gautam wrote:
> 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.

Not tested yet :-)

However, I will test this just to confirm. Are you planning on sending
out a v4 soon?

Jon

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