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

From	Jon Hunter <jonathanh@nvidia.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage reset controllers
Date	2017-04-25 13:00 +0200
Message-ID	<tA6mm-3Ce-13@gated-at.bofh.it> (permalink)
References	(1 earlier) <txzuy-5A7-25@gated-at.bofh.it> <tzLBg-72B-9@gated-at.bofh.it> <tA07g-87x-7@gated-at.bofh.it> <tA5zX-3kk-1@gated-at.bofh.it> <tA631-3ve-29@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

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

-- 
nvpublic

Thread

[PATCH V3 0/4] reset: APIs to manage a list of resets Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-18 13:30 +0200
  [PATCH V3 2/4] reset: Add APIs to manage array of resets Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-18 13:30 +0200
    Re: [PATCH V3 2/4] reset: Add APIs to manage array of resets Philipp Zabel <p.zabel@pengutronix.de> - 2017-04-19 12:40 +0200
      Re: [PATCH V3 2/4] reset: Add APIs to manage array of resets Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-19 14:00 +0200
  [PATCH V3 1/4] reset: Add API to count number of reset available with device Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-18 13:30 +0200
    Re: [PATCH V3 1/4] reset: Add API to count number of reset  available with device Philipp Zabel <p.zabel@pengutronix.de> - 2017-04-19 12:30 +0200
      Re: [PATCH V3 1/4] reset: Add API to count number of reset available  with device Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-19 13:50 +0200
  [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage reset controllers Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-18 13:30 +0200
    Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage  reset controllers Philipp Zabel <p.zabel@pengutronix.de> - 2017-04-19 12:50 +0200
    Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage  reset controllers Jon Hunter <jonathanh@nvidia.com> - 2017-04-24 14:50 +0200
      Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage  reset controllers Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-25 06:20 +0200
        Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage  reset controllers Jon Hunter <jonathanh@nvidia.com> - 2017-04-25 12:10 +0200
          Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage  reset controllers Philipp Zabel <p.zabel@pengutronix.de> - 2017-04-25 12:40 +0200
            Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage  reset controllers Jon Hunter <jonathanh@nvidia.com> - 2017-04-25 13:00 +0200
              Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage  reset controllers Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-25 13:10 +0200
                Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage  reset controllers Jon Hunter <jonathanh@nvidia.com> - 2017-04-25 13:20 +0200
                Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage  reset controllers Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-25 20:00 +0200
  [PATCH V3 3/4] usb: dwc3: of-simple: Add support to get resets for the device Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-18 13:30 +0200
    Re: [PATCH V3 3/4] usb: dwc3: of-simple: Add support to get resets  for the device Philipp Zabel <p.zabel@pengutronix.de> - 2017-04-19 12:40 +0200
      Re: [PATCH V3 3/4] usb: dwc3: of-simple: Add support to get resets  for the device Vivek Gautam <vivek.gautam@codeaurora.org> - 2017-04-19 14:10 +0200

csiph-web