From: Jon Hunter <jonathanh@nvidia.com>
To: Ulf Hansson <ulf.hansson@linaro.org>, Kevin Hilman <khilman@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
Rajendra Nayak <rnayak@codeaurora.org>
Subject: Re: [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains
Date: Wed, 16 Nov 2016 10:48:29 +0000 [thread overview]
Message-ID: <d961715d-820a-dd63-e3a9-c908ce465582@nvidia.com> (raw)
In-Reply-To: <63670abf-1d58-a7e3-6927-0c815d44d8a1@nvidia.com>
Hi Kevin, Ulf,
On 03/11/16 14:20, Jon Hunter wrote:
>
> On 11/10/16 10:15, Jon Hunter wrote:
>
> ...
>
>>>>> Second, another way of seeing this is: Depending on the current
>>>>> runtime selected configuration you need to re-configure the PM domain
>>>>> topology - but the device would still remain in the same PM domain.
>>>>>
>>>>> In other words, you would need to remove/add subdomain(s) depending on
>>>>> the selected configuration. Would that better reflect the HW?
>>>>
>>>> I am not 100% sure I follow what you are saying, but ultimately, I would
>>>> like to get to ...
>>>>
>>>> usb@70090000 {
>>>> compatible = "nvidia,tegra210-xusb";
>>>> ...
>>>> power-domains = <&pd_xusbhost>, <&pd_xusbss>;
>>>> };
>>>
>>> So, is this really is a proper description of the HW? Isn't it so,
>>> that the usb device always resides in one and the same PM domain?
>>
>> I guess technically, the usbhost controller resides in one partition and
>> the super-speed logic in another. So could the usbhost domain be the
>> primary? Possibly, but the device cannot be probed without both enabled.
>>
>>> Now, depending on the selected speed mode (superspeed) additional
>>> logic may needs to be powered on and configured for the usb device to
>>> work?
>>> Perhaps, one could consider those additional logics as a master/parent
>>> PM domain for the usb device's PM domain?
>>>
>>> Or this is not how the HW works? :-)
>>
>> It might be possible for this case, but to be honest, the more I think
>> about this, I do wonder if we need to be able to make the framework a
>> lot more flexible for devices that need multiple power-domains. In other
>> words, for devices that use multiple domains allow them to control them
>> similarly to what we do for regulators or clocks. So if there is more
>> than one defined, then the genpd core will not bind the device to the
>> pm-domain and let the driver handle it. This way if you do need more
>> granular control of the pm-domains in the driver you can do whatever you
>> need to.
>>
>> I know that Rajendra (CC'ed) was looking into whether he had a need to
>> control multiple power-domains individually from within the context of a
>> single device driver.
>
> So Rajendra commented to say that he does not see a need for individual
> control of power-domains for now, but a need for specifying multiple.
>
> One simple option would be to allow users to specify multiple and have
> the genpd core effectively ignore such devices and leave it to the
> driver to configure manually. I have been able to do this for XUSB by
> dynamically adding power-domains to the device.
>
> Let me know if you have any more thoughts on how we can do this.
Any more thoughts on this? Seems that there are a few others that would
be interested in supporting multiple domains for a device.
Cheers
Jon
--
nvpublic
next prev parent reply other threads:[~2016-11-16 10:48 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-20 10:28 [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains Jon Hunter
2016-09-20 10:28 ` [RFC PATCH 1/3] PM / Domains: Add helper functions for finding and attaching PM domains Jon Hunter
2016-09-20 10:28 ` [RFC PATCH 2/3] PM / Domains: Add support for devices with multiple domains Jon Hunter
2016-09-20 17:54 ` Jon Hunter
2016-09-21 8:53 ` Geert Uytterhoeven
2016-09-21 10:01 ` Jon Hunter
2016-09-21 14:37 ` Jon Hunter
2016-09-21 14:57 ` Geert Uytterhoeven
2016-09-23 12:57 ` Jon Hunter
2016-09-23 14:27 ` Geert Uytterhoeven
2016-09-30 8:05 ` Jon Hunter
2016-10-07 9:14 ` Kevin Hilman
2016-10-10 11:24 ` Jon Hunter
2016-09-20 10:28 ` [RFC PATCH 3/3] dt-bindings: Add support for devices with multiple PM domains Jon Hunter
2016-10-06 6:04 ` [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains Rajendra Nayak
2016-10-06 8:25 ` Jon Hunter
2016-10-06 8:43 ` Rajendra Nayak
2016-10-31 10:44 ` Jon Hunter
2016-11-02 8:56 ` Rajendra Nayak
2016-11-16 13:11 ` Ulf Hansson
2016-11-17 2:31 ` Rajendra Nayak
2016-11-17 15:39 ` Stanimir Varbanov
2016-11-22 13:05 ` Ulf Hansson
2016-11-23 3:48 ` Rajendra Nayak
2016-10-06 12:22 ` Ulf Hansson
2016-10-10 11:18 ` Jon Hunter
2016-10-10 14:04 ` Ulf Hansson
2016-10-11 9:15 ` Jon Hunter
2016-11-03 14:20 ` Jon Hunter
2016-11-16 10:48 ` Jon Hunter [this message]
2016-11-16 12:53 ` Rafael J. Wysocki
2016-11-22 11:12 ` Jon Hunter
2016-11-22 13:31 ` Ulf Hansson
2016-11-22 14:28 ` Jon Hunter
2016-11-22 18:26 ` Kevin Hilman
2016-11-22 18:41 ` Jon Hunter
2016-11-24 2:30 ` Stephen Boyd
2016-11-29 11:33 ` Marek Szyprowski
2016-12-15 11:38 ` Jon Hunter
2016-11-22 21:55 ` Rafael J. Wysocki
2016-11-23 9:29 ` Jon Hunter
2016-11-23 13:15 ` Rafael J. Wysocki
2017-02-28 15:18 ` Jon Hunter
2017-02-28 15:29 ` Geert Uytterhoeven
2017-03-13 9:37 ` Jon Hunter
2017-03-13 11:45 ` Ulf Hansson
2017-03-13 14:09 ` Jon Hunter
2017-03-13 14:19 ` Geert Uytterhoeven
2017-03-13 14:27 ` Jon Hunter
2017-03-13 14:38 ` Geert Uytterhoeven
2017-03-13 14:51 ` Jon Hunter
2017-03-13 14:42 ` Ulf Hansson
2017-03-15 8:57 ` Jon Hunter
2017-03-15 3:47 ` Nayak, Rajendra
2017-03-15 9:03 ` Jon Hunter
2017-03-01 6:19 ` Rajendra Nayak
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