From: Ulf Hansson <ulf.hansson@linaro.org>
To: Dave Gerlach <d-gerlach@ti.com>
Cc: Rob Herring <robh@kernel.org>,
Kevin Hilman <khilman@baylibre.com>,
Tero Kristo <t-kristo@ti.com>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Nishanth Menon <nm@ti.com>, Keerthy <j-keerthy@ti.com>,
Russell King <rmk+kernel@armlinux.org.uk>,
Sudeep Holla <sudeep.holla@arm.com>,
Santosh Shilimkar <ssantosh@kernel.org>,
Lokesh Vutla <lokeshvutla@ti.com>
Subject: Re: [PATCH v3 2/4] dt-bindings: Add TI SCI PM Domains
Date: Tue, 24 Jan 2017 11:03:48 +0100 [thread overview]
Message-ID: <CAPDyKFq3zjyubxf3wc1V+F2W3rbnjj4ObFnHFvda+wCs4rBtnw@mail.gmail.com> (raw)
In-Reply-To: <ec2f1697-4c60-fd88-6593-2a69ca7f5c83@ti.com>
On 23 January 2017 at 21:11, Dave Gerlach <d-gerlach@ti.com> wrote:
> On 01/20/2017 10:52 AM, Ulf Hansson wrote:
>>
>> [...]
>>
>>>>> Another option is create something new either common or TI SCI
>>>>> specific. It could be just a table of ids and phandles in the SCI
>>>>> node. I'm much more comfortable with an isolated property in one node
>>>>> than something scattered throughout the DT.
>>>>
>>>>
>>>> To me, this seems like the best possible solution.
>>>>
>>>> However, perhaps we should also consider the SCPI Generic power domain
>>>> (drivers/firmware/scpi_pm_domain.c), because I believe it's closely
>>>> related.
>>>> To change the power state of a device, this PM domain calls
>>>> scpi_device_set|get_power_state() (drivers/firmware/arm_scpi.c), which
>>>> also needs a device id as a parameter. Very similar to our case with
>>>> the TI SCI domain.
>>>>
>>>> Currently these SCPI device ids lacks corresponding DT bindings, so
>>>> the scpi_pm_domain tries to work around it by assigning ids
>>>> dynamically at genpd creation time.
>>>>
>>>> That makes me wonder, whether we should think of something
>>>> common/generic?
>>>
>>>
>>> When you say something common/generic, do you mean a better binding for
>>> genpd,
>>> or something bigger than that like a new driver? Because I do think a
>>> phandle
>>> cell left open for the genpd provider to interpret solves both the scpi
>>> and
>>> ti-sci problem we are facing here in the best way. Using generic PM
>>> domains lets
>>> us do exactly what we want apart from interpreting the phandle cell with
>>> our
>>> driver, and I feel like anything else we try at this point is just going
>>> to be
>>> to work around that. Is bringing back genpd xlate something we can
>>> discuss?
>>
>>
>> Bringing back xlate, how would that help? Wouldn't that just mean that
>> you will get one genpd per device? That's not an option, I think we
>> are all in agreement to that.
>
>
> Sure, perhaps the custom xlate wouldn't be the right way to do it, as we
> wouldn't be able to associate a device directly to a phandle, at least with
> how it was implemented before, but I think we can skip that entirely. Does
> opening up the interpretation of the cells of the 'power-domains' phandle
> not solve all of these issues? Is that out of the question?
>
> genpd_xlate_simple currently just makes sure the args_count of the
> 'power-domains' phandle was zero and bails if it was not. Why couldn't we
> remove this check and let the driver interpret it while still using
> of_genpd_add_provider_simple to register the provider? It's still a 'simple'
> provider from the perspective of the genpd framework and the actual pm
> domain mapping will not change, but now the driver can parse the cells and
> do whatever it needs to, such as reading a device id.
>
> I think that's a bit more flexible and will avoid breaking anything that is
> there today.
Would you mind providing an example? Perhaps also some code snippets
dealing with the parsing?
Kind regards
Uffe
next prev parent reply other threads:[~2017-01-24 10:03 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-04 20:55 [PATCH v3 0/4] ARM: K2G: Add support for TI-SCI Generic PM Domains Dave Gerlach
2017-01-04 20:55 ` [PATCH v3 1/4] PM / Domains: Add generic data pointer to genpd data struct Dave Gerlach
2017-01-04 20:55 ` [PATCH v3 2/4] dt-bindings: Add TI SCI PM Domains Dave Gerlach
2017-01-09 17:50 ` Rob Herring
2017-01-09 17:57 ` Dave Gerlach
2017-01-11 21:34 ` Rob Herring
2017-01-12 15:27 ` Dave Gerlach
2017-01-13 19:25 ` Rob Herring
2017-01-13 20:28 ` Dave Gerlach
2017-01-14 2:40 ` Rob Herring
2017-01-16 22:12 ` Dave Gerlach
2017-01-17 7:48 ` Tero Kristo
2017-01-17 23:37 ` Rob Herring
2017-01-18 0:07 ` Kevin Hilman
2017-01-18 23:03 ` Rob Herring
2017-01-20 14:00 ` Ulf Hansson
2017-01-20 14:18 ` Sudeep Holla
2017-01-20 14:20 ` Dave Gerlach
2017-01-20 16:52 ` Ulf Hansson
2017-01-23 20:11 ` Dave Gerlach
2017-01-24 10:03 ` Ulf Hansson [this message]
2017-01-25 16:59 ` Dave Gerlach
2017-01-25 21:13 ` Ulf Hansson
2017-01-25 22:32 ` Rob Herring
2017-01-26 15:09 ` Dave Gerlach
2017-01-26 16:00 ` Rob Herring
2017-01-04 20:55 ` [PATCH v3 3/4] soc: ti: Add ti_sci_pm_domains driver Dave Gerlach
2017-01-04 20:55 ` [PATCH v3 4/4] ARM: keystone: Drop PM domain support for k2g Dave Gerlach
2017-01-04 21:54 ` [PATCH v3 0/4] ARM: K2G: Add support for TI-SCI Generic PM Domains Santosh Shilimkar
2017-01-04 22:06 ` Dave Gerlach
2017-01-19 17:51 ` santosh.shilimkar
2017-01-19 18:59 ` Dave Gerlach
2017-01-19 19:04 ` Santosh Shilimkar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAPDyKFq3zjyubxf3wc1V+F2W3rbnjj4ObFnHFvda+wCs4rBtnw@mail.gmail.com \
--to=ulf.hansson@linaro.org \
--cc=d-gerlach@ti.com \
--cc=devicetree@vger.kernel.org \
--cc=j-keerthy@ti.com \
--cc=khilman@baylibre.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=lokeshvutla@ti.com \
--cc=nm@ti.com \
--cc=rjw@rjwysocki.net \
--cc=rmk+kernel@armlinux.org.uk \
--cc=robh@kernel.org \
--cc=ssantosh@kernel.org \
--cc=sudeep.holla@arm.com \
--cc=t-kristo@ti.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).