All of lore.kernel.org
 help / color / mirror / Atom feed
From: Viresh Kumar <viresh.kumar@linaro.org>
To: Dave Gerlach <d-gerlach@ti.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
	Rafael Wysocki <rjw@rjwysocki.net>, Nishanth Menon <nm@ti.com>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Lists linaro-kernel <linaro-kernel@lists.linaro.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Rob Herring <robh@kernel.org>, Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH V2 0/8] PM / OPP: Multiple regulator support
Date: Wed, 26 Oct 2016 08:51:24 +0530	[thread overview]
Message-ID: <20161026032124.GG9162@vireshk-i7> (raw)
In-Reply-To: <4059f5a9-5308-8a5e-827b-4f822d9049d2@ti.com>

On 25-10-16, 16:13, Dave Gerlach wrote:
> I think what you have shared below is a good safety check but if I rename
> the regulator properties in the DT for the cpu (to vdd and vbb, meaning
> cpufreq detects no regulator) and do *not* call dev_pm_opp_set_regulators
> before cpufreq-dt probes we fail before we even get to that point:
> 
> [16.946] cpu cpu0: opp_parse_supplies: Invalid number of elements in
> opp-microvolt property (6) with supplies (1)
> [16.967] cpu cpu0: _of_add_opp_table_v2: Failed to add OPP, -22
> [16.982] cpu cpu0: dev_pm_opp_get_opp_count: OPP table not found (-19)
> [16.982] cpu cpu0: OPP table is not ready, deferring probe
> 
> This failure is because opp_parse_supplies assumes a count of 1 regulator if
> no regulators at all are present and then hard fails if too many voltages
> have been passed for each OPP.

Exactly. And yes this is intentional.

> It seems we need a check much earlier similar
> to what you suggested below to allow us to defer if an OPP has supplied
> voltages but no regulator has been registered with the system. I think this
> is reasonable even for the 1 regulator case, no?

No.

OPP core needs to know about regulators only if the user drivers want it to
manage DVFS. It is still possible for cpufreq drivers to use OPP framework for
managing the tables, but do the real DVFS stuff themselves. That's why it is not
compulsory in the code to set regulator names.

And its only wrong if dev_pm_opp_set_rate() is called without first setting the
regulators..

> cpufreq-dt won't handle this properly as is, but now that the opp core is
> evolving perhaps it makes sense to modify the resources_available check
> slightly to rely on the OPP core rather than just a dummy
> regulator_get_optional to see if the regulator is ready.

I am not sure yet on what to change there. You mean regarding multiple
regulators?

-- 
viresh

      reply	other threads:[~2016-10-26  3:21 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-20  8:44 [PATCH V2 0/8] PM / OPP: Multiple regulator support Viresh Kumar
2016-10-20  8:44 ` [PATCH V2 1/8] PM / OPP: Reword binding supporting multiple regulators per device Viresh Kumar
2016-10-24 22:48   ` Stephen Boyd
2016-10-24 22:48     ` Stephen Boyd
2016-10-20  8:44 ` [PATCH V2 2/8] PM / OPP: Don't use OPP structure outside of rcu protected section Viresh Kumar
2016-10-24 22:52   ` Stephen Boyd
2016-10-25  3:37     ` Viresh Kumar
2016-10-20  8:44 ` [PATCH V2 3/8] PM / OPP: Manage supply's voltage/current in a separate structure Viresh Kumar
2016-10-20  8:44 ` [PATCH V2 4/8] PM / OPP: Pass struct dev_pm_opp_supply to _set_opp_voltage() Viresh Kumar
2016-10-24 23:14   ` Stephen Boyd
2016-10-25  3:45     ` Viresh Kumar
2016-10-25 20:26       ` Stephen Boyd
2016-10-26  3:34         ` Viresh Kumar
2016-10-20  8:44 ` [PATCH V2 5/8] PM / OPP: Add infrastructure to manage multiple regulators Viresh Kumar
2016-10-21 22:32   ` Dave Gerlach
2016-10-21 22:32     ` Dave Gerlach
2016-10-24  3:35     ` Viresh Kumar
2016-10-25 16:49   ` Stephen Boyd
2016-10-26  6:05     ` Viresh Kumar
2016-11-10  1:37       ` Stephen Boyd
2016-10-20  8:45 ` [PATCH V2 6/8] PM / OPP: Separate out _generic_opp_set_rate() Viresh Kumar
2016-10-25 18:59   ` Stephen Boyd
2016-10-26  6:07     ` Viresh Kumar
2016-10-20  8:45 ` [PATCH V2 7/8] PM / OPP: Allow platform specific custom opp_set_rate() callbacks Viresh Kumar
2016-10-25 19:01   ` Stephen Boyd
2016-10-26  6:07     ` Viresh Kumar
2016-10-20  8:45 ` [PATCH V2 8/8] PM / OPP: Don't WARN on multiple calls to dev_pm_opp_set_regulators() Viresh Kumar
2016-10-25 19:01   ` Stephen Boyd
2016-10-21 13:39 ` [PATCH V2 0/8] PM / OPP: Multiple regulator support Rafael J. Wysocki
2016-10-21 15:40   ` Viresh Kumar
2016-10-24  1:08     ` Dave Gerlach
2016-10-24  4:26       ` Viresh Kumar
2016-10-25 21:13         ` Dave Gerlach
2016-10-26  3:21           ` Viresh Kumar [this message]

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=20161026032124.GG9162@vireshk-i7 \
    --to=viresh.kumar@linaro.org \
    --cc=broonie@kernel.org \
    --cc=d-gerlach@ti.com \
    --cc=linaro-kernel@lists.linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=nm@ti.com \
    --cc=rafael@kernel.org \
    --cc=rjw@rjwysocki.net \
    --cc=robh@kernel.org \
    --cc=sboyd@codeaurora.org \
    --cc=vincent.guittot@linaro.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.