linux-kernel - Re: [RFC PATCH v2 01/17] OPP: Allow to request stub voltage regulators

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Date:   Mon, 22 Oct 2018 17:02:24 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Rob Herring <robh+dt@...nel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Nishanth Menon <nm@...com>, Stephen Boyd <sboyd@...nel.org>,
        Marcel Ziswiler <marcel.ziswiler@...adex.com>,
        linux-tegra@...r.kernel.org, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v2 01/17] OPP: Allow to request stub voltage
 regulators

On 22-10-18, 14:29, Dmitry Osipenko wrote:
> On 10/22/18 8:36 AM, Viresh Kumar wrote:
> > On 21-10-18, 23:54, Dmitry Osipenko wrote:
> >> Voltage regulators may be not available on some variations of HW, allow to
> >> request stub voltage regulators by OPP core in a such case to reduce code
> >> churning within drivers.
> >>
> >> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> >> ---
> >>  drivers/cpufreq/cpufreq-dt.c | 2 +-
> >>  drivers/cpufreq/ti-cpufreq.c | 3 ++-
> >>  drivers/opp/core.c           | 9 +++++++--
> >>  include/linux/pm_opp.h       | 4 ++--
> >>  4 files changed, 12 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
> >> index e58bfcb1169e..6ebca472ec76 100644
> >> --- a/drivers/cpufreq/cpufreq-dt.c
> >> +++ b/drivers/cpufreq/cpufreq-dt.c
> >> @@ -196,7 +196,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
> >>  	 */
> >>  	name = find_supply_name(cpu_dev);
> >>  	if (name) {
> >> -		opp_table = dev_pm_opp_set_regulators(cpu_dev, &name, 1);
> >> +		opp_table = dev_pm_opp_set_regulators(cpu_dev, &name, 1, false);
> >>  		if (IS_ERR(opp_table)) {
> >>  			ret = PTR_ERR(opp_table);
> >>  			dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
> > 
> > Have you actually tested this stuff ? The cpufreq-dt driver will
> > probably fail to probe if the CPU node has a "-supply" property, but
> > no regulator matching that.
> > 
> 
> Please notice that this patch doesn't change the original behaviour
> and I suppose that failing in a case of missing regulator is the
> expected behaviour for cpufreq-dt. Hence can't see any problem here.

So why have this patch then ?

-- 
viresh