From: Dmitry Osipenko <digetx@gmail.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Rob Herring <robh+dt@kernel.org>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Nishanth Menon <nm@ti.com>, Stephen Boyd <sboyd@kernel.org>,
Marcel Ziswiler <marcel.ziswiler@toradex.com>,
linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v2 01/17] OPP: Allow to request stub voltage regulators
Date: Mon, 22 Oct 2018 15:12:08 +0300 [thread overview]
Message-ID: <29f893be-feed-c4c5-8468-51f7228dd468@gmail.com> (raw)
In-Reply-To: <20181022113224.b5fiebgy2aap66nd@vireshk-i7>
On 10/22/18 2:32 PM, Viresh Kumar wrote:
> 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@gmail.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 ?
Because there is one Tegra20 board (tegra20-trimslice) that doesn't declare necessary regulators, but we want to have CPU frequency scaling. I couldn't find board schematics and so don't know if CPU / CORE voltages are fixed on Trim-Slice or it is just preferable not to have DVFS for that board, it is an outlet-powered device [0]. Hence tegra20-cpufreq driver will request a dummy regulators when appropriate.
[0] http://www.compulab.co.il/utilite-computer/web/trim-slice
next prev parent reply other threads:[~2018-10-22 12:12 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-21 20:54 [RFC PATCH v2 00/17] CPUFREQ OPP's, DVFS and Tegra30 support by tegra20-cpufreq driver Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 01/17] OPP: Allow to request stub voltage regulators Dmitry Osipenko
2018-10-22 5:36 ` Viresh Kumar
2018-10-22 11:29 ` Dmitry Osipenko
2018-10-22 11:32 ` Viresh Kumar
2018-10-22 12:12 ` Dmitry Osipenko [this message]
2018-10-24 6:41 ` Viresh Kumar
2018-10-26 12:03 ` Dmitry Osipenko
2018-10-26 15:37 ` Lucas Stach
2018-10-28 12:58 ` Dmitry Osipenko
2018-10-29 6:53 ` Viresh Kumar
2018-10-30 15:48 ` Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 02/17] soc/tegra: fuse: Export tegra_get_chip_id() Dmitry Osipenko
2018-10-21 21:33 ` Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 03/17] dt-bindings: cpufreq: Add binding for NVIDIA Tegra20/30 Dmitry Osipenko
2018-11-05 21:30 ` Rob Herring
2018-11-08 16:48 ` Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 04/17] cpufreq: tegra20: Support OPP, thermal cooling, DVFS and Tegra30 Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 05/17] ARM: tegra: Create tegra20-cpufreq device on Tegra30 Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 06/17] ARM: dts: tegra20: Add CPU Operating Performance Points Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 07/17] ARM: dts: tegra30: " Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 08/17] ARM: dts: tegra20: colibri: Setup voltage regulators for DVFS Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 09/17] ARM: dts: tegra20: harmony: " Dmitry Osipenko
2018-10-22 15:33 ` Stephen Warren
2018-10-22 22:59 ` Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 10/17] ARM: dts: tegra20: paz00: " Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 11/17] ARM: dts: tegra20: seaboard: " Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 12/17] ARM: dts: tegra20: tamonten: " Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 13/17] ARM: dts: tegra20: ventana: " Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 14/17] ARM: dts: tegra30: apalis: " Dmitry Osipenko
2018-10-21 20:54 ` [RFC PATCH v2 15/17] ARM: dts: tegra30: beaver: " Dmitry Osipenko
2018-10-21 20:55 ` [RFC PATCH v2 16/17] ARM: dts: tegra30: cardhu: " Dmitry Osipenko
2018-10-21 20:55 ` [RFC PATCH v2 17/17] ARM: dts: tegra30: colibri: " Dmitry Osipenko
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