linux-kernel - Re: [PATCH v3 17/22] firmware: arm_scmi: add device power domain support using genpd

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Date:   Fri, 29 Sep 2017 14:40:49 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Sudeep Holla <sudeep.holla@....com>,
        ALKML <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        DTML <devicetree@...r.kernel.org>,
        Roy Franz <roy.franz@...ium.com>,
        Harb Abdulhamid <harba@...eaurora.org>,
        Nishanth Menon <nm@...com>, Arnd Bergmann <arnd@...db.de>,
        Loc Ho <lho@....com>, Alexey Klimov <alexey.klimov@....com>,
        Ryan Harkin <Ryan.Harkin@....com>,
        Jassi Brar <jassisinghbrar@...il.com>,
        Kevin Hilman <khilman@...libre.com>
Subject: Re: [PATCH v3 17/22] firmware: arm_scmi: add device power domain
 support using genpd



On 28/09/17 22:18, Ulf Hansson wrote:
> On 28 September 2017 at 15:11, Sudeep Holla <sudeep.holla@....com> wrote:
>> This patch hooks up the support for device power domain provided by
>> SCMI using the Linux generic power domain infrastructure.
>>
>> Cc: Kevin Hilman <khilman@...libre.com>
>> Cc: Ulf Hansson <ulf.hansson@...aro.org>
>> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
>> ---
>>  drivers/firmware/Kconfig                   |  13 +++
>>  drivers/firmware/arm_scmi/Makefile         |   1 +
>>  drivers/firmware/arm_scmi/scmi_pm_domain.c | 134 +++++++++++++++++++++++++++++
>>  3 files changed, 148 insertions(+)
>>  create mode 100644 drivers/firmware/arm_scmi/scmi_pm_domain.c
>>

[...]

>> +       for (i = 0; i < num_domains; i++, scmi_pd++) {
>> +               domains[i] = &scmi_pd->genpd;
>> +
>> +               scmi_pd->domain = i;
>> +               scmi_pd->handle = handle;
>> +               scmi_pd->name = handle->power_ops->name_get(handle, i);
>> +               scmi_pd->genpd.name = scmi_pd->name;
>> +               scmi_pd->genpd.power_off = scmi_pd_power_off;
>> +               scmi_pd->genpd.power_on = scmi_pd_power_on;
>> +
>> +               /*
>> +                * Treat all power domains as off at boot.
>> +                *
>> +                * The SCP firmware itself may have switched on some domains,
>> +                * but for reference counting purpose, keep it this way.
>> +                */
> 
> I think it would be better to give the correct information about the
> state of the PM domain. Otherwise genpd may end up thinking a PM
> domain is off, while in fact it's on - thus wasting power.
> 

Agreed, I missed to notice that. I will fixup and send the update.

-- 
Regards,
Sudeep