Re: [PATCH 3/3] firmware: scpi: add device power domain support using genpd

From: Sudeep Holla <sudeep.holla@arm.com>
To: "Jon Medhurst (Tixy)" <tixy@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
	linux-kernel@vger.kernel.org,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Kevin Hilman <khilman@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	linux-pm@vger.kernel.org
Subject: Re: [PATCH 3/3] firmware: scpi: add device power domain support using genpd
Date: Tue, 7 Jun 2016 14:29:44 +0100	[thread overview]
Message-ID: <5756CC48.8050001@arm.com> (raw)
In-Reply-To: <1465305537.2833.28.camel@linaro.org>

On 07/06/16 14:18, Jon Medhurst (Tixy) wrote:
> On Mon, 2016-06-06 at 16:53 +0100, Sudeep Holla wrote:
>> This patch hooks up the support for device power domain provided by
>> SCPI using the Linux generic power domain infrastructure.
>>
>> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
>> Cc: Kevin Hilman <khilman@kernel.org>
>> Cc: Ulf Hansson <ulf.hansson@linaro.org>
>> Cc: linux-pm@vger.kernel.org
>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
>> ---
>>   drivers/firmware/Kconfig   |   8 +++
>>   drivers/firmware/Makefile  |   1 +
>>   drivers/firmware/scpi_pd.c | 152 +++++++++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 161 insertions(+)
>>   create mode 100644 drivers/firmware/scpi_pd.c
>>
>> Hi,
>>
>> Since most of the power controller drivers are place in drivers/soc/<soc_name>,
>> I am not sure where to put this SCPI power domain code as it can be used
>> on multiple SoC. I have placed it in drivers/firmware temporarily for
>> review. Please suggest the most apt place to put this driver.
>>
>> Regards,
>> Sudeep
>>
>> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
>> index 41abdc54815e..80c963c60f13 100644
>> --- a/drivers/firmware/Kconfig
>> +++ b/drivers/firmware/Kconfig
>> @@ -27,6 +27,14 @@ config ARM_SCPI_PROTOCOL
>>   	  This protocol library provides interface for all the client drivers
>>   	  making use of the features offered by the SCP.
>>
>> +config ARM_SCPI_POWER_DOMAIN
>> +	tristate "SCPI power domain driver"
>> +	depends on (ARM_SCPI_PROTOCOL && PM) || COMPILE_TEST
>> +	select PM_GENERIC_DOMAINS_OF
>

Actually I had something like below before and changed it before posting.

config ARM_SCPI_POWER_DOMAIN
	tristate "SCPI power domain driver"
	depends on ARM_SCPI_PROTOCOL || COMPILE_TEST
	select PM_GENERIC_DOMAINS if PM
	select PM_GENERIC_DOMAINS_OF if PM

The idea was to allow compilation of this even if PM was disabled.

> That select doesn't work for me and gives:
>
> warning: (ARM_SCPI_POWER_DOMAIN) selects PM_GENERIC_DOMAINS_OF which has unmet direct dependencies (PM_GENERIC_DOMAINS && OF)
>
> Followed by link errors due to missing symbols.
>
> I think you need to select PM_GENERIC_DOMAINS as well.

I agree, that's exactly what I had before.

> Or perhaps just instead of, as PM_GENERIC_DOMAINS_OF defaults 'y' and isn't user
> selectable. From kernel/power/Kconfig ...
>

Makes sense, I am fine with that too.

-- 
Regards,
Sudeep