linux-kernel - Re: [PATCH v3] tpm: do not suspend/resume if power stays on

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Date:   Tue, 7 Mar 2017 09:44:55 +0100
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     Rob Herring <robh+dt@...nel.org>, Peter Huewe <peterhuewe@....de>,
        Mark Rutland <mark.rutland@....com>,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        tpmdd-devel@...ts.sourceforge.net,
        Sonny Rao <sonnyrao@...omium.org>
Subject: Re: [PATCH v3] tpm: do not suspend/resume if power stays on

Hi Jarkko,

On 06/03/17 21:59, Jarkko Sakkinen wrote:
> On Fri, Mar 03, 2017 at 05:09:59PM +0100, Enric Balletbo i Serra wrote:
>> From: Sonny Rao <sonnyrao@...omium.org>
>>
>> The suspend/resume behavior of the TPM can be controlled by setting
>> "powered-while-suspended" in the DTS. This is useful for the cases
>> when hardware does not power-off the TPM.
>>
>> Signed-off-by: Sonny Rao <sonnyrao@...omium.org>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
>> ---
>> Changes since v2:
>>  Jarkko Sakkinen
>>   - Add a new TPM_CHIP_FLAG_ALWAYS_POWERED flag instead of using a boolean variable.
>>   - Remove a trailing newline.
>> Changes since v1:
>>  Jason Gunthorpe :
>>   - Move the code to handle suspend/resume in the common chip code.
>>
>>  Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt | 6 ++++++
>>  drivers/char/tpm/tpm-interface.c                           | 3 +++
>>  drivers/char/tpm/tpm.h                                     | 1 +
>>  drivers/char/tpm/tpm_of.c                                  | 3 +++
>>  4 files changed, 13 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt b/Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt
>> index 8cb638b..85c8216 100644
>> --- a/Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt
>> +++ b/Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt
>> @@ -8,6 +8,12 @@ Required properties:
>>                     the firmware event log
>>  - linux,sml-size : size of the memory allocated for the firmware event log
>>  
>> +Optional properties:
>> +
>> +- powered-while-suspended: present when the TPM is left powered on between
>> +                           suspend and resume (makes the suspend/resume
>> +                           callbacks do nothing).
>> +
>>  Example (for OpenPower Systems with Nuvoton TPM 2.0 on I2C)
>>  ----------------------------------------------------------
> 
> Hey, just noticed something. Shouldn't this be a separate commit?

During my life submitting patches I saw the both options, sometimes the maintainer asked me to join the DT patch and the driver and sometimes he asked me to do in different patches, so I think this is more a maintainer option. Maybe Rob Herring or Mark Rutland can share their preferences?

I'll do what you want I do, TBH I don't have a strong opinion about this.

> I'm also wondering whether this can be submitted through my tree
> upper maintainers.
> 
> Does not change my reviewed-by for the actual code change but you
> would have to split this into a patch set if this is the case.
> 
> /Jarkko
> 

Cheers,
 Enric