Re: [PATCH] i2c: s3c2410: Don't enable PM runtime on the adapter device

[Charles Keepax <ckeepax-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>]

On Thu, Apr 16, 2015 at 12:39:43PM +0200, Lars-Peter Clausen wrote:
> On 04/16/2015 12:33 PM, Sylwester Nawrocki wrote:
>> On 16/04/15 12:10, Charles Keepax wrote:
>>> Commit 523c5b89640e ("i2c: Remove support for legacy PM") removed the PM
>>> ops from the bus type, which causes the pm operations on the s3c2410
>>> adapter device to fail (-ENOSUPP in rpm_callback). The adapter device
>>> doesn't get bound to a driver and as such can't have its own pm_runtime
>>> callbacks. Previously this was fine as the bus callbacks would have been
>>> used, but now this can cause devices which use PM runtime and are
>>> attached over I2C to fail to resume.
>>>
>>> This commit fixes this issue by just doing the PM operations directly on
>>> the I2C device, rather than the adapter device in the driver and adding
>>> some stub callbacks for runtime suspend and resume.
>>>
>>> Signed-off-by: Charles Keepax <ckeepax-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>
>>> ---
>>>   drivers/i2c/busses/i2c-s3c2410.c |   21 ++++++++++++++++-----
>>>   1 files changed, 16 insertions(+), 5 deletions(-)
>>
>>> @@ -1253,7 +1253,6 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
>>>   	platform_set_drvdata(pdev, i2c);
>>>
>>
>> Wouldn't adding
>>
>> 	pm_runtime_no_callbacks(&pdev->dev);
>>
>> here let us avoid the runtime resume/suspend stubs?
>
> Or just do pm_runtime_no_callbacks on the adapter device. Preferably in 
> the I2C core. That should solve the issue without requiring any other 
> changes.
>
> - Lars

Ooops... missed that function, yeah that looks like a much better
option.

Thanks,
Charles