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SubjectRe: [alsa-devel] [Patch v6 1/7] slimbus: Device management on SLIMbus
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On 11/10/17 05:07, Vinod Koul wrote:
> On Tue, Oct 10, 2017 at 06:21:34PM +0100, Srinivas Kandagatla wrote:
>> On 10/10/17 17:49, Vinod Koul wrote:
>
>>>>>> +static int slim_device_probe(struct device *dev)
>>>>>> +{
>>>>>> + struct slim_device *sbdev;
>>>>>> + struct slim_driver *sbdrv;
>>>>>> + int status = 0;
>>>>>> +
>>>>>> + sbdev = to_slim_device(dev);
>>>>>> + sbdrv = to_slim_driver(dev->driver);
>>>>>> +
>>>>>> + sbdev->driver = sbdrv;
>>>>>> +
>>>>>> + if (sbdrv->probe)
>>>>>> + status = sbdrv->probe(sbdev);
>>>>>> +
>>>>>> + if (status)
>>>>>> + sbdev->driver = NULL;
>>>>>> + else if (sbdrv->device_up)
>>>>>> + schedule_slim_report(sbdev->ctrl, sbdev, true);
>>>>>
>>>>> can you please explain what this is trying to do?
>>>>
>>>> It is scheduling a device_up() callback in workqueue for reporting
>>>> discovered device.
>>>
>>> any reason for that? Would the device not announce itself on the bus and
>>> then you can synchronously update the device.
>> You are correct, Device should announce itself in all cases. core should
>> only call this callback only when device is announced, it does not make
>> sense for this call in slim_device_probe(). Will remove it from here in next
>> version.
>
> Okay great. Btw do you need a notify being scheduled in those cases? I guess
> your controller would get an interrupt and you will handle that in bottom
> half and then cll this, so why not call in the bottom half?
>
That makes sense, I will optimize this path, It looks like there are 2
workqueues in this path. We should be able to get rid of one work-queue.



>>>>>> +/**
>>>>>> + * slim_register_controller: Controller bring-up and registration.
>> ...
>>>>>> +
>>>>>> + mutex_init(&ctrl->m_ctrl);
>>>>>> + ret = device_register(&ctrl->dev);
>>>>>
>>>>> one more device_register?? Can you explain why
>>>>>
>>>>
>>>> This is a device for each controller.
>>>
>>> wont the controller have its own platform_device?
>>
>> Reason could be that slim_register controller can be called from any code
>> not just platform devices..
>
> ah which cases would those be. I was expecting that you would have a
> platform_device as a slimbus controller which would call slim_register?
As of now there is only one controller which uses platform driver, but
in future there might be more, but this is something which makes the
slimbus core more flexible.


>

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