[U-Boot] [PATCH 1/3] core: Add function to get device for ofnode

[Mario Six]

Hi Simon,

On Sun, Apr 22, 2018 at 10:13 PM, Simon Glass <sjg at chromium.org> wrote:
> Hi Mario,
>
> On 18 April 2018 at 02:20, Mario Six <mario.six at gdsys.cc> wrote:
>> Hi Simon,
>>
>> On Thu, Apr 12, 2018 at 6:42 PM, Simon Glass <sjg at chromium.org> wrote:
>>> Hi Mario,
>>>
>>> On 10 April 2018 at 05:34, Mario Six <mario.six at gdsys.cc> wrote:
>>>> Hi Simon,
>>>>
>>>> On Fri, Mar 30, 2018 at 12:43 AM, Simon Glass <sjg at chromium.org> wrote:
>>>>> Hi Mario,
>>>>>
>>>>> On 28 March 2018 at 20:37, Mario Six <mario.six at gdsys.cc> wrote:
>>>>>> It's sometimes useful to get the device associated with a given
> ofnode.
>>>>>> Implement a function to implement this lookup operation.
>>>>>
>>>>> Where would you use this? Can you not use phandles to find the device?
>>>>> Or uclass_get_device_by_ofnode() ?
>>>>>
>>>>
>>>> The function is used with the dev_{enable,disable}_by_path in the next
> patch:
>>>> If I used any of the uclass_* functions or similar, the device would be
> probed,
>>>> which is not what I want, since the device may not actually be
> physically
>>>> present.
>>>
>>> So how about using uclass_find_device_by_ofnode() ?
>>>
>>
>> That would work for the disabling, true, but not for the enabling (which
> is
>> what is used in the upcoming board): Since the node is declared as
> disabled in
>> the DT, the device is not even bound (so uclass_find_device_by_ofnode)
> won't
>> return it.
>>
>> A more elegant solution would be to have device_probe check again if the
>> underlying ofnode is disabled, and stop the probing if that's the case.
> In this
>> scenario the disabled devices would still be displayed in the tree, but
> never
>> probed, which is probably OK (I don't know if there would be any side
> effects
>> with iterating through devices, for example). But changing the behavior
> of such
>> elementary API functions is probably not a good idea.
>
> That seems to be a different topic.
>
> Fundamentally I don't see the difference between
> uclass_find_device_by_ofnode() and your ofnode_dev().
>
> If you want to enable something after probing you will have to call
> device_bind() or similar. If that is your intent, I think you need a
> different function from ofnode_dev(), since it also relies on the device
> already being bound.
>

Ah, yes, I forgot that the *find* functions don't probe, sorry about that.

Yes, right, it won't be a problem to use uclass_find_device_by_ofnode
instead then.

> Regards,
> Simon
>

Best regards,
Mario