[U-Boot] [PATCH 1/8] core: Add uclass_{first, next}_device_compat

[Mario Six]

Hi Simon,

On Thu, Apr 12, 2018 at 6:31 PM, Simon Glass <sjg at chromium.org> wrote:
> Hi Mario,
>
> On 11 April 2018 at 01:15, Mario Six <mario.six at gdsys.cc> wrote:
>> Hi Simon,
>>
>> On Fri, Mar 30, 2018 at 10:41 AM, Simon Glass <sjg at chromium.org> wrote:
>>> Hi Mario,
>>>
>>> On 28 March 2018 at 20:38, Mario Six <mario.six at gdsys.cc> wrote:
>>>> A lot of times one wants to cycle through the devices in a uclass, but
>>>> only certain ones, especially ones identified by their compatibility
>>>> string, and ignore all others (in the best case this procedure should
>>>> not even activate the devices one is not interested in).
>>>>
>>>> Hence, we add a pair of functions similar to uclass_{first,next}_device,
>>>> but taking a compatibility string as an additional argument, which cycle
>>>> through the devices of a uclass that conform to this compatibility
>>>> string.
>>>
>>> Can we not use a phandle to find the device? Using raw compatible
>>> strings feel bad (and slow to me).
>>>
>>> If not, a please add a sandbox test.
>>>
>>
>> A phandle would indeed be the cleaner solution, but it won't work if you have
>> to get device handles in board files, since there is no device for a board you
>> could query for a phandle. And the MPC83xx board this series leads up to needs
>> to gather numerous device handles for configuration and querying purposes.
>>
>> If there was a underlying device for the board functions there would be no
>> issue with using a phandle, but as it is, it sadly won't work.
>
> Yes, actually this comes up a lot. Perhaps we should support a 'board'
> device which can have phandles pointing to things? It would be easy to
> implement. I'm not sure how Linux handles this stuff?
>

I'll see what I can do. And, well, the whole concept of a "board" doesn't
really exist in Linux the way it does in U-Boot, but from what I can tell, the
drivers in drivers/platfrom seem to be kind of similar to that.

> Regards,
> Simon
>

Best regards,
Mario