[U-Boot] [PATCH v3] usb: new board-specific USB init interface

Marek Vasut
2013-09-06T11:40:32Z

Dear Mateusz Zalega,

> On 09/06/13 13:24, Marek Vasut wrote:
> >>>>> Moreover, the 'int index' should likely be unsigned int and the
> >>>>> special value to init all controllers at once should probably then
> >>>>> be 0xffffffff
> >>>>
> >>>> Despite our greatest ambitions, I don't think we're likely to use more
> >>>> than 2^31-1 USB controllers at a time. Besides, negative values look
> >>>> better both in code and debugger session.
> >>>
> >>> Thinking of it further, instead of using negative value here, like I
> >>> mentioned above, why not make the "board_usb_init_type" into a field of
> >>> flags , then add flag to init all controllers at once ?
> >>
> >> That's unnecessary. It wouldn't lead to any practical advantage over
> >> existing interface.
> >
> > The advantage would be you won't be mixing two things (value AND value
> > with special meaning) into the "index" parameter.
>
> Alright, provide a use-case. The only 'special' value we have now
> doesn't interfere with controller index. Why write code or interfaces
> that won't ever be used?

Look, abusing the index field with a special value is moronic, especially if you
_do_ have another field that can very well be turned into a block of flags
instead of enum right next to it.

function(int foo , enum bar)
| ^
| |
`---------'
flags go
here

Then int foo can be turned into unsigned int foo _and_ be used for it's one
singular purpose. Likewise, enum bar will now be "unsigned int flags" . Do you
see the separation now ?

Best regards,
Marek Vasut