[PATCH] dm: make uclass_find_first_device() return error when no defice is found

[Masahiro Yamada]

Hi Simon,

On Thu, Feb 27, 2020 at 12:33 AM Simon Glass <sjg at chromium.org> wrote:
>
> Hi Masahiro,
>
> On Mon, 24 Feb 2020 at 23:58, Masahiro Yamada
> <yamada.masahiro at socionext.com> wrote:
> >
> > uclass_find_first_device() succeeds even if it cannot find any device.
> > So, the caller must check the return code and also *devp is not NULL.
> >
> > Returning -ENODEV will be sensible in this case.
> >
> > Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
> > ---
> >
> > If this patch is acceptable, I want to fold this
> > into my pull request because it need it
> > for my another patch:
> > http://patchwork.ozlabs.org/patch/1238000/
> >
> >  drivers/core/uclass.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
>
> I sort-of agree and have thought about this a lot.
>
> But what are you doing in the case of uclass_find_next_device()?
>
> Also what about the tests and other code that expects the current behaviour?


OK, I will change my caller side.



I would probably design these functions as follows:

struct udevice *uclass_find_first_device(enum uclass_id id);

struct udevice *uclass_find_next_device(struct udevice *dev);


Return the pointer to the device, or NULL if not found.









> >
> > diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
> > index 58b19a421091..3580974f3b85 100644
> > --- a/drivers/core/uclass.c
> > +++ b/drivers/core/uclass.c
> > @@ -227,7 +227,7 @@ int uclass_find_first_device(enum uclass_id id, struct udevice **devp)
> >         if (ret)
> >                 return ret;
> >         if (list_empty(&uc->dev_head))
> > -               return 0;
> > +               return -ENODEV;
> >
> >         *devp = list_first_entry(&uc->dev_head, struct udevice, uclass_node);
> >
> > --
> > 2.17.1
> >
>
> Regards,
> Simon



--
Best Regards
Masahiro Yamada