`uclass_find_device_by_name` fails to find the device

[Simon Glass]

HI Nandor,

On Wed, 6 Nov 2019 at 06:09, Nandor Han <nandor.han at vaisala.com> wrote:
>
> Hi everybody,
>    I've noticed that commit 4213609cc7fb78f84b2ea63f4a5691b60d01c248
> changes how `uclass.c:uclass_find_device_by_name` function compares the
> names for finding devices.
>
> Because of this I have an issue when having a DTS and trying to find a
> device by name.
>
> The `lists.c:lists_bind_fdt` function will bind a device to a device
> node tree and use the node name as device name.
>
> ```
> lists.c:
> int lists_bind_fdt(..)
> ...
> name = ofnode_get_name(node);
> ...
>
> ```
> Because of this devices will end up having names like: i2c at 021a0000,
> pfuze100 at 8...
>
> When using `uclass.c:uclass_find_device_by_name` to get a device, before
> the change, this was not an issue since `strncmp` was used with the
> length of the name making a call like
> `uclass_find_device_by_name(pfuze100)` successfully even if the device
> name was `pfuze100 at 8`.
> ```
> if (!strncmp(dev->name, name, strlen(name))) {
> ```
>
> However after the change (which I think is correct), the check fails,
> resulting in not finding the expected device, since the device name has
> also the suffix `@...` included.
>
> What's the proper fix here:
>
> 1. Changing the `lists.c:lists_bind_fdt` to drop the `@` suffix?
>      Note: Could this be a problem when having the same node names but
> different addressees in DTS {e.g.foo at 1, foo at 2}
>
> 2. When using `uclass.c:uclass_find_device_by_name` the user should take
> in consideration that `@..` suffix needs to be added.
>     Note: This could be a problem when same code is used with different
> DTSs.
>
> 3. Changing the comparation in `uclass.c:uclass_find_device_by_name` to
> ignore the part after `@` for device names.
>
> 4. What else?

Can you use a phandle to refer to the device from another node,
perhaps a UCLASS_BOARD node if needed? It is not a good idea to use
this function.

Alternatively we could add a new function which finds by partial name.

Regards,
Simon