of_clk_add_(hw_)providers multipule times for one node?

Masahiro Yamada
2016-07-08T17:23:54Z

Hi.

I think the current code allows to add
clk_providers multiple times against one DT node.

Are there cases that really need to do so?

I am thinking the behavior of __of_clk_get_from_provider() is strange.

The result of __of_clk_get_from_provider() has three patterns:

[1] success
[2] return -EPROBE_DEFER
[3] return -EINVAL (if clkspec == NULL)

[3] is a rare case.
So, almost all error cases are treated as -EPROBE_DEFER.

A strange scenario
------------------

If a too big clock index is passed in clkspec,
of_clk_src_onecell_get() returns -EINVAL. This is reasonable.

But, __of_clk_get_from_provider() tries to search next nodes despite
that it has already failed to get a clk.

Then, it reaches the end of list_for_each_entry() loop, and returns
-EPROBE_DEFER. This is not deferred probe at all! In this case,
__of_clk_get_from_provider() should return -EINVAL.

If this is a bug, I am happy to volunteer to fix it.

Thanks.

--
Best Regards
Masahiro Yamada