On Mon, 2017-04-03 at 14:33 +0000, Shevchenko, Andriy wrote: > On Mon, 2017-04-03 at 17:31 +0300, Andy Shevchenko wrote: > > On Mon, 2017-04-03 at 16:27 +0200, Philipp Zabel wrote: > > > > > > > > int rstc_id; > > > > int ret; > > > > > > > > - if (!node) > > > > - return ERR_PTR(-EINVAL); > > > > - > > > > > > This should be > > > > > > if (!node) > > > return optional ? NULL : ERR_PTR(-EINVAL); > > > > > > instead. Can you confirm this works for Intel boards with DW UART? I > > > can > > > fix it up when applying if you agree. > > > > I don't think it worth to change. I specifically checked all of_* > > calls > > in that function and they cope pretty nice with node == NULL.
__of_reset_control_get called with id != NULL calls of_property_match_string first, which then returns -EINVAL if node == NULL, which makes __of_reset_control_get return NULL if optional or -ENOENT otherwise, even though the correct return value would be -EINVAL in the DT case. __of_reset_control_get called with id == NULL calls of_parse_phandle_with_args first, which calls __of_parse_phandle_with_args, which returns an undefined value if np == NULL, as far as I can tell: of_for_each_phandle first calls of_phandle_iterator_init, which, when called with np == NULL clears the iterator structure returns -ENOENT. The return value is ignored in the of_for_each_phandle macro, and of_phandle_iterator_next is then called and returns -ENOENT because it->cur == NULL, ending the loop without ever assigning a value to rc. __of_parse_phandle_with_args then returns the uninitialized value. The point being, instead of having to regularly forage through a number of of_ API functions to make sure my expectations are still met, I'd prefer to keep the check in place. > > > > So, I rather to go with my initial change. > > > > Hit Enter before closing another thought. > > When you come with solution where this __of_reset_control_get() will be > called only for node != NULL case you will not need that check either. __of_reset_control_get is public API (via of_reset_control_get), so I can't guarantee node != NULL even in the DT case. > So, I would go my solution because of two benefits: > - it fixes bug True. > - if will not bring ping-ponging code Unfortunately not. regards Philipp
