2016-08-05 5:57 GMT+09:00 Stephen Boyd <sb...@codeaurora.org>: > On 07/19, Masahiro Yamada wrote: >> The .get(_hw) callback of an OF clock provider can return a NULL >> pointer in some cases. >> >> For example, of_clk_src_onecell_get() returns NULL for index 1 of a >> sparse array of clocks like follows: >> >> clk_num == 3 >> idx 0: UART clk >> idx 1: NULL (no clk is allocated) >> idx 2: I2C clk >> >> In such cases, clk_get() successfully returns NULL. >> >> A problem is that most drivers only check IS_ERR(), like follows: >> >> clk = devm_clk_get(dev, NULL); >> if (IS_ERR(clk)) >> return PTR_ERR(clk); >> >> It carries on moving forward and will probably be hit by a different >> error check with a different error message. > > NULL is a valid clk pointer, so we can't really do anything here > besides rely on driver authors to do the right thing.
I still do not understand this. I think clk_get() should return > 0 pointer on success, error-pointer on failure. I have no idea when NULL is useful as a return value of clk_get(). -- Best Regards Masahiro Yamada
