On Wed, 2013-01-02 at 08:10 +0300, Dan Carpenter wrote: > clk_get() returns NULL if CONFIG_HAVE_CLK is disabled. > > I told Tony about this but everyone has been gone with end of year > holidays so it hasn't been addressed. > > Tony, please fix it so people don't apply these patches until > clk_get() is updated to not return NULL. It sucks to have to revert > patches. > > regards, > dan carpenter I posted the query to Mike Turquette, linux-kernel and linux-arm-kernel mailing lists, regarding the return of NULL when HAVE_CLK is undefined. Short Answer: A return value of NULL is valid and not an error therefore we should be using IS_ERR, not IS_ERR_OR_NULL on clk_get results. I see the obvious problem this creates, and asked this question: If the driver can't operate with a NULL clk, it should use a IS_ERR_OR_NULL test to test for failure, rather than IS_ERR. And Russell's answer: Why should a _consumer_ of a clock care? It is _very_ important that people get this idea - to a consumer, the struct clk is just an opaque cookie. The fact that it appears to be a pointer does _not_ mean that the driver can do any kind of dereferencing on that pointer - it should never do so. Thread can be viewed here: https://lkml.org/lkml/2012/12/20/105 Regards Tony Prisk -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
