On Thu, Feb 05, 2015 at 11:40:40PM +0000, Russell King - ARM Linux wrote: > On Thu, Feb 05, 2015 at 08:09:22PM +0100, Wolfram Sang wrote: > > clk_get functions return an ERR_PTR and not NULL in the error case. Make > > that consistent for the dummy functions when HAVE_CLK is not enabled. > > Otherwise unexpected codepaths might be trying to use a NULL pointer. > > NAK. > > There are some drivers which rely on this behaviour (take a driver, > such as some PXA IP) which uses the clk API but is also reused on > x86 which doesn't.
Okay, thanks for the explanation. Let me recap, there are three cases that clk_get can return: a) pointer to a clk b) ERR_PTR meaning something went wrong when trying to get a clk c) NULL meaning there is no clk to get So, if this patch from i2c/for-next [1] wants to add optional clk support, it should fallback to the old handling not by checking for (!IS_ERR()) but for (!IS_ERR_OR_NULL()). Correct? [1] https://git.kernel.org/cgit/linux/kernel/git/wsa/linux.git/commit/?h=i2c/for-next&id=e961a094afe04c6c8ca1adac50c8d16513f31b93
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