Re: [PATCH] USB: ohci-at91: add usb_clk for transition to commonclk framework

From: Alan Stern
Date: Thu Aug 01 2013 - 11:56:15 EST

On Thu, 1 Aug 2013, boris brezillon wrote:

> > What happens if uclk isn't found but it is needed?
> It will not fail but I guess the usb host won't work as the clock won't
> be correctly
> configured.
> I agree with you: this is not a good solution.
> Another option is to keep the previous version of this patch and put
> uclk handling
> in "#ifdef CONFIG_COMMON_CLK #endif" sections.
> Would this be acceptable ?

Yes. However, a more elegant approach is to protect the relevant
statements with: if (defined(CONFIG_COMMON_CLK)). This preprocessor
evaluates this to a 0 or 1, so the compiler will not generate output
for the protected source code if the symbol isn't defined.

Alan Stern

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