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

From: Sergei Shtylyov
Date: Thu Aug 01 2013 - 13:30:11 EST


On 08/01/2013 07:56 PM, Alan Stern 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

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

You probably meant IS_ENABLED() or IS_BUIILTIN()? Or is there something I don't know about gcc 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

WBR, Sergei

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