[PATCH v3 6/7] USB: ohci-at91: add usb_clk for transition to common clk framework

[Alan Stern]

On Tue, 16 Jul 2013, boris brezillon wrote:

> >> +	uclk = clk_get(&pdev->dev, "usb_clk");
> >> +	if (IS_ERR(uclk)) {
> >> +		uclk = NULL;
> >> +		dev_warn(&pdev->dev, "failed to get usb_clk\n");
> >> +	}
> > Is this really what you want for backward compatibility?
> Here are some proposition to remove the warning message:
> 
> 1) replace it with a dev_info and change the message:
>      dev_info(&pdev->dev, "failed to get usb_clk (most likely using old 
> at91 clk implementation)\n");
> 2) drop the log and silently ignore the missing clk (I'm not a big fan 
> of this solution
>      as it may lead to some errors if we're using new clk implem and the 
> clock is really missing)
> 3) rework the current clk_set_rate function to accept clk_set_rate on 
> usb clk and add clk_lookup entries
>      for the usb clk (I'm not a big fan of this solution neither as this 
> modifications will only be used for a short time
>      until the transition to common clk framework is completed).

Another possibility is to combine this change with the clock 
implementation update, and do them in a single patch.  Then backward 
compatibility would not be an issue.

Alan Stern