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

From: Alan Stern
Date: Thu Aug 01 2013 - 10:39:46 EST

On Thu, 1 Aug 2013, Boris BREZILLON wrote:

> The AT91 PMC (Power Management Controller) provides an USB clock used by
> USB Full Speed host (ohci) and USB Full Speed device (udc).
> The usb drivers (ohci and udc) must configure this clock to 48Mhz.
> This configuration was formely done in mach-at91/clock.c, but this
> implementation will be removed when moving to common clk framework.
> This patch adds support for usb clock retrieval and configuration, and is
> backward compatible with the current at91 clk implementation (if usb clk
> is not found, it does not configure/enable it).
> Signed-off-by: Boris BREZILLON <b.brezillon@xxxxxxxxxxx>

> @@ -163,6 +169,8 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
> goto err5;
> }
> + uclk = clk_get(&pdev->dev, "usb_clk");

What happens if uclk isn't found but it is needed?

Alan Stern

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