[PATCH v2] USB: ohci-at91: add usb_clk for transition to common clk framework

[Alan Stern]

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).
> 
> Changes since v1:
>  - use IS_ENABLED(CONFIG_COMMON_CLK) to isolate new at91 clk support
> 
> Signed-off-by: Boris BREZILLON <b.brezillon at overkiz.com>

Acked-by: Alan Stern <stern at rowland.harvard.edu>