Hi Michael,
On 11/14/2013 02:53 PM, Michael Grzeschik wrote:
Hi Fabio,
On Thu, Nov 14, 2013 at 02:12:25PM -0200, Fabio Estevam wrote:
When using an external USB hub, it is common that they require a clock input.
Add a 'clk_usb' clock, so that it can be retrieved from the device tree and
enabled in the driver, so that the clock can properly drive the external
USB hub.
Tested on a imx6q-udoo board, that connects via USBH1 to a USB2514 hub.
In this board the USB2514 is clocked from a 24MHz clock that comes from the
imx6q CLKO2 pin.
what kind of hub is this? Why does it need an extra clock line? Usually
only a phy needs an extra clock line.
Here is the USB hub chip that mx6q udoo board uses:
http://ww1.microchip.com/downloads/en/DeviceDoc/251xb.pdf
(Search for "external 24MHz clock")
Regards,
Fabio Estevam
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