On Nov 4, 2011 11:08 PM, "Pavan Kondeti" [off-list ref] wrote:

Hi

On 11/4/2011 11:42 PM, Grant Likely wrote:

quoted

It is not legal for two device nodes to have overlapping 'reg' regions
(unless one is a child of the other), so by extension it is not okay
for two nodes to have the same 'name@addr'.  However, it is perfectly
acceptable and encouraged for two nodes at different addresses to
start with the same value for 'name@'.  This is called the generic
names recommended practice, and it can also be found in the ePAPR
documentation on node names.

If you want to have both host and device drivers bound to a single
device for OTG mode, then you should use a wrapper driver in Linux
that binds to the single node and instantiates each of the interfaces
as a child device.  For an example take a look at
drivers/usb/host/fsl-mph-dr-of.c.

Currently we have two platform devices one for OTG and one for host,
corresponding drivers for them. If I would like to keep it this way, the
device tree becomes something like below

hsusb0-otg: usb-otg@0xa6000000 {
       compatible = "qcom,hsusb-otg";
       ---
};

hsusb0-device: usb-gadget@0xa6000000 {
       compatible = "qcom,hsusb-device";
       ---
};

hsusb0-host: usb@0xa6000000 {
       compatible = "qcom,hsusb-host", "usb-ehci";
       ---
};

No, you don't need three nodes. Only one node for the whole thing since
from the hardware perspective it is still a single device. The driver for
that node should create the child otg and gadget platform_devices so that
you can preserve the existing driver structure.

There does not need to be a device tree node for every struct device in the
kernel.

g.

Are you okay with above naming convention?

--
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The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.