On Fri, Mar 21, 2008 at 7:00 AM, Sergei Shtylyov <[EMAIL PROTECTED]> wrote: > Grant Likely wrote: > > Personally, I'm not fond of this approach. There is already some > > traction to using the reg-shift property to specify spacing, and I > > think it would be appropriate to also define a reg-offset property to > > handle the +3 offset and then let the xilinx 16550 nodes use those. > > That's making things only worse than the mere "reg-shift" idea. I think > that both are totally wrong. Everything about the programming interface > should > be said in the "compatible" and possibly "model" properties. of_serial driver > should recognize them and pass the necessary details to 8250.c. As for me, > I'm > strongly against plaguing the device tree with the *Linux driver > implementation specifics* (despite I was trying this with MTD -- there it > seemed somewhat more grounded :-).
Not true. Compatible defines what the node is describing. It is perfectly valid for a compatible value definition to also defines some additional properties that can be queried for interface details. Xilinx is completely free to define a "xlnx,..." compatible value for their ns16550 compatible device. However, 'sparse' ns16550 devices are a common and well known variation so I think it is valid and reasonable to define a compatible binding for this case. As for using a new binding like "sparse16550" instead of extending "ns16550"; it is because reg-shift and reg-offset would be required nodes and therefore is not compatible with drivers using the original ns16550 binding. Using a new namespace gives freedom to define the required properties. Cheers, g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
