I2C and CAN bus on MPC5200B device tree
Wolfgang Grandegger
wg at grandegger.com
Mon Jan 14 19:10:01 EST 2008
Grant Likely wrote:
> On 1/13/08, Matt Sealey <matt at genesi-usa.com> wrote:
>> Hi guys,
>>
>> I know the I2C stuff is up in the air (I cannot pinpoint the documentation
>> for it) and have not found any CAN bus documentation for device trees.
>>
>> I want to update the firmware tree to add these but, am basically looking
>> for those docs, or someone to go over a few points.. is there some kind of
>> tree standard I should be looking at, or some patch I missed which has
>> a driver which implements something that looks at a compatible tree?
>
> I think some consensus has been achieved for describing i2c busses and
> their attached devices, but I don't think booting-without-of.txt has
> been updated with the details yet. I need to look into that more.
>
> I don't think anyone has tackled CAN. Best bet is to draft a tree in
> the way you think it should be described and post it to the list.
> That will give a starting point for us to discuss it and come to
> consensus.
For MSCAN on the MPC5200 we currently have:
mscan at 900 {
device_type = "mscan";
compatible = "mpc5200b-mscan","mpc5200-mscan";
cell-index = <0>;
interrupts = <2 11 0>;
interrupt-parent = <&mpc5200_pic>;
reg = <900 80>;
};
mscan at 980 {
device_type = "mscan";
compatible = "mpc5200b-mscan","mpc5200-mscan";
cell-index = <1>;
interrupts = <2 12 0>;
interrupt-parent = <&mpc5200_pic>;
reg = <980 80>;
};
The only thing missing is a property defining the routing of the CAN
signals, CAN 1 on I2C1 pins or CAN 2 on TMR01 pins. I think it does not
make sense to describe CAN devices on the CAN bus like for I2C.
Wolfgang.
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