enable mcp2515 CAN controller module plus the corrresponding overlay

[msperl]

added mcp251x module to list of modules to get compiled as well as the c...orresponding overlay

Overlay gets loaded like this in /boot/config.txt:

dtoverlay=mcp2515-can0-overlay,oscillator=16000000,interrupt=25

(remember to enable the spi device)

[notro]

This will be welcomed by a lot of users.
The massive CAN controller forum thread is filled with people asking how to build these modules.

(remember to enable the spi device)

What do you mean?

[msperl]

I meant: add the following as well to /boot/config.txt:

dtparam=spi=on

[msperl]

Actually some of this should go into some documentation of the available overlays, but there is none...

[notro]

dtparam=spi=on

This just enables spi0.
The same thing you do in your overlay with: status = "okay";
Ref: https://github.com/raspberrypi/linux/blob/rpi-3.18.y/arch/arm/boot/dts/bcm2708-rpi-b-plus.dts#L103

Actually some of this should go into some documentation of the available overlays, but there is none...

Phil has done lots of documentation. See /boot/overlays/README
Don't remember where the source of that recides. I have made some overlays that I haven't documented yet...

[pelwell]

The canonical source for the README is in the firmware repo, under the boot directory, although I'm starting to think that perhaps the overlay sources and the README should all move elsewhere.

[notro]

although I'm starting to think that perhaps the overlay sources [..] should all move elsewhere

This has crossed my mind as well.

[msperl]

We could also just keep that in the wiki...
Or we put it in Documentation/devicetree/overlays

But I think that is a different discussion - so I created issue #869 to track that