MikeDJohnson
Posts: 2
Joined: Mon Feb 20, 2017 8:48 am

using bcm2835-smi-dev on CM3

Mon Feb 20, 2017 8:59 am

Hi,
Looking at interfacing the CM3 to an FPGA using the SMI. As usual with BCM, limited documentation is a problem.

The bcm2835-smi-dev looks like a good starting point, and I can load the device tree overlay and see the kernel module is loaded with lsmod.

Looking at the driver code, it should register the device, however I don't see anything in /dev.
The bcm2835-gpiomem driver looks very similar in the registration, and we get a /dev/bcm2835-gpiomem

I didn't think mknod was needed nowadays?

Any pointers would be appreciated - especially an app snippit which opens any of the SMI drivers :)

I'm currently basing the hardware directly with /dev/mem which is fine, but I would want to modify or use a kernel driver eventually.

Many thanks,
Mike


MikeDJohnson
Posts: 2
Joined: Mon Feb 20, 2017 8:48 am

Re: using bcm2835-smi-dev on CM3

Fri Aug 25, 2017 9:36 am

Thanks (I just saw your reply). I have the driver, but no additional documentation is available yet?
I am designing the hardware on the other side of the interface, and modifying the timing without any register details is a pain.

Best,
Mike

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1210
Joined: Sat Sep 10, 2011 11:43 am

Re: using bcm2835-smi-dev on CM3

Fri Aug 25, 2017 9:43 am

Luke wrote the include file to cover the documentation...

https://github.com/raspberrypi/linux/bl ... 2835_smi.h

That contains all the information concerning the register definitions when it comes to timing, there isn't much else otherwise.

Gordon
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

Return to “Compute Module”

Who is online

Users browsing this forum: No registered users and 3 guests