Re: [PATCH v2 3/3] can: sja1000: of: add compatibility with Technologic Systems version

From: Damien Riegel
Date: Tue Jan 12 2016 - 10:51:30 EST

On Tue, Jan 12, 2016 at 08:55:38AM +0100, Marc Kleine-Budde wrote:
> On 12/24/2015 06:42 PM, Damien Riegel wrote:
> > Technologic Systems provides an IP compatible with the SJA1000,
> > instantiated in an FPGA. Because of some bus widths issue, access to
> > registers is made through a "window" that works like this:
> >
> > base + 0x0: address to read/write
> > base + 0x2: 8-bit register value
> Why do you use io{read,write}16 if it's a 8 bit register?

8-bit is at the IP level, but the bus between the SoC and the FPGA only
supports 16-bit wide access. The point of the window is to convert
between 16-bit and 8-bit access.