FreeBSD 12.0 RBPI3B+ and hardware clock support

[Ian Lepore]

On Wed, 2018-11-21 at 22:30 +0200, Stefan Parvu wrote:
> > 
> > We have support for most major/popular i2c-based realtimeclock
> > chips.
> Right now we have a system based on MCP79410 [1] - It would be sweet
> to
> get this running on 12.0 - Any pointers: is this chip supported ?
> 
> Thanks,
> Stefan
> 
> [1] https://www.microchip.com/wwwproducts/en/MCP79410
> <https://www.microchip.com/wwwproducts/en/MCP79410> 

Oddly enough, the ds1307 driver supports that chip. I think it's
because the register set on the two chips is identical (or close enough
to work right).

In the DTS overlay when defining that i2c slave device, use a
compatible string of "microchip,mcp7941x" and the ds1307 driver will
attach. The ds1307(4) manpage doesn't mention the MCP support, but
everything else in that manpage should apply.

-- Ian