Re: [PATCH] rtc-ds1307: True SMBus compatibility

["Ed Swierk" <eswierk-BGArkANP9klv6pq1l3V1OdBPR1lH4CV8@public.gmane.org>]

On Wed, Jan 7, 2009 at 5:24 AM, Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org> wrote:
> Are you certain the nForce2 controllers can't do it? The i2c-nforce2
> driver doesn't implement it, but this doesn't mean the hardware can't
> do it. I don't have any datasheet for these chips, but I know their
> SMBus implementation is very similar to those of the AMD 8111, and
> i2c-amd8111 has support for I2C block reads and writes. I think it
> would be worth giving it a try, by copying the i2c-amd8111
> implementation into the i2c-nforce2 driver and seeing if it happens to
> just work. If it works, that would be more elegant than your proposed
> hack to the rtc-ds1307 driver.

I checked the datasheet and also tried every possible SMBus command
value to try to discover any supported commands that the i2c-nforce2
driver happens not to use, to no avail. The nVidia SMBus is pure
SMBus.

I could change the ds1307 driver to check whether the controller
supports i2c block commands and fall back to emulation only if they
are not available. Would that address your concerns?

--Ed