Re: PMBus support in Linux

[Guenter Roeck <guenter.roeck-IzeFyvvaP7pWk0Htik3J/w@public.gmane.org>]

On Sun, May 30, 2010 at 12:15:07AM -0400, Wolfram Sang wrote:
> > > So, the approach I see (unless I miss something) would be writing an
> > > hwmon-I2C-driver named pmbus-devices.c or so which covers the generic
> > > functionality and provides some hooks for manufacturer extensions, if those are
> > > necessary? (Altough I'd hope a number of devices would be covered by the
> > > generic driver) Makes sense?
> > > 
> > That would be one option. It would require either a register() API call, or a table
> > of supported chips, or a combination of both, to identify how many channels
> > (or pages, in PMBus terminology) per chip are supported and to identify supported
> > objects/registers.
> 
> I am missing the details here, i.e. what data is needed to describe a device
> and is the data static or can it be retrieved/updated at runtime. A decision
> between tables[] or register() or both depends probably on that.
> 
It _may_ be possible to detect the supported commands (ie sensors per page/phase)
reliably using the QUERY command, but I do not feel comfortable doing the same
to determine the number of pages and phases supported.

I'll have to see once I get my hands on actual HW what can be detected reliably 
and what has to be configured.

Guenter