Re: [PATCH 1/3] ipmi/bt-bmc: change compatible node to 'aspeed, ast2400-ibt-bmc'

[Arnd Bergmann <arnd@arndb.de>]

On Wednesday, November 2, 2016 3:28:01 PM CET Cédric Le Goater wrote:
> On 11/02/2016 02:56 PM, Joel Stanley wrote:
> > On Wed, Nov 2, 2016 at 11:45 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> >> On Wednesday 02 November 2016, Cédric Le Goater wrote:
> >>> The Aspeed SoCs have two BT interfaces : one is IPMI compliant and the
> >>> other is H8S/2168 compliant.
> >>>
> >>> The current ipmi/bt-bmc driver implements the IPMI version and we
> >>> should reflect its nature in the compatible node name using
> >>> 'aspeed,ast2400-ibt-bmc' instead of 'aspeed,ast2400-bt-bmc'. The
> >>> latter should be used for a H8S interface driver if it is implemented
> >>> one day.
> >>>
> >>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> >>
> >> We generally try to avoid changing the compatible strings after the
> >> fact, but it's probably ok in this case.
> 
> As the device tree changes are not merged yet, we thought we had some 
> more time to fine tune the naming. 

Ok, I see. No problem then.

> >> I don't understand who decides which of the two interfaces is used:
> >> is it the same register set that can be driven by either one or the
> >> other driver, or do you expect to have two drivers that can both
> >> be active in the same system and talk to different hardware once
> >> you get there?
> > 
> > It's the second case. The H8S BT has a different register layout so it
> > would require a different driver.
> 
> yes.
>  
> > We don't yet have a driver for the other BT device, but there was
> > recent talk of using it as an alternate (non-ipmi channel) between the
> > BMC and the host. Before that discussion I wasn't aware that the H8S
> > BT existed. I suggested we fix this up before it hits a final release.
> > 
> > Cédric, do you think ast2400-ibt-bmc or ast2400-ipmi-bt-bmc does a
> > better job of describing the hardware here?
> 
> The specs refer to the two interfaces as BT (non IPMI) and iBT (IPMI). 
> I think we can keep the same naming.

Ok

> > While we're modifying the binding, should we add a compat string for
> > the ast2500?
> 
> Well, if the change in this patch is fine for all, may be we can add 
> the ast2500 compat string in a followup patch ?

Sounds good to me.

	Arnd

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