Re: [PATCH v2] of: i2c: Add idle-disconnect DT property to PCA954x mux driver

[Alexander Sverdlin <alexander.sverdlin-OYasijW0DpE@public.gmane.org>]

Hi Wolfram,

On 15/01/15 14:19, ext Wolfram Sang wrote:
>>>> of: i2c: Add idle-disconnect DT property to PCA954x mux driver
>>>> > >>
>>>> > >> Add idle-disconnect device tree property to PCA954x mux driver. The new property
>>>> > >> forces the multiplexer to disconnect child buses in idle state. This is used, for
>>>> > >> example, when there are several multiplexers on the same bus and the devices on
>>>> > >> the underlying buses might have same I2C addresses.
>>> > > 
>>> > > Basically OK. Question to DT maintainers: "idle-disconnect",
>>> > > "i2c-mux-idle-disconnect", or is there another existing binding we could
>>> > > use?
>>> > > 
>>>> > >> At the same time old (and not used in the tree) platform data binding
>>>> > >> deselect_on_exit is removed to simplify the implementation. Old binding has
>>>> > >> different (per-channel) semantics and doesn't fit well in the new concept.
>>> > > 
>>> > > I'd prefer to keep it. It should be only one || more. It is not really
>>> > > in the way IMO.
>> > 
>> > It complicates the implementation 3x times :) This is part of our discussion with Laurent:
> Does it? I don't want DT and platform_data to behave equally. I just
> want to keep being backwards compatible. So, I'd suggest:
> 
> (pdata && pdata->modes[num].deselect_on_exit) || idle_disconnect ? pca954x_deselect_mux : NULL);

you are right, thanks for the hint :)
I'll prepare v3...

-- 
Best regards,
Alexander Sverdlin.