Re: [PATCH v5 7/8] media: i2c: add DS90UB913 driver

Laurent Pinchart
2023-01-04T13:56:04Z

Hi Tomi,

On Mon, Dec 26, 2022 at 09:25:34PM +0200, Tomi Valkeinen wrote:
> On 26/12/2022 18:56, Laurent Pinchart wrote:
> > On Wed, Dec 14, 2022 at 08:36:47AM +0200, Tomi Valkeinen wrote:
> >> On 14/12/2022 08:29, Tomi Valkeinen wrote:
> >>
> >>>> wondering if the struct device of the DS90UB913 could be passed instead
> >>>> of the port, to avoid passing the port throught
> >>>> ds90ub9xx_platform_data.
> >>>
> >>> Interesting thought. That would limit the number of remote i2c busses to
> >>> one, though. Not a problem for FPD-Link, but I wonder if that's assuming
> >>> too much for the future users. Then again, this is an in-kernel API so
> >>> we could extend it later if needed. So I'll try this out and see if I
> >>> hit any issues.
> >>
> >> Right, so the issue with this one would be that it would prevent a
> >> single device uses. E.g. a single chip which acts as an ATR (similar to
> >> i2c-mux chips), i.e. it contains both the main and the remote i2c busses.
> >
> > I don't think I understand this, sorry.
>
> What you are suggesting above means that we'd have a separate device for
> each port of the ATR. Which is fine in our current case, as the i2c
> master busses are behind separate remote devices.
>
> But if you consider a case similar to i2c-mux, where we have a single
> chip with the slave bus and, say, 4 master busses. We would probably
> have only a single device for that.

Hmmm... Yes you're right, it won't work in that case. Maybe we could
have two functions, the existing i2c_atr_add_adapter(), and another one
that wraps it ? It would be nice if we could get rid of the platform
data for the UB913 and UB953 drivers.

--
Regards,

Laurent Pinchart