Re: [RFC PATCH v2 19/21] ARM: dts: exynos5250-arndale: add dsi and panel nodes

[Andrzej Hajda <a.hajda@samsung.com>]

On 03/07/2014 02:28 PM, Tomi Valkeinen wrote:
(...)
> There are many possible connections from FIMD, some of them:
> FIMD ---> RGB panel, external
> FIMD ---> DSI, on SoC
> FIMD ---> eDP, on SoC
> FIMD ---> ImageEnhacer, on SoC
> This sounds similar to OMAP, at least roughly.
>
>> In the first case port should be created.
>> In other cases connection could be determined by presence/absence
>> of specific nodes, so in fact the port can be optional, almost like in
>> my proposal :)
> Well, I think not.
>
> In the external encoder case, the ports are there, and they are used.
> You just didn't specify them, and thus make the driver deduce them from
> the DT.
>
> In the FIMD case, if the the RGB port is needed, you need to specify it
> in the DT data, and it's used. If you only need, say, DSI, the RGB port
> is not used and thus it doesn't need to be present in the DT data.
>
> It's fine to leave the port definition out if it is not used at all.
On Exynos, DSI is in fact RGB/DSI encoder (or I80/DSI). DSI and RGB pins
are connected to the same FIMD output. So from FIMD point of view
RGB port is used in both cases.
>
>>> For OMAP, the SoC's display blocks are all inside one bigger DSS
>>> "container", so I have not seen need to represent the connections
>>> between the internal components in the DT data.
>> How do you deal with situation when IPs in SoC can be connected in
>> different ways ?
> Basically so that (using exynos terms) if, say DSI panel is to be
> enabled, the DSI panel driver will reserve the DSI master for itself,
> and the DSI master will reserve the FIMD for itself, presuming FIMD has
> not already been reserved. When the DSI panel is disabled, FIMD is freed.
>
>  Tomi
>
>