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From: Laurent Pinchart <firstname.lastname@example.org> To: Philippe CORNU <email@example.com> Cc: Mark Rutland <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, Alexandre TORGUE <email@example.com>, David Airlie <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, Yannick FERTRE <email@example.com>, Rob Herring <firstname.lastname@example.org> Subject: Re: [PATCH 1/2] dt-bindings/display/bridge: sii902x: add optional power supplies Date: Thu, 19 Apr 2018 15:50:26 +0300 [thread overview] Message-ID: <5933919.oNossTj3O6@avalon> (raw) In-Reply-To: <email@example.com> Hi Philippe, On Thursday, 19 April 2018 15:41:20 EEST Philippe CORNU wrote: > On 04/19/2018 01:09 PM, Laurent Pinchart wrote: > > On Thursday, 19 April 2018 12:31:15 EEST Philippe CORNU wrote: > >> On 04/19/2018 10:11 AM, Laurent Pinchart wrote: > >>> On Tuesday, 10 April 2018 08:19:26 EEST Philippe Cornu wrote: > >>>> Add the 3 optional power supplies using the exact description > >>>> found in the document named > >>>> "SiI9022A/SiI9024A HDMI Transmitter Data Sheet (August 2016)". > >>>> > >>>> Signed-off-by: Philippe Cornu <firstname.lastname@example.org> > >>>> --- > >>>> > >>>> Documentation/devicetree/bindings/display/bridge/sii902x.txt | 3 +++ > >>>> 1 file changed, 3 insertions(+) > >>>> > >>>> diff --git > >>>> a/Documentation/devicetree/bindings/display/bridge/sii902x.txt > >>>> b/Documentation/devicetree/bindings/display/bridge/sii902x.txt index > >>>> 56a3e68ccb80..cf53678fe574 100644 > >>>> --- a/Documentation/devicetree/bindings/display/bridge/sii902x.txt > >>>> +++ b/Documentation/devicetree/bindings/display/bridge/sii902x.txt > >>>> @@ -8,6 +8,9 @@ Optional properties: > >>>> - interrupts-extended or interrupt-parent + interrupts: describe > >>>> the interrupt line used to inform the host about hotplug events. > >>>> - reset-gpios: OF device-tree gpio specification for RST_N pin. > >>>> + - iovcc-supply: I/O supply voltage (1.8V or 3.3V, host-dependent). > >>>> + - avcc12-supply: TMDS analog supply voltage (1.2V). > >>>> + - cvcc12-supply: Digital core supply voltage (1.2V). > >>> > >>> It seems that the AVCC12 and CVCC12 power supplies are usually derived > >>> from the same source. How about starting with one DT property for both, > >>> and adding a second one later if needed ? > >> > >> Well, I do not know what is the best. Here I took the description from > >> the documentation, and to allow all possible board configurations, I > >> added these supplies as "optional" properties: if there is only one 1v2 > >> regulator on the board, the dt will contain only avcc12 or cvcc12 and > >> everything will work fine (we will have a dummy regulator for the > >> missing optional 1v2 reg), if both regulators are there for any reasons > >> (stability, noise, whatever...) then both entries will be in the dt. > >> > >> If you confirm you prefer a single 1v2 supply (named for instance > >> "vcc12-supply") then I will do :-) > > > > Please see https://lists.freedesktop.org/archives/dri-devel/2018-April/ > > 172400.html (and the messages that lead to it) and https:// > > lists.freedesktop.org/archives/dri-devel/2018-March/170763.html. > > Thanks for this discussion thread. > > On my side, I found "CVCC12 and AVCC12 can be derived from the same > power source" written with a small font (august 2016 datasheet p13) so > then your advice is clearly what we have to do :-) > I will add this info in v2 too. I have seen that too. While the datasheet only says that the two supplies *can* be derived from the same power source, I expect that to be the case in practice for a really vast majority of cases (I wouldn't be surprised to never hear of a system using two different supplies). That's why I think starting with one supply would be better. > >>>> Optional subnodes: > >>>> > >>>> - video input: this subnode can contain a video input port node -- Regards, Laurent Pinchart
next prev parent reply other threads:[~2018-04-19 12:50 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-04-10 5:19 [PATCH 0/2] drm/bridge: sii902x: add optional power supplies Philippe Cornu 2018-04-10 5:19 ` [PATCH 1/2] dt-bindings/display/bridge: " Philippe Cornu 2018-04-13 17:58 ` Rob Herring 2018-04-19 8:11 ` Laurent Pinchart 2018-04-19 9:31 ` Philippe CORNU 2018-04-19 11:09 ` Laurent Pinchart 2018-04-19 12:41 ` Philippe CORNU 2018-04-19 12:50 ` Laurent Pinchart [this message] 2018-04-10 5:19 ` [PATCH 2/2] drm/bridge: " Philippe Cornu 2018-04-19 8:20 ` Laurent Pinchart 2018-04-19 9:46 ` Philippe CORNU 2018-04-19 11:00 ` Laurent Pinchart
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