On Sun, Jun 23, 2024 at 04:48:47PM +0200, Marek Vasut wrote: > On 6/22/24 1:56 PM, Conor Dooley wrote: > > On Fri, Jun 21, 2024 at 05:53:53PM +0200, Marek Vasut wrote: > > > Document default DP port preemphasis configurable via new DT property > > > "toshiba,pre-emphasis". This is useful in case the DP link properties > > > are known and starting link training from preemphasis setting of 0 dB > > > is not useful. The preemphasis can be set separately for both DP lanes > > > in range 0=0dB, 1=3.5dB, 2=6dB . > > > > > > Signed-off-by: Marek Vasut <marex@xxxxxxx> > > > --- > > > V2: - Fix the type to u8 array > > > - Fix the enum items to match what they represent > > > --- > > > .../display/bridge/toshiba,tc358767.yaml | 18 ++++++++++++++++++ > > > 1 file changed, 18 insertions(+) > > > > > > diff --git a/Documentation/devicetree/bindings/display/bridge/toshiba,tc358767.yaml b/Documentation/devicetree/bindings/display/bridge/toshiba,tc358767.yaml > > > index 2ad0cd6dd49e0..6287eb2b40908 100644 > > > --- a/Documentation/devicetree/bindings/display/bridge/toshiba,tc358767.yaml > > > +++ b/Documentation/devicetree/bindings/display/bridge/toshiba,tc358767.yaml > > > @@ -98,6 +98,24 @@ properties: > > > reference to a valid eDP panel input endpoint node. This port is > > > optional, treated as DP panel if not defined > > > + properties: > > > + endpoint: > > > + $ref: /schemas/media/video-interfaces.yaml# > > > + unevaluatedProperties: false > > > + > > > + properties: > > > + toshiba,pre-emphasis: > > > + description: > > > + Display port output Pre-Emphasis settings for both ports. > > > > Why here and not in the port nodes? > > There was a short discussion about that in V1: > > https://lore.kernel.org/all/00e9ef90-3bbe-4556-8da9-462f65928781@xxxxxxx/ > > " > Let's keep it in the endpoint node. > > There is some mention in the TC9595 datasheet that the DP might operate > in some split mode, where each DP lane is used to feed one display (?), > so I assume in that case there might be two endpoints (?), but that is > not supported right now. > > If that is ever needed, I guess this array would have minItems 1 and > maxItems 2 and another endpoint would be added to the schema for this > port 2. > " Can this be put in the commit message please? > > > + $ref: /schemas/types.yaml#/definitions/uint8-array > > > + minItems: 2 > > > + maxItems: 2 > > > + items: > > > + enum: > > > + - 0 # No pre-emphasis > > > + - 1 # 3.5dB pre-emphasis > > > + - 2 # 6dB pre-emphasis > > > > I'd love to say please make this -bB and put this in units, but that'd > > require it being a string.. > > I can do that. Do you think that's worth it ? I dunno, I'd advocate for it for any other unit cos I would ask for the unit to be changed into something that didn't require fractions. But for decibels, that just going to be confusing given how it works. I think for dB it's just not worth it.
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