Hi Tomi,
Thank you for taking a look at the patches!
On 17-Jan-23 18:08, Tomi Valkeinen wrote:
On 09/01/2023 18:21, Aradhya Bhatia wrote:
Hi Angelo,
Thanks for taking a look at the patches!
On 03-Jan-23 17:21, AngeloGioacchino Del Regno wrote:
Il 03/01/23 07:46, Aradhya Bhatia ha scritto:
Dual-link LVDS interfaces have 2 links, with even pixels traveling on
one link, and odd pixels on the other. These panels are also generic in
nature, with no documented constraints, much like their single-link
counterparts, "panel-lvds".
Add a new compatible, "panel-dual-lvds", and a dt-binding document for
these panels.
Signed-off-by: Aradhya Bhatia <a-bhatia1@xxxxxx>
---
.../display/panel/panel-dual-lvds.yaml | 157
++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 158 insertions(+)
create mode 100644
Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
diff --git
a/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
new file mode 100644
index 000000000000..88a7aa2410be
--- /dev/null
+++
b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
@@ -0,0 +1,157 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/panel-dual-lvds.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic Dual-Link LVDS Display Panel
+
+maintainers:
+ - Aradhya Bhatia <a-bhatia1@xxxxxx>
+ - Thierry Reding <thierry.reding@xxxxxxxxx>
+
+description: |
+ A dual-LVDS interface is a dual-link connection with the even pixels
+ traveling on one link, and the odd pixels traveling on the other.
+
+allOf:
+ - $ref: panel-common.yaml#
+ - $ref: /schemas/display/lvds.yaml/#
+
+properties:
+ compatible:
+ oneOf:
+ - items:
+ - enum:
+ - lincolntech,lcd185-101ct
+ - microtips,13-101hieb0hf0-s
+ - const: panel-dual-lvds
+ - const: panel-dual-lvds
+
+ ports:
+ $ref: /schemas/graph.yaml#/properties/ports
+
+ properties:
+ port@0:
+ $ref: /schemas/graph.yaml#/$defs/port-base
+ unevaluatedProperties: false
+ description: The sink for first set of LVDS pixels.
+
+ properties:
+ dual-lvds-odd-pixels:
+ type: boolean
+
+ dual-lvds-even-pixels:
+ type: boolean
+
+ oneOf:
+ - required: [dual-lvds-odd-pixels]
One question: why do we need a "panel-dual-lvds" compatible?
A Dual-LVDS panel is a LVDS panel using two ports, hence still a
panel-lvds.
If you're doing this to clearly distinguish, for human readability purposes,
single-link vs dual-link panels, I think that this would still be clear even
if we use panel-lvds alone because dual-link panels, as you wrote in this
binding, does *require* two ports, with "dual-lvds-{odd,even}-pixels" properties.
Yes, while they are both LVDS based panels the extra LVDS sink in these
panels, and the capability to decode and display the 2 sets of signals
are enough hardware differences that warrant for an addition of a new
compatible.
So... the devicetree node would look like this:
panel {
compatible = "vendor,panel", "panel-lvds";
....
ports {
port@0 {
.....
-> dual-lvds-odd-pixels <-
}
port@1 {
.....
-> dual-lvds-even-pixels <-
};
};
};
+ - required: [dual-lvds-even-pixels]
...Though, if you expect dual-lvds panels to get other quirks in the future,
that's a whole different story and you may actually need the panel-dual-lvds
compatible.
Yes, exactly. Even while being non-smart, there are going to be more
quirks in future. And it would be better if they have their own
compatible/binding, and are not getting appended in an ever-growing
if-else ladder. :)
I can imagine a panel which you can use with a single LVDS link if the
clock is high enough, or two LVDS links if the clock has to be lower. Is
that a dual-lvds panel? =)
Hmm, I can see what you are saying here.
If one wants to run a dual-link panel, with 1 link (given enough clock
frequency), then the bindings here will *not* allow for a single port
with the odd/even properties absent.
In such a case, the compatible will indeed need to be changed to
"panel-lvds".
While it does feel a tad bit odd, I believe it is still worth
maintaining the clarity and HW differences between the single and dual
link panels. :)
But probably that situation is no different than a panel that can work
with DSI or DPI input.
Still, I'm agree with Angelo in that a new compatible string for dual
link lvds feels a bit odd. That said, it's possible the panel-lvds > bindings might get rather confusing. So I don't have a strong feeling
here.
Regards
Aradhya
