Hi Nikolaus,
Le dim., nov. 7 2021 at 14:43:33 +0100, H. Nikolaus Schaller
<hns@xxxxxxxxxxxxx> a écrit :
Hi,
Am 05.10.2021 um 22:43 schrieb Paul Cercueil <paul@xxxxxxxxxxxxxxx>:
Hi Nikolaus,
Le mar., oct. 5 2021 at 14:29:15 +0200, H. Nikolaus Schaller
<hns@xxxxxxxxxxxxx> a écrit :
From: Sam Ravnborg <sam@xxxxxxxxxxxx>
Add DT bindings for the hdmi driver for the Ingenic JZ4780 SoC.
Based on .txt binding from Zubair Lutfullah Kakakhel
Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
---
.../bindings/display/ingenic-jz4780-hdmi.yaml | 79
+++++++++++++++++++
1 file changed, 79 insertions(+)
create mode 100644
Documentation/devicetree/bindings/display/ingenic-jz4780-hdmi.yaml
diff --git
a/Documentation/devicetree/bindings/display/ingenic-jz4780-hdmi.yaml
b/Documentation/devicetree/bindings/display/ingenic-jz4780-hdmi.yaml
new file mode 100644
index 000000000000..5bcb342da86f
--- /dev/null
+++
b/Documentation/devicetree/bindings/display/ingenic-jz4780-hdmi.yaml
@@ -0,0 +1,79 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id:
http://devicetree.org/schemas/display/ingenic-jz4780-hdmi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Bindings for Ingenic JZ4780 HDMI Transmitter
+
+maintainers:
+ - H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
+
+description: |
+ The HDMI Transmitter in the Ingenic JZ4780 is a Synopsys
DesignWare HDMI 1.4
+ TX controller IP with accompanying PHY IP.
My dmesg disagrees:
dw-hdmi-ingenic 10180000.hdmi: Detected HDMI TX controller v1.31a
with HDCP (DWC HDMI 3D TX PHY)
mine as well.
Or am I comparing apples to oranges?
There is a document called "JZ4780 High Efficiency Engine for Mobile
Device"
(JZ4780_PB.pdf) which says
"24-bit parallel/serial TFT interface, HDMI 1.4a interface, LVDS
interface"
And the data sheet ("JZ4780 Mobile Application Processor Data Sheet
") says: "Support HDMI 1.4a Interface"
Finally, the programming manual also says "Support HDMI 1.4a
Interface".
So what is correct?
dmesg may return something else. E.g. silicon revision 1.31a
while the interface is HDMI protocol revision 1.4a compatible?
Trying to find something about "hdmi 1.31a" did only lead to some
"Synopsys' HAPS-51 eval platform" [1].
Looking at HDMI standards [2] I can only find HDMI 1.3 and 1.3a but
no HDMI 1.31a.
[1]
https://www.digital-cp.com/hdcp-products/haps51-hdmi-tx-platform-dwc-hdmi-tx-controller-131a-ea-hdmi-3d-tx-phy-tsmc40g-ip
[2] https://en.wikipedia.org/wiki/HDMI#Version_1.3
Well it may also be some Synopsys-internal designation 1.31a
referring so something
newer than HDMI 1.3a which became the HDMI 1.4 standard (released
June 2009)...
Whom should we believe? What the chip tells or what the data sheet
and programming
manual says?
I tend to keep confusion low and stay with "HDMI 1.4" in the bindings
because
there is no offical "HDMI 1.31a" standard. And HDMI 1.4 was already
some years old
when the jz4780 was released. So it is likely that the chip
identification just
returns 1.31a (maybe Ingenic licenced an interim release VHDL)
although the standard
was later officially named 1.4a.
Fair enough. Let's keep "HDMI 1.4" until proven otherwise.
Cheers,
-Paul
+
+allOf:
+ - $ref: bridge/synopsys,dw-hdmi.yaml#
+
+properties:
+ compatible:
+ const: ingenic,jz4780-dw-hdmi
+
+ reg-io-width:
+ const: 4
+
+ clocks:
+ maxItems: 2
+
+ hdmi-5v-supply:
+ description: Optional regulator to provide +5V at the
connector
+
+ ddc-i2c-bus:
+ description: An I2C interface if the internal DDC I2C driver
is not to be used
This property is used within
(drivers/gpu/drm/bridge/synopsys/dw-hdmi.c); I think it would make
sense to move it to bridge/synopsys,dw-hdmi.yaml.
It is indeed more general and not jz4780 specific. I'll move it for
v6.
BR and thanks,
Nikolaus
