Re: [PATCH v2 1/2] dt-bindings: display: rockchip: Add compatible for rk3568 HDMI

Hi Michael,

Am Dienstag, 13. Juli 2021, 10:44:00 CEST schrieb Michael Riesch:

The HDMI TX block in the RK3568 requires two power supplies, which have
to be enabled in some cases (at least on the RK3568 EVB1 the voltages
VDDA0V9_IMAGE and VCCA1V8_IMAGE are disabled by default). It would be
great if this was considered by the driver and the device tree binding.
I am not sure, though, whether this is a RK3568 specific or
rockchip_dw_hdmi specific thing. Maybe it can even enter the Synopsis DW
HDMI driver.

I do remember that this discussion happened many years back already.
And yes the supplies are needed for all but back then there was opposition
as these are supposedly phy-related supplies, not for the dw-hdmi itself.
[There are variants with an external phy, like on the rk3328]

See discussion on [0]

[0] https://dri-devel.freedesktop.narkive.com/pen2zWo1/patch-v3-1-2-drm-bridge-dw-hdmi-support-optional-supply-regulators

On 7/7/21 2:03 PM, Benjamin Gaignard wrote:

quoted

Define a new compatible for rk3568 HDMI.
This version of HDMI hardware block needs two new clocks hclk_vio and hclk
to provide phy reference clocks.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
version 2:
- Add the clocks needed for the phy.

 .../bindings/display/rockchip/rockchip,dw-hdmi.yaml         | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml
index 75cd9c686e985..cb8643b3a8b84 100644
--- a/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml
+++ b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml

@@ -23,6 +23,7 @@ properties:
       - rockchip,rk3288-dw-hdmi
       - rockchip,rk3328-dw-hdmi
       - rockchip,rk3399-dw-hdmi
+      - rockchip,rk3568-dw-hdmi
 
   reg-io-width:
     const: 4

@@ -51,8 +52,11 @@ properties:
           - vpll
       - enum:
           - grf
+          - hclk_vio
+          - vpll
+      - enum:
+          - hclk
           - vpll
-      - const: vpll

The description and documentation of the clocks are somewhat misleading
IMHO. This is not caused by your patches, of course. But maybe this is a
chance to clean them up a bit.

It seems that the CEC clock is an optional clock of the dw-hdmi driver.
Shouldn't it be documented in the synopsys,dw-hdmi.yaml?

Also, it would be nice if the clocks hclk_vio and hclk featured a
description in the binding.

BTW, I am not too familiar with the syntax here, but shouldn't items in
clocks and items in clock-names be aligned (currently, there is a plain
list vs. an enum structure)?

Best regards,
Michael

quoted

 
   ddc-i2c-bus:
     $ref: /schemas/types.yaml#/definitions/phandle

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