Re: [PATCH v3 02/12] dt-bindings: display: mediatek: add MT8195 hdmi bindings

From: AngeloGioacchino Del Regno
Date: Mon Jan 02 2023 - 09:14:48 EST


Il 02/01/23 14:38, Guillaume Ranquet ha scritto:
On Mon, 26 Dec 2022 06:18, CK Hu (胡俊光) <ck.hu@xxxxxxxxxxxx> wrote:
Hi, Guillaume:

On Fri, 2022-11-04 at 15:09 +0100, Guillaume Ranquet wrote:
Add mt8195 SoC bindings for hdmi and hdmi-ddc

On mt8195 the ddc i2c controller is part of the hdmi IP block and
thus has no
specific register range, power domain or interrupt, making it simpler
than its the legacy "mediatek,hdmi-ddc" binding.

Signed-off-by: Guillaume Ranquet <granquet@xxxxxxxxxxxx>
---


[snip]

a/Documentation/devicetree/bindings/display/mediatek/mediatek,mt8195-
hdmi-ddc.yaml
b/Documentation/devicetree/bindings/display/mediatek/mediatek,mt8195-
hdmi-ddc.yaml
new file mode 100644
index 000000000000..2dc273689584
--- /dev/null
+++
b/Documentation/devicetree/bindings/display/mediatek/mediatek,mt8195-
hdmi-ddc.yaml
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id:
https://urldefense.com/v3/__http://devicetree.org/schemas/display/mediatek/mediatek,mt8195-hdmi-ddc.yaml*__;Iw!!CTRNKA9wMg0ARbw!wwVQuq5lzW0lvUFUkVXPWT8cIu96xdkn4tMams1E55qyxEZmgV1i0WfpOlq57w$

+$schema:
https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!CTRNKA9wMg0ARbw!wwVQuq5lzW0lvUFUkVXPWT8cIu96xdkn4tMams1E55qyxEZmgV1i0WdSGOSxzw$

+
+title: Mediatek HDMI DDC for mt8195
+
+maintainers:
+ - CK Hu <ck.hu@xxxxxxxxxxxx>
+ - Jitao shi <jitao.shi@xxxxxxxxxxxx>
+
+description: |
+ The HDMI DDC i2c controller is used to interface with the HDMI DDC
pins.
+
+properties:
+ compatible:
+ enum:
+ - mediatek,mt8195-hdmi-ddc
+
+ clocks:
+ maxItems: 1
+
+ clock-names:
+ items:
+ - const: ddc
+
+ mediatek,hdmi:
+ $ref: /schemas/types.yaml#/definitions/phandle
+ description:
+ A phandle to the mt8195 hdmi controller
+
+required:
+ - compatible
+ - clocks
+ - clock-names
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+ #include <dt-bindings/interrupt-controller/irq.h>
+ hdmiddc0: i2c {
+ compatible = "mediatek,mt8195-hdmi-ddc";
+ mediatek,hdmi = <&hdmi0>;
+ clocks = <&clk26m>;
+ clock-names = "ddc";
+ };

I think we should not have a virtual device. This ddc is part of
mt8195-hdmi device, so just keep mt8195-hdmi, and let mt8195-hdmi
driver to probe the sub driver of ddc driver.

Regards,
CK

Hi CK,

Thx for your input.
Though I would strongly prefer to keep the ddc as a separate "virtual device".

It aligns better with the goal of reusing as much code as possible
from the HDMI V1 IP,
which is something you have been advocating since V1 of this patch
quite some time ago
and has shaped this patch.

To me we are in a state that is clean and avoids branching in the hdmi
common code.
Would you reconsider and allow the use of that virtual device?

Thx,
Guillaume.


You can as well keep the DDC as a separated driver, but register in the HDMI v1 and
v2 driver at probe time.

Doing that, you won't need any devicetree node specific to any virtual device :-)

Cheers,
Angelo