2021-11-26 09:56:57

by Kieran Bingham

Subject: [PATCH v4 4/4] arm64: dts: renesas: r8a779a0: Provide default DSI data-lanes

The data-lanes is a mandatory property for the endpoints.
Provide a default when not connected that represents the maximum
lanes supported by the device.

A connected device should override the data-lanes if it uses a lower
number of lanes.

Signed-off-by: Kieran Bingham <[email protected]>
---

This patch is split from 2/4 to keep it's change for distinct review.
The data-lanes is marked as a mandatory property in the DSI bindings
(which are out of tree, most recent posting at [0])

[0] https://lore.kernel.org/all/YQGFP%[email protected]/

The data-lanes property is marked as mandatory, which means it needs to
be provided even when supplying the port templates which get overridden
later. Is this expected behaviour?

Does this have sufficient meaning? Or will it always have to be
specified by any node overriding anyway...?


arch/arm64/boot/dts/renesas/r8a779a0.dtsi | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r8a779a0.dtsi b/arch/arm64/boot/dts/renesas/r8a779a0.dtsi
index fdad8bc4a069..7322c4628e2b 100644
--- a/arch/arm64/boot/dts/renesas/r8a779a0.dtsi
+++ b/arch/arm64/boot/dts/renesas/r8a779a0.dtsi
@@ -2661,6 +2661,7 @@ dsi0_in: endpoint {
port@1 {
reg = <1>;
dsi0_out: endpoint {
+ data-lanes = <1 2 3 4>;
};
};
};
@@ -2691,7 +2692,9 @@ dsi1_in: endpoint {

port@1 {
reg = <1>;
+
dsi1_out: endpoint {
+ data-lanes = <1 2 3 4>;
};
};
};
--
2.30.2

2021-11-26 13:53:41

by Laurent Pinchart

Subject: Re: [PATCH v4 4/4] arm64: dts: renesas: r8a779a0: Provide default DSI data-lanes

Hi Kieran,

Thank you for the patch.

On Fri, Nov 26, 2021 at 09:54:45AM +0000, Kieran Bingham wrote:
> The data-lanes is a mandatory property for the endpoints.
> Provide a default when not connected that represents the maximum
> lanes supported by the device.
>
> A connected device should override the data-lanes if it uses a lower
> number of lanes.
>
> Signed-off-by: Kieran Bingham <[email protected]>
> ---
>
> This patch is split from 2/4 to keep it's change for distinct review.
> The data-lanes is marked as a mandatory property in the DSI bindings
> (which are out of tree, most recent posting at [0])
>
> [0] https://lore.kernel.org/all/YQGFP%[email protected]/
>
> The data-lanes property is marked as mandatory, which means it needs to
> be provided even when supplying the port templates which get overridden
> later. Is this expected behaviour?
>
> Does this have sufficient meaning? Or will it always have to be
> specified by any node overriding anyway...?

Isn't the remote-endpoint also mandatory ?

Given that there's no real good default value for data-lanes that is
significantly more likely than others, I'd prefer dropping the endpoints
from r8a779a0.dtsi and adding them in board files.

> arch/arm64/boot/dts/renesas/r8a779a0.dtsi | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/renesas/r8a779a0.dtsi b/arch/arm64/boot/dts/renesas/r8a779a0.dtsi
> index fdad8bc4a069..7322c4628e2b 100644
> --- a/arch/arm64/boot/dts/renesas/r8a779a0.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a779a0.dtsi
> @@ -2661,6 +2661,7 @@ dsi0_in: endpoint {
> port@1 {
> reg = <1>;
> dsi0_out: endpoint {
> + data-lanes = <1 2 3 4>;
> };
> };
> };
> @@ -2691,7 +2692,9 @@ dsi1_in: endpoint {
>
> port@1 {
> reg = <1>;
> +
> dsi1_out: endpoint {
> + data-lanes = <1 2 3 4>;
> };
> };
> };

--
Regards,

Laurent Pinchart