Re: [PATCH 08/22] dt-bindings: display: rockchip: dw-hdmi: use "ref" as clock name

Rob Herring
2021-12-21T14:32:46Z

On Mon, Dec 20, 2021 at 12:06:16PM +0100, Sascha Hauer wrote:
> "vpll" is a misnomer. A clock input to a device should be named after
> the usage in the device, not after the clock that drives it. On the
> rk3568 the same clock is driven by the HPLL.
> To fix that, this patch renames the vpll clock to ref clock.

The problem with this series is it breaks an old kernel with new dt. You
can partially mitigate that with stable kernel backport, but IMO keeping
the old name is not a burden to maintain.

And given RK3399 is widely used including by me, we should not be
breaking compatibility.

So allow for ref in addition to vpll if you like, but only use 'ref' for
new users. And add a comment in the schema to that effect.

Rob

>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
> .../bindings/display/rockchip/rockchip,dw-hdmi.yaml | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml
> index 6e09dd2ee05ac..3b40219e3ea60 100644
> --- a/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml
> +++ b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml
> @@ -47,11 +47,12 @@ properties:
> - enum:
> - cec
> - grf
> - - vpll
> + - ref
> - enum:
> - grf
> - - vpll
> - - const: vpll
> + - ref
> + - const:
> + - ref
>
> ddc-i2c-bus:
> $ref: /schemas/types.yaml#/definitions/phandle
> --
> 2.30.2