Re: [PATCH v14 01/10] dt-bindings: mediatek,dp: Add Display Port binding

Rex-BC Chen
2022-07-26T06:23:39Z

On Wed, 2022-07-13 at 15:56 +0800, CK Hu wrote:
> Hi, Bo-Chen:
>
> On Tue, 2022-07-12 at 19:12 +0800, Bo-Chen Chen wrote:
> > From: Markus Schneider-Pargmann <msp@baylibre.com>
> >
> > This controller is present on several mediatek hardware. Currently
> > mt8195 and mt8395 have this controller without a functional
> > difference,
> > so only one compatible field is added.
> >
> > The controller can have two forms, as a normal display port and as
> > an
> > embedded display port.
> >
> > Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
> > Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
> > Signed-off-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
> > ---
> > .../display/mediatek/mediatek,dp.yaml | 115
> > ++++++++++++++++++
> > 1 file changed, 115 insertions(+)
> > create mode 100644
> > Documentation/devicetree/bindings/display/mediatek/mediatek,dp.yaml
> >
> > diff --git
> > a/Documentation/devicetree/bindings/display/mediatek/mediatek,dp.ya
> > ml
> > b/Documentation/devicetree/bindings/display/mediatek/mediatek,dp.ya
> > ml
> > new file mode 100644
> > index 000000000000..e2d6cb314297
> > --- /dev/null
> > +++
> > b/Documentation/devicetree/bindings/display/mediatek/mediatek,dp.ya
> > ml
> > @@ -0,0 +1,115 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id:
> > http://devicetree.org/schemas/display/mediatek/mediatek,dp.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: MediaTek Display Port Controller
> > +
> > +maintainers:
> > + - Chun-Kuang Hu <chunkuang.hu@kernel.org>
> > + - Jitao shi <jitao.shi@mediatek.com>
> > +
> > +description: |
> > + Device tree bindings for the MediaTek display port TX (DP) and
> > + embedded display port TX (eDP) controller present on some
> > MediaTek
> > SoCs.
> > + MediaTek DP and eDP are different hardwares and they have
> > different
> > + base address for registers, so we need two different compatibles
> > to
> > + separate them.
> > +
> > +properties:
> > + compatible:
> > + enum:
> > + - mediatek,mt8195-dp-tx
> > + - mediatek,mt8195-edp-tx
> > +
> > + reg:
> > + maxItems: 1
> > +
> > + nvmem-cells:
> > + maxItems: 1
> > + description: efuse data for display port calibration
> > +
> > + nvmem-cell-names:
> > + const: dp_calibration_data
> > +
> > + power-domains:
> > + maxItems: 1
> > +
> > + interrupts:
> > + maxItems: 1
> > +
> > + ports:
> > + $ref: /schemas/graph.yaml#/properties/ports
> > + properties:
> > + port@0:
> > + $ref: /schemas/graph.yaml#/properties/port
> > + description: Input endpoint of the controller, usually
> > dp_intf
> > +
> > + port@1:
> > + $ref: /schemas/graph.yaml#/$defs/port-base
> > + unevaluatedProperties: false
> > + description: Output endpoint of the controller
> > + properties:
> > + endpoint:
> > + $ref: /schemas/media/video-interfaces.yaml#
> > + unevaluatedProperties: false
> > + properties:
> > + data-lanes:
> > + description: |
> > + number of lanes supported by the hardware.
> > + The possible values:
> > + 0 - For 1 lane enabled in IP.
> > + 0 1 - For 2 lanes enabled in IP.
> > + 0 1 2 3 - For 4 lanes enabled in IP.
> > + minItems: 1
> > + maxItems: 4
> > + required:
> > + - data-lanes
> > +
> > + required:
> > + - port@0
> > + - port@1
> > +
> > + max-linkrate-mhz:
> > + enum: [ 1620, 2700, 5400, 8100 ]
> > + description: maximum link rate supported by the hardware.
> > +
> > +required:
> > + - compatible
> > + - reg
> > + - interrupts
> > + - ports
> > + - max-linkrate-mhz
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > + #include <dt-bindings/interrupt-controller/arm-gic.h>
> > + #include <dt-bindings/power/mt8195-power.h>
> > + dp_tx@1c600000 {
> > + compatible = "mediatek,mt8195-dp-tx";
> > + reg = <0x1c600000 0x8000>;
> > + power-domains = <&spm MT8195_POWER_DOMAIN_DP_TX>;
> > + interrupts = <GIC_SPI 458 IRQ_TYPE_LEVEL_HIGH 0>;
> > + max-linkrate-mhz = <8100>;
>
> Why dp-tx has no clock property? I think this device should work with
> a
> clock.
>
> Regards,
> CK
>

Hello CK,

We just need to enable the power domain of dp.
The clock of dp is generated by itself and we are not using the global
pll to generate clocks.

BRs,
Bo-Chen

> > +
> > + ports {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + port@0 {
> > + reg = <0>;
> > + dptx_in: endpoint {
> > + remote-endpoint = <&dp_intf0_out>;
> > + };
> > + };
> > + port@1 {
> > + reg = <1>;
> > + dptx_out: endpoint {
> > + data-lanes = <0 1 2 3>;
> > + };
> > + };
> > + };
> > + };
>
>