Re: [RFC PATCH 1/9] dt-bindings: display: bridge: Add Samsung SEC MIPI DSIM bindings

[Laurent Pinchart]

Hi Jagan,

Thank you for the patch.

On Mon, Jun 21, 2021 at 12:54:16PM +0530, Jagan Teki wrote:
> Samsung SEC MIPI DSIM Bridge controller is MIPI DSI bridge
> available in NXP's i.MX8M Mini and Nano Processors.
> 
> Add dt-bingings for it.
> 
> Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> Cc: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> Cc: Robert Foss <robert.foss@xxxxxxxxxx>
> Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> ---
>  .../display/bridge/samsung,sec-dsim.yaml      | 184 ++++++++++++++++++
>  1 file changed, 184 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/samsung,sec-dsim.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/samsung,sec-dsim.yaml b/Documentation/devicetree/bindings/display/bridge/samsung,sec-dsim.yaml
> new file mode 100644
> index 000000000000..32f67f313dfd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/samsung,sec-dsim.yaml
> @@ -0,0 +1,184 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/bridge/samsung,sec-dsim.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Samsung SEC MIPI DSIM Bridge controller on i.MX8M Mini and Nano SoCs
> +
> +maintainers:
> +  - Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> +
> +description: |
> +  NWL MIPI-DSI host controller found on i.MX8 platforms. This is a dsi bridge for
> +  the SOCs NWL MIPI-DSI host controller.
> +
> +allOf:
> +  - $ref: ../dsi-controller.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - fsl,imx8mm-sec-dsim
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +  assigned-clock-parents: true
> +  assigned-clock-rates: true
> +  assigned-clocks: true
> +
> +  clocks:
> +    items:
> +      - description: DSI bus clock
> +      - description: PHY_REF clock
> +
> +  clock-names:
> +    items:
> +      - const: bus
> +      - const: phy_ref
> +
> +  phys:
> +    maxItems: 1
> +    description: phandle to the phy module representing the DPHY
> +
> +  phy-names:
> +    items:
> +      - const: dphy
> +
> +  power-domains:
> +    maxItems: 1
> +    description: phandle to the associated power domain
> +
> +  samsung,burst-clock-frequency:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      DSIM high speed burst mode frequency.
> +
> +  samsung,esc-clock-frequency:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      DSIM escape mode frequency.
> +
> +  samsung,pll-clock-frequency:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      DSIM oscillator clock frequency.

Why do you need those three properties ? They look like configuration
information to me, not system description. If they are needed, their
description needs to explain how to set them. Looking at the three
descriptions above I have no idea what to select for those frequencies.

> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        description:
> +          Input port node to receive pixel data from the
> +          display controller. Exactly one endpoint must be
> +          specified.
> +        properties:
> +          endpoint@0:
> +            $ref: /schemas/graph.yaml#/properties/endpoint
> +            description: sub-node describing the input from LCDIF
> +
> +          endpoint@1:
> +            $ref: /schemas/graph.yaml#/properties/endpoint
> +            description: sub-node describing the input from DCSS
> +
> +        oneOf:
> +          - required:
> +              - endpoint@0
> +          - required:
> +              - endpoint@1
> +
> +        unevaluatedProperties: false
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description:
> +          DSI output port node to the panel or the next bridge
> +          in the chain
> +
> +    required:
> +      - port@0
> +      - port@1
> +
> +required:
> +  - '#address-cells'
> +  - '#size-cells'
> +  - clock-names
> +  - clocks
> +  - compatible
> +  - interrupts
> +  - phy-names
> +  - phys
> +  - ports
> +  - reg
> +  - samsung,burst-clock-frequency
> +  - samsung,esc-clock-frequency
> +  - samsung,pll-clock-frequency
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/imx8mm-clock.h>
> +    #include <dt-bindings/power/imx8mm-power.h>
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    dsi: dsi@32e10000 {
> +      compatible = "fsl,imx8mm-sec-dsim";
> +      reg = <0x32e10000 0xa0>;
> +      clocks = <&clk IMX8MM_CLK_DSI_CORE>,
> +               <&clk IMX8MM_CLK_DSI_PHY_REF>;
> +      clock-names = "bus", "phy_ref";
> +      assigned-clocks = <&clk IMX8MM_CLK_DSI_CORE>,
> +                        <&clk IMX8MM_VIDEO_PLL1_OUT>,
> +                        <&clk IMX8MM_CLK_DSI_PHY_REF>;
> +      assigned-clock-parents = <&clk IMX8MM_SYS_PLL1_266M>,
> +                               <&clk IMX8MM_VIDEO_PLL1_BYPASS>,
> +                               <&clk IMX8MM_VIDEO_PLL1_OUT>;
> +      assigned-clock-rates = <266000000>, <594000000>, <27000000>;
> +      interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH>;
> +      phys = <&dphy>;
> +      phy-names = "dphy";
> +      power-domains = <&dispmix_blk_ctl IMX8MM_BLK_CTL_PD_DISPMIX_MIPI_DSI>;
> +      samsung,burst-clock-frequency = <891000000>;
> +      samsung,esc-clock-frequency = <54000000>;
> +      samsung,pll-clock-frequency = <27000000>;
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +
> +      ports {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        port@0 {
> +          reg = <0>;
> +          #size-cells = <0>;
> +          #address-cells = <1>;
> +
> +          dsi_in_lcdif: endpoint@0 {
> +            reg = <0>;
> +            remote-endpoint = <&lcdif_out_dsi>;
> +          };
> +        };
> +
> +        port@1 {
> +          reg = <1>;
> +
> +          dsi_out_panel: endpoint {
> +            remote-endpoint = <&panel_in_dsi>;
> +          };
> +        };
> +      };
> +    };

-- 
Regards,

Laurent Pinchart