Re: [PATCH 11/14] dt-bindings: display: bridge: Add i.MX8qm/qxp LVDS display bridge binding

From: Laurent Pinchart
Date: Tue Dec 22 2020 - 02:37:32 EST


Hi Liu,

Thank you for the patch.

On Thu, Dec 17, 2020 at 05:59:30PM +0800, Liu Ying wrote:
> This patch adds bindings for i.MX8qm/qxp LVDS display bridge(LDB).
>
> Signed-off-by: Liu Ying <victor.liu@xxxxxxx>
> ---
> .../bindings/display/bridge/fsl,imx8qxp-ldb.yaml | 185 +++++++++++++++++++++
> 1 file changed, 185 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml b/Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
> new file mode 100644
> index 00000000..4e5ff6f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
> @@ -0,0 +1,185 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/bridge/fsl,imx8qxp-ldb.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Freescale i.MX8qm/qxp LVDS Display Bridge
> +
> +maintainers:
> + - Liu Ying <victor.liu@xxxxxxx>
> +
> +description: |
> + The Freescale i.MX8qm/qxp LVDS Display Bridge(LDB) has two channels.
> +
> + For i.MX8qxp LDB, each channel supports up to 24bpp parallel input color
> + format and can map the input to VESA or JEIDA standards. The two channels
> + cannot be used simultaneously, that is to say, the user should pick one of
> + them to use. Two LDB channels from two LDB instances can work together in
> + LDB split mode to support a dual link LVDS display. The channel indexes
> + have to be different. Channel0 outputs odd pixels and channel1 outputs
> + even pixels.

In this case, does the display controller output odd pixels and even
pixels separately to the two LVDS channels, with each channel
effectively be a separate LVDS encoder ? Could you give an example of DT
integration for dual-link LVDS support, with the display controller, two
LDB instances, and a dual-link LVDS panel ?

> +
> + For i.MX8qm LDB, each channel additionally supports up to 30bpp parallel
> + input color format. The two channels can be used simultaneously, either
> + in dual mode or split mode. In dual mode, the two channels output identical
> + data. In split mode, channel0 outputs odd pixels and channel1 outputs even
> + pixels.
> +
> +properties:
> + compatible:
> + enum:
> + - fsl,imx8qm-ldb
> + - fsl,imx8qxp-ldb
> +
> + "#address-cells":
> + const: 1
> +
> + "#size-cells":
> + const: 0
> +
> + clocks:
> + items:
> + - description: pixel clock
> + - description: bypass clock
> +
> + clock-names:
> + items:
> + - const: pixel
> + - const: bypass
> +
> + power-domains:
> + maxItems: 1
> +
> + fsl,syscon:
> + $ref: /schemas/types.yaml#/definitions/phandle
> + description: |
> + A phandle which points to Control and Status Registers(CSR) module.
> +
> + fsl,companion-ldb:
> + $ref: /schemas/types.yaml#/definitions/phandle
> + description: |
> + A phandle which points to companion LDB which is used in LDB split mode.
> +
> +patternProperties:
> + "^channel@[0-1]$":
> + type: object
> + description: Represents a channel of LDB.
> +
> + properties:
> + "#address-cells":
> + const: 1
> +
> + "#size-cells":
> + const: 0
> +
> + reg:
> + description: The channel index.
> + enum: [ 0, 1 ]
> +
> + phys:
> + description: A phandle to the phy module representing the LVDS PHY.
> + maxItems: 1
> +
> + phy-names:
> + const: lvds_phy
> +
> + port@0:
> + type: object
> + description: Input port of the channel.
> +
> + properties:
> + reg:
> + const: 0
> +
> + required:
> + - reg
> +
> + port@1:
> + type: object
> + description: Output port of the channel.
> +
> + properties:
> + reg:
> + const: 1
> +
> + required:
> + - reg
> +
> + required:
> + - "#address-cells"
> + - "#size-cells"
> + - reg
> + - phys
> + - phy-names
> +
> + additionalProperties: false
> +
> +required:
> + - compatible
> + - "#address-cells"
> + - "#size-cells"
> + - clocks
> + - clock-names
> + - power-domains
> + - fsl,syscon
> + - channel@0
> + - channel@1
> +
> +allOf:
> + - if:
> + properties:
> + compatible:
> + contains:
> + const: fsl,imx8qm-ldb
> + then:
> + properties:
> + fsl,companion-ldb: false
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/firmware/imx/rsrc.h>
> + ldb {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + compatible = "fsl,imx8qxp-ldb";
> + clocks = <&clk IMX_SC_R_LVDS_0 IMX_SC_PM_CLK_MISC2>,
> + <&clk IMX_SC_R_LVDS_0 IMX_SC_PM_CLK_BYPASS>;
> + clock-names = "pixel", "bypass";
> + power-domains = <&pd IMX_SC_R_LVDS_0>;
> + fsl,syscon = <&mipi_lvds_0_csr>;
> +
> + channel@0 {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + reg = <0>;
> + phys = <&mipi_lvds_0_phy>;
> + phy-names = "lvds_phy";
> +
> + port@0 {
> + reg = <0>;
> +
> + mipi_lvds_0_ldb_ch0_mipi_lvds_0_pxl2dpi: endpoint {
> + remote-endpoint = <&mipi_lvds_0_pxl2dpi_mipi_lvds_0_ldb_ch0>;
> + };
> + };
> + };
> +
> + channel@1 {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + reg = <1>;
> + phys = <&mipi_lvds_0_phy>;
> + phy-names = "lvds_phy";
> +
> + port@0 {
> + reg = <0>;
> +
> + mipi_lvds_0_ldb_ch1_mipi_lvds_0_pxl2dpi: endpoint {
> + remote-endpoint = <&mipi_lvds_0_pxl2dpi_mipi_lvds_0_ldb_ch1>;
> + };
> + };
> + };
> + };

--
Regards,

Laurent Pinchart