Re: [PATCH v4 2/3] dt-bindings: display: ti: Add schema for AM625 OLDI Transmitter

[Rob Herring <robh@kernel.org>]

On Sun, Nov 24, 2024 at 08:06:48PM +0530, Aradhya Bhatia wrote:
> From: Aradhya Bhatia <a-bhatia1@ti.com>
> 
> The OLDI transmitters (TXes) do not have registers of their own, and are
> dependent on the source video-ports (VPs) from the DSS to provide
> configuration data. This hardware doesn't directly sit on the internal
> bus of the SoC, but does so via the DSS. Hence, the OLDI TXes are
> supposed to be child nodes under the DSS, and not independent devices.
> 
> Two of the OLDI TXes can function in tandem to output dual-link OLDI
> output, or cloned single-link outputs. In these cases, one OLDI will be
> the primary OLDI, and the other one, a companion. The following diagram
> represents such a configuration.
> 
> +-----+-----+         +-------+
> |     |     |         |       |
> |     | VP1 +----+--->+ OLDI0 |  (Primary - may need companion)
> |     |     |    |    |       |
> | DSS +-----+    |    +-------+
> |     |     |    |
> |     | VP2 |    |    +-------+
> |     |     |    |    |       |
> +-----+-----+    +--->+ OLDI1 |  (Companion OLDI)
>                       |       |
>                       +-------+
> 
> The DSS in AM625 SoC has a configuration like the one above. The AM625
> DSS VP1 (port@0) can connect and control 2 OLDI TXes, to use them in
> dual-link or cloned single-link OLDI modes. It is only the VP1 that can
> connect to either OLDI TXes for the AM625 DSS, and not the VP2.
> 
> Alternatively, on some future TI SoCs, along with the above
> configuration, the OLDI TX can _also_ connect to separate video sources,
> making them work entirely independent of each other. In this case,
> neither of the OLDIs are "companion" or "secondary" OLDIs, and nor do
> they require one. They both are independent and primary OLDIs. The
> following diagram represents such a configuration.
> 
> +-----+-----+               +-------+
> |     |     |               |       |
> |     | VP1 +--+----------->+ OLDI0 |  (Primary - may need companion)
> |     |     |  |            |       |
> |     +-----+  |            +-------+
> |     |     |  |
> |     | VP2 |  |
> |     |     |  |
> | DSS +-----+  |   +---+    +-------+
> |     |     |  +-->+ M |    |       |
> |     | VP3 +----->+ U +--->+ OLDI1 |  (Companion or Primary)
> |     |     |      | X |    |       |
> |     +-----+      +---+    +-------+
> |     |     |
> |     | VP4 |
> |     |     |
> +-----+-----+
> 
> Note that depending on the mux configuration, the OLDIs can either be
> working together in tandem - sourced by VP1, OR, they could be working
> independently sourced by VP1 and VP3 respectively.
> The idea is to support all the configurations with this OLDI TX schema.
> 
> The OLDI functionality is further supported by a system-control module,
> which contains a few registers to control OLDI IO power and other
> electrical characteristics of the IO lanes.
> 
> Add devicetree binding schema for the OLDI TXes to support various
> configurations, and extend their support to the AM625 DSS.
> 
> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
> Signed-off-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
> ---
>  .../bindings/display/ti/ti,am625-oldi.yaml    | 119 ++++++++++++++
>  .../bindings/display/ti/ti,am65x-dss.yaml     | 153 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  3 files changed, 273 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/ti/ti,am625-oldi.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/ti/ti,am625-oldi.yaml b/Documentation/devicetree/bindings/display/ti/ti,am625-oldi.yaml
> new file mode 100644
> index 000000000000..51b24db04e89
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/ti/ti,am625-oldi.yaml
> @@ -0,0 +1,119 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/ti/ti,am625-oldi.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Texas Instruments AM625 OLDI Transmitter
> +
> +maintainers:
> +  - Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> +  - Aradhya Bhatia <aradhya.bhatia@linux.dev>
> +
> +description:
> +  The AM625 TI Keystone OpenLDI transmitter (OLDI TX) supports serialized RGB
> +  pixel data transmission between host and flat panel display over LVDS (Low
> +  Voltage Differential Sampling) interface. The OLDI TX consists of 7-to-1 data
> +  serializers, and 4-data and 1-clock LVDS outputs. It supports the LVDS output
> +  formats "jeida-18", "jeida-24" and "vesa-18", and can accept 24-bit RGB or
> +  padded and un-padded 18-bit RGB bus formats as input.
> +
> +properties:
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +    description: serial clock input for the OLDI transmitters
> +
> +  clock-names:
> +    const: serial
> +
> +  ti,companion-oldi:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      phandle to companion OLDI transmitter. This property is mandatory for the
> +      primarty OLDI TX if the OLDI TXes are expected to work either in dual-lvds
> +      mode or in clone mode. This property should point to the secondary OLDI
> +      TX.
> +
> +  ti,secondary-oldi:
> +    type: boolean
> +    description:
> +      Boolean property to mark the OLDI transmitter as the secondary one, when the
> +      OLDI hardware is expected to run as a companion HW, in cases of dual-lvds
> +      mode or clone mode. The primary OLDI hardware is responsible for all the
> +      hardware configuration.
> +
> +  ti,oldi-io-ctrl:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      phandle to syscon device node mapping OLDI IO_CTRL registers found in the
> +      control MMR region. These registers are required to toggle the I/O lane
> +      power, and control its electrical characteristics.
> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: Parallel RGB input port
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: LVDS output port
> +
> +    required:
> +      - port@0
> +      - port@1
> +
> +allOf:
> +  - if:
> +      required:
> +        - ti,secondary-oldi
> +    then:
> +      properties:
> +        ti,companion-oldi: false
> +
> +required:
> +  - reg
> +  - clocks
> +  - clock-names
> +  - ti,oldi-io-ctrl
> +  - ports
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/soc/ti,sci_pm_domain.h>
> +
> +    oldi-transmitters {

Drop the example here. It's incomplete without the parent and it is 
never validated with this schema because there is no way to select it.

> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +        oldi: oldi@0 {
> +            reg = <0>;
> +            clocks = <&k3_clks 186 0>;
> +            clock-names = "serial";
> +            ti,oldi-io-ctrl = <&dss_oldi_io_ctrl>;
> +            ports {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +                port@0 {
> +                    reg = <0>;
> +                    oldi_in: endpoint {
> +                        remote-endpoint = <&dpi_out>;
> +                    };
> +                };
> +                port@1 {
> +                    reg = <1>;
> +                    oldi_out: endpoint {
> +                        remote-endpoint = <&panel_in>;
> +                    };
> +                };
> +            };
> +        };
> +    };
> +
> +...
> diff --git a/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml b/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
> index 399d68986326..eb6a65f9970d 100644
> --- a/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
> +++ b/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
> @@ -91,6 +91,24 @@ properties:
>            For AM625 DSS, the internal DPI output port node from video
>            port 1.
>            For AM62A7 DSS, the port is tied off inside the SoC.
> +        properties:
> +          endpoint@0:
> +            $ref: /schemas/graph.yaml#/properties/endpoint
> +            description:
> +              For AM625 DSS, VP Connection to OLDI0.
> +              For AM65X DSS, OLDI output from the SoC.
> +
> +          endpoint@1:
> +            $ref: /schemas/graph.yaml#/properties/endpoint
> +            description:
> +              For AM625 DSS, VP Connection to OLDI1.
> +
> +        anyOf:
> +          - required:
> +              - endpoint
> +          - required:
> +              - endpoint@0
> +              - endpoint@1
>  
>        port@1:
>          $ref: /schemas/graph.yaml#/properties/port
> @@ -112,6 +130,26 @@ properties:
>        Input memory (from main memory to dispc) bandwidth limit in
>        bytes per second
>  
> +  oldi-transmitters:
> +    description:
> +      Child node under the DSS, to describe all the OLDI transmitters connected
> +      to the DSS videoports.
> +    type: object
> +    additionalProperties: false

blank line here.

> +    properties:
> +      "#address-cells":
> +        const: 1
> +
> +      "#size-cells":
> +        const: 0
> +
> +    patternProperties:
> +      '^oldi@[0-1]$':
> +        type: object
> +        $ref: ti,am625-oldi.yaml#
> +        unevaluatedProperties: false
> +        description: OLDI transmitters connected to the DSS VPs

You can drop 'type' and 'unevaluatedProperties' here.

> +
>  allOf:
>    - if:
>        properties:
> @@ -123,6 +161,19 @@ allOf:
>          ports:
>            properties:
>              port@0: false
> +            oldi-transmitters: false
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: ti,am65x-dss
> +    then:
> +      properties:
> +        oldi-transmitters: false
> +        port@0:

You missed a level with 'ports'.

> +          properties:
> +            endpoint@1: false
>  
>  required:
>    - compatible
> @@ -171,3 +222,105 @@ examples:
>              };
>          };
>      };
> +
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    #include <dt-bindings/soc/ti,sci_pm_domain.h>
> +
> +    bus {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +        dss1: dss@30200000 {
> +            compatible = "ti,am625-dss";
> +            reg = <0x00 0x30200000 0x00 0x1000>, /* common */
> +                  <0x00 0x30202000 0x00 0x1000>, /* vidl1 */
> +                  <0x00 0x30206000 0x00 0x1000>, /* vid */
> +                  <0x00 0x30207000 0x00 0x1000>, /* ovr1 */
> +                  <0x00 0x30208000 0x00 0x1000>, /* ovr2 */
> +                  <0x00 0x3020a000 0x00 0x1000>, /* vp1 */
> +                  <0x00 0x3020b000 0x00 0x1000>, /* vp2 */
> +                  <0x00 0x30201000 0x00 0x1000>; /* common1 */
> +            reg-names = "common", "vidl1", "vid",
> +                        "ovr1", "ovr2", "vp1", "vp2", "common1";
> +            power-domains = <&k3_pds 186 TI_SCI_PD_EXCLUSIVE>;
> +            clocks =        <&k3_clks 186 6>,
> +                            <&vp1_clock>,
> +                            <&k3_clks 186 2>;
> +            clock-names = "fck", "vp1", "vp2";
> +            interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
> +            oldi-transmitters {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +                oldi0: oldi@0 {
> +                    reg = <0>;
> +                    clocks = <&k3_clks 186 0>;
> +                    clock-names = "serial";
> +                    ti,companion-oldi = <&oldi1>;
> +                    ti,oldi-io-ctrl = <&dss_oldi_io_ctrl>;
> +                    ports {
> +                        #address-cells = <1>;
> +                        #size-cells = <0>;
> +                        port@0 {
> +                            reg = <0>;
> +                            oldi0_in: endpoint {
> +                                remote-endpoint = <&dpi0_out0>;
> +                            };
> +                        };
> +                        port@1 {
> +                            reg = <1>;
> +                            oldi0_out: endpoint {
> +                                remote-endpoint = <&panel_in0>;
> +                            };
> +                        };
> +                    };
> +                };
> +                oldi1: oldi@1 {
> +                    reg = <1>;
> +                    clocks = <&k3_clks 186 0>;
> +                    clock-names = "serial";
> +                    ti,secondary-oldi;
> +                    ti,oldi-io-ctrl = <&dss_oldi_io_ctrl>;
> +                    ports {
> +                        #address-cells = <1>;
> +                        #size-cells = <0>;
> +                        port@0 {
> +                            reg = <0>;
> +                            oldi1_in: endpoint {
> +                                remote-endpoint = <&dpi0_out1>;
> +                            };
> +                        };
> +                        port@1 {
> +                            reg = <1>;
> +                            oldi1_out: endpoint {
> +                                remote-endpoint = <&panel_in1>;
> +                            };
> +                        };
> +                    };
> +                };
> +            };
> +            ports {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +                port@0 {
> +                    #address-cells = <1>;
> +                    #size-cells = <0>;
> +                    reg = <0>;
> +                    dpi0_out0: endpoint@0 {
> +                        reg = <0>;
> +                        remote-endpoint = <&oldi0_in>;
> +                    };
> +                    dpi0_out1: endpoint@1 {
> +                        reg = <1>;
> +                        remote-endpoint = <&oldi1_in>;
> +                    };
> +                };
> +                port@1 {
> +                    reg = <1>;
> +                    dpi1_out: endpoint {
> +                        remote-endpoint = <&hdmi_bridge>;
> +                    };
> +                };
> +            };
> +        };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 93415153247b..d47a56c4d276 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7817,6 +7817,7 @@ M:	Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>  L:	dri-devel@lists.freedesktop.org
>  S:	Maintained
>  T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
> +F:	Documentation/devicetree/bindings/display/ti/ti,am625-oldi.yaml
>  F:	Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
>  F:	Documentation/devicetree/bindings/display/ti/ti,j721e-dss.yaml
>  F:	Documentation/devicetree/bindings/display/ti/ti,k2g-dss.yaml
> -- 
> 2.34.1
>