[PATCH v3 2/4] dt-bindings: display: ti: Add schema for AM625 OLDI Transmitter

Aradhya Bhatia
2024-07-16T08:43:21Z

The OLDI (transmitters) TXes do not have registers of their own, and are
dependent on the source video-ports 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 OLDI functionality is further supported by a system-control module,
which contains a few registers to control OLDI IO power and
characteristics.

Add devicetree binding schema for AM625 OLDI TXes.

Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
---
.../bindings/display/ti/ti,am625-oldi.yaml | 153 ++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 154 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..0a96e600bc0b
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/ti/ti,am625-oldi.yaml
@@ -0,0 +1,153 @@
+# 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 <a-bhatia1@ti.com>
+
+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: s_clk
+
+ 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 an OLDI TX as secondary node.
+
+ 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. This property is needed for OLDI interface to work.
+
+ 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:
+ properties:
+ ti,secondary-oldi: true
+ then:
+ properties:
+ ti,companion-oldi: false
+ ti,oldi-io-ctrl: false
+ clocks: false
+ clock-names: false
+
+ else:
+ required:
+ - ti,oldi-io-ctrl
+ - clocks
+ - clock-names
+
+required:
+ - reg
+ - ports
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/soc/ti,sci_pm_domain.h>
+
+ oldi_txes {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ oldi: oldi@0 {
+ reg = <0>;
+ clocks = <&k3_clks 186 0>;
+ clock-names = "s_clk";
+ ti,oldi-io-ctrl = <&dss_oldi_io_ctrl>;
+ ports {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ port@0 {
+ reg = <0>;
+ oldi_in: endpoint {
+ remote-endpoint = <&dpi0_out>;
+ };
+ };
+ };
+ };
+ };
+
+ - |
+ #include <dt-bindings/soc/ti,sci_pm_domain.h>
+
+ oldi_txes {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ oldi0: oldi@0 {
+ reg = <0>;
+ clocks = <&k3_clks 186 0>;
+ clock-names = "s_clk";
+ 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>;
+ };
+ };
+ };
+ };
+ oldi1: oldi@1 {
+ reg = <1>;
+ ti,secondary-oldi;
+ ports {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ port@0 {
+ reg = <0>;
+ oldi1_in: endpoint {
+ remote-endpoint = <&dpi0_out1>;
+ };
+ };
+ };
+ };
+ };
+
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index fb1df8c29f5a..26b1dd3367c5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7642,6 +7642,7 @@ 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