Hi Tomi, Thank you for reviewing the patches! On 11/02/25 17:54, Tomi Valkeinen wrote: > Hi, > > On 09/02/2025 18:09, Aradhya Bhatia wrote: >> From: Aradhya Bhatia <a-bhatia1@xxxxxx> >> >> 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@xxxxxx> >> Signed-off-by: Aradhya Bhatia <aradhya.bhatia@xxxxxxxxx> >> --- >> .../bindings/display/ti/ti,am625-oldi.yaml | 88 ++++++++++ >> .../bindings/display/ti/ti,am65x-dss.yaml | 154 ++++++++++++++++++ >> MAINTAINERS | 1 + >> 3 files changed, 243 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..42a80a512660 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/display/ti/ti,am625-oldi.yaml >> @@ -0,0 +1,88 @@ >> +# 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@xxxxxxxxxxxxxxxx> >> + - Aradhya Bhatia <aradhya.bhatia@xxxxxxxxx> >> + >> +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. > > I think these work, but I'm wondering if we would ever need to check > something from the main oldi from the secondary oldi. In that case > "crossed phandles" would be better, i.e. something like: > > (in the first oldi:) > ti,slave-oldi = <phandle-to-second-oldi> > > (in the second oldi:) > ti,master-oldi = <phandle-to-first-oldi> When I had first designed the code and the devicetree for OLDI, it was done so with the belief that we wouldn't reqiure a bridge instance for the secondary OLDI, at all. While that idea holds true for dual-lvds configuration, it doesn't so for the clone mode configuration. For clone mode, as you pointed out, we will require a 2nd bridge instance to configure any of the bridges and panels that come after the 2nd OLDI. > > Then again, if we ever need that, even with these bindings the driver > could find the first oldi, but needs to go via the dss's node. While it is possible to do it this way, it might not be the cleanest one. And _if_ there is a ever a DSS in future with more than 2 OLDI TXes, say 4, then the decipher logic may get too complicated. While I cannot think of any case where the secondary OLDI bridge DT might need to access the primary OLDI bridge at the moment, I wonder if we should play it safer and have this option anyway. Maybe something like this? (primary OLDI) ti,primary-oldi; ti,companion-oldi = <phandle-to-secondary-oldi>; (secondary OLDI) ti,secondary-oldi; ti,companion-oldi = <phandle-to-primary-oldi>; I will have to drop the condition below, and add ti,primary-oldi property. > > So, just a thought. > > Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx> > > >> + 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 >> + (this condition) >> +required: >> + - reg >> + - clocks >> + - clock-names >> + - ti,oldi-io-ctrl >> + - ports >> + >> +additionalProperties: false >> + >> +... >> diff --git a/Documentation/devicetree/bindings/display/ti/ti,am65x- >> dss.yaml b/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml >> index 399d68986326..a82c525631ea 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: >> $ref: /schemas/graph.yaml#/properties/port >> @@ -112,6 +130,25 @@ properties: >> Input memory (from main memory to dispc) bandwidth limit in >> bytes per second >> + oldi-transmitters: >> + description: >> + Child node under the DSS, to describe all the OLDI transmitters >> connected >> + to the DSS videoports. >> + type: object >> + additionalProperties: false >> + >> + properties: >> + "#address-cells": >> + const: 1 >> + >> + "#size-cells": >> + const: 0 >> + >> + patternProperties: >> + '^oldi@[0-1]$': >> + $ref: ti,am625-oldi.yaml# >> + description: OLDI transmitters connected to the DSS VPs >> + >> allOf: >> - if: >> properties: >> @@ -120,10 +157,25 @@ allOf: >> const: ti,am62a7-dss >> then: >> properties: >> + oldi-transmitters: false >> ports: >> properties: >> port@0: false >> + - if: >> + properties: >> + compatible: >> + contains: >> + const: ti,am65x-dss >> + then: >> + properties: >> + oldi-transmitters: false >> + ports: >> + properties: >> + port@0: >> + properties: >> + endpoint@1: false >> + >> required: >> - compatible >> - reg >> @@ -171,3 +223,105 @@ 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 0fa7c5728f1e..88fa2d9435b8 100644 >> --- a/MAINTAINERS >> +++ b/MAINTAINERS >> @@ -7816,6 +7816,7 @@ M: Tomi Valkeinen >> <tomi.valkeinen@xxxxxxxxxxxxxxxx> >> L: dri-devel@xxxxxxxxxxxxxxxxxxxxx >> 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 > -- Regards Aradhya
