Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame^] | 1 | Device-Tree bindings for LVDS Display Bridge (ldb) |
| 2 | |
| 3 | LVDS Display Bridge |
| 4 | =================== |
| 5 | |
| 6 | The LVDS Display Bridge device tree node contains up to two lvds-channel |
| 7 | nodes describing each of the two LVDS encoder channels of the bridge. |
| 8 | |
| 9 | Required properties: |
| 10 | - #address-cells : should be <1> |
| 11 | - #size-cells : should be <0> |
| 12 | - compatible : should be "fsl,imx53-ldb" or "fsl,imx6q-ldb". |
| 13 | Both LDB versions are similar, but i.MX6 has an additional |
| 14 | multiplexer in the front to select any of the four IPU display |
| 15 | interfaces as input for each LVDS channel. |
| 16 | - gpr : should be <&gpr> on i.MX53 and i.MX6q. |
| 17 | The phandle points to the iomuxc-gpr region containing the LVDS |
| 18 | control register. |
| 19 | - clocks, clock-names : phandles to the LDB divider and selector clocks and to |
| 20 | the display interface selector clocks, as described in |
| 21 | Documentation/devicetree/bindings/clock/clock-bindings.txt |
| 22 | The following clocks are expected on i.MX53: |
| 23 | "di0_pll" - LDB LVDS channel 0 mux |
| 24 | "di1_pll" - LDB LVDS channel 1 mux |
| 25 | "di0" - LDB LVDS channel 0 gate |
| 26 | "di1" - LDB LVDS channel 1 gate |
| 27 | "di0_sel" - IPU1 DI0 mux |
| 28 | "di1_sel" - IPU1 DI1 mux |
| 29 | On i.MX6q the following additional clocks are needed: |
| 30 | "di2_sel" - IPU2 DI0 mux |
| 31 | "di3_sel" - IPU2 DI1 mux |
| 32 | The needed clock numbers for each are documented in |
| 33 | Documentation/devicetree/bindings/clock/imx5-clock.yaml, and in |
| 34 | Documentation/devicetree/bindings/clock/imx6q-clock.yaml. |
| 35 | |
| 36 | Optional properties: |
| 37 | - pinctrl-names : should be "default" on i.MX53, not used on i.MX6q |
| 38 | - pinctrl-0 : a phandle pointing to LVDS pin settings on i.MX53, |
| 39 | not used on i.MX6q |
| 40 | - fsl,dual-channel : boolean. if it exists, only LVDS channel 0 should |
| 41 | be configured - one input will be distributed on both outputs in dual |
| 42 | channel mode |
| 43 | |
| 44 | LVDS Channel |
| 45 | ============ |
| 46 | |
| 47 | Each LVDS Channel has to contain either an of graph link to a panel device node |
| 48 | or a display-timings node that describes the video timings for the connected |
| 49 | LVDS display as well as the fsl,data-mapping and fsl,data-width properties. |
| 50 | |
| 51 | Required properties: |
| 52 | - reg : should be <0> or <1> |
| 53 | - port: Input and output port nodes with endpoint definitions as defined in |
| 54 | Documentation/devicetree/bindings/graph.txt. |
| 55 | On i.MX5, the internal two-input-multiplexer is used. Due to hardware |
| 56 | limitations, only one input port (port@[0,1]) can be used for each channel |
| 57 | (lvds-channel@[0,1], respectively). |
| 58 | On i.MX6, there should be four input ports (port@[0-3]) that correspond |
| 59 | to the four LVDS multiplexer inputs. |
| 60 | A single output port (port@2 on i.MX5, port@4 on i.MX6) must be connected |
| 61 | to a panel input port. Optionally, the output port can be left out if |
| 62 | display-timings are used instead. |
| 63 | |
| 64 | Optional properties (required if display-timings are used): |
| 65 | - ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing |
| 66 | - display-timings : A node that describes the display timings as defined in |
| 67 | Documentation/devicetree/bindings/display/panel/display-timing.txt. |
| 68 | - fsl,data-mapping : should be "spwg" or "jeida" |
| 69 | This describes how the color bits are laid out in the |
| 70 | serialized LVDS signal. |
| 71 | - fsl,data-width : should be <18> or <24> |
| 72 | |
| 73 | example: |
| 74 | |
| 75 | gpr: iomuxc-gpr@53fa8000 { |
| 76 | /* ... */ |
| 77 | }; |
| 78 | |
| 79 | ldb: ldb@53fa8008 { |
| 80 | #address-cells = <1>; |
| 81 | #size-cells = <0>; |
| 82 | compatible = "fsl,imx53-ldb"; |
| 83 | gpr = <&gpr>; |
| 84 | clocks = <&clks IMX5_CLK_LDB_DI0_SEL>, |
| 85 | <&clks IMX5_CLK_LDB_DI1_SEL>, |
| 86 | <&clks IMX5_CLK_IPU_DI0_SEL>, |
| 87 | <&clks IMX5_CLK_IPU_DI1_SEL>, |
| 88 | <&clks IMX5_CLK_LDB_DI0_GATE>, |
| 89 | <&clks IMX5_CLK_LDB_DI1_GATE>; |
| 90 | clock-names = "di0_pll", "di1_pll", |
| 91 | "di0_sel", "di1_sel", |
| 92 | "di0", "di1"; |
| 93 | |
| 94 | /* Using an of-graph endpoint link to connect the panel */ |
| 95 | lvds-channel@0 { |
| 96 | #address-cells = <1>; |
| 97 | #size-cells = <0>; |
| 98 | reg = <0>; |
| 99 | |
| 100 | port@0 { |
| 101 | reg = <0>; |
| 102 | |
| 103 | lvds0_in: endpoint { |
| 104 | remote-endpoint = <&ipu_di0_lvds0>; |
| 105 | }; |
| 106 | }; |
| 107 | |
| 108 | port@2 { |
| 109 | reg = <2>; |
| 110 | |
| 111 | lvds0_out: endpoint { |
| 112 | remote-endpoint = <&panel_in>; |
| 113 | }; |
| 114 | }; |
| 115 | }; |
| 116 | |
| 117 | /* Using display-timings and fsl,data-mapping/width instead */ |
| 118 | lvds-channel@1 { |
| 119 | #address-cells = <1>; |
| 120 | #size-cells = <0>; |
| 121 | reg = <1>; |
| 122 | fsl,data-mapping = "spwg"; |
| 123 | fsl,data-width = <24>; |
| 124 | |
| 125 | display-timings { |
| 126 | /* ... */ |
| 127 | }; |
| 128 | |
| 129 | port@1 { |
| 130 | reg = <1>; |
| 131 | |
| 132 | lvds1_in: endpoint { |
| 133 | remote-endpoint = <&ipu_di1_lvds1>; |
| 134 | }; |
| 135 | }; |
| 136 | }; |
| 137 | }; |
| 138 | |
| 139 | panel: lvds-panel { |
| 140 | /* ... */ |
| 141 | |
| 142 | port { |
| 143 | panel_in: endpoint { |
| 144 | remote-endpoint = <&lvds0_out>; |
| 145 | }; |
| 146 | }; |
| 147 | }; |