[RFC PATCH 1/6] dt-bindings: display: imx: Add EPDC

Andreas Kemnade
2022-02-06T08:20:53Z

Add a binding for the Electrophoretic Display Controller found at least
in the i.MX6.
The timing subnode is directly here to avoid having display parameters
spread all over the plate.

Supplies are organized the same way as in the fbdev driver in the
NXP/Freescale kernel forks. The regulators used for that purpose,
like the TPS65185, the SY7636A and MAX17135 have typically a single bit to
start a bunch of regulators of higher or negative voltage with a
well-defined timing. VCOM can be handled separately, but can also be
incorporated into that single bit.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
.../bindings/display/imx/fsl,mxc-epdc.yaml | 159 ++++++++++++++++++
1 file changed, 159 insertions(+)
create mode 100644 Documentation/devicetree/bindings/display/imx/fsl,mxc-epdc.yaml

diff --git a/Documentation/devicetree/bindings/display/imx/fsl,mxc-epdc.yaml b/Documentation/devicetree/bindings/display/imx/fsl,mxc-epdc.yaml
new file mode 100644
index 000000000000..7e0795cc3f70
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/imx/fsl,mxc-epdc.yaml
@@ -0,0 +1,159 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/imx/fsl,mxc-epdc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale i.MX6 EPDC
+
+maintainers:
+ - Andreas Kemnade <andreas@kemnade.info>
+
+description: |
+ The EPDC is a controller for handling electronic paper displays found in
+ i.MX6 SoCs.
+
+properties:
+ compatible:
+ enum:
+ - fsl,imx6sl-epdc
+ - fsl,imx6sll-epdc
+
+ reg:
+ maxItems: 1
+
+ clocks:
+ items:
+ - description: Bus clock
+ - description: Pixel clock
+
+ clock-names:
+ items:
+ - const: axi
+ - const: pix
+
+ interrupts:
+ maxItems: 1
+
+ vscan-holdoff:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ sdoed-width:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ sdoed-delay:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ sdoez-width:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ sdoez-delay:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ gdclk-hp-offs:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ gdsp-offs:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ gdoe-offs:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ gdclk-offs:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ num-ce:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maxItems: 1
+
+ timing:
+ $ref: /display/panel/panel-timing.yaml#
+
+ DISPLAY-supply:
+ description:
+ A couple of +/- voltages automatically powered on in a defintive order
+
+ VCOM-supply:
+ description: compensation voltage
+
+ V3P3-supply:
+ description: V3P3 supply
+
+ epd-thermal-zone:
+ description:
+ Zone to get temperature of the EPD from, practically ambient temperature.
+
+
+
+required:
+ - compatible
+ - reg
+ - clocks
+ - clock-names
+ - interrupts
+ - vscan-holdoff
+ - sdoed-width
+ - sdoed-delay
+ - sdoez-width
+ - sdoez-delay
+ - gdclk-hp-offs
+ - gdsp-offs
+ - gdoe-offs
+ - gdclk-offs
+ - num-ce
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/clock/imx6sl-clock.h>
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+ epdc: epdc@20f4000 {
+ compatible = "fsl,imx6sl-epdc";
+ reg = <0x020f4000 0x4000>;
+ interrupts = <0 97 IRQ_TYPE_LEVEL_HIGH>;
+ clocks = <&clks IMX6SL_CLK_EPDC_AXI>, <&clks IMX6SL_CLK_EPDC_PIX>;
+ clock-names = "axi", "pix";
+
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_epdc0>;
+ V3P3-supply = <&V3P3_reg>;
+ VCOM-supply = <&VCOM_reg>;
+ DISPLAY-supply = <&DISPLAY_reg>;
+ epd-thermal-zone = "epd-thermal";
+
+ vscan-holdoff = <4>;
+ sdoed-width = <10>;
+ sdoed-delay = <20>;
+ sdoez-width = <10>;
+ sdoez-delay = <20>;
+ gdclk-hp-offs = <562>;
+ gdsp-offs = <662>;
+ gdoe-offs = <0>;
+ gdclk-offs = <225>;
+ num-ce = <3>;
+ status = "okay";
+
+ timing {
+ clock-frequency = <80000000>;
+ hactive = <1448>;
+ hback-porch = <16>;
+ hfront-porch = <102>;
+ hsync-len = <28>;
+ vactive = <1072>;
+ vback-porch = <4>;
+ vfront-porch = <4>;
+ vsync-len = <2>;
+ };
+ };
+...
--
2.30.2