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Subject[PATCH v2 3/3] dt-bindings: bus: Add Freescale i.MX8qxp pixel link MSI bus binding
Date
Freescale i.MX8qxp pixel link MSI bus is a simple memory-mapped bus.
It is used to access peripherals in i.MX8qm/qxp imaging, LVDS, MIPI
DSI and HDMI TX subsystems, like I2C controller, PWM controller,
MIPI DSI controller and Control and Status Registers (CSR) module.

Reference simple-pm-bus bindings and add Freescale i.MX8qxp pixel
link MSI bus specific bindings.

Signed-off-by: Liu Ying <victor.liu@nxp.com>
---
v1->v2:
Address Krzysztof's comments:
* Add a select to explicitly select the MSI bus dt-binding.
* List 'simple-pm-bus' explicitly as one item of compatible strings.
* Require compatible and reg properties.
* Put reg property just after compatible property in example.

.../bus/fsl,imx8qxp-pixel-link-msi-bus.yaml | 97 +++++++++++++++++++
1 file changed, 97 insertions(+)
create mode 100644 Documentation/devicetree/bindings/bus/fsl,imx8qxp-pixel-link-msi-bus.yaml

diff --git a/Documentation/devicetree/bindings/bus/fsl,imx8qxp-pixel-link-msi-bus.yaml b/Documentation/devicetree/bindings/bus/fsl,imx8qxp-pixel-link-msi-bus.yaml
new file mode 100644
index 000000000000..358c032041e5
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/fsl,imx8qxp-pixel-link-msi-bus.yaml
@@ -0,0 +1,97 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/bus/fsl,imx8qxp-pixel-link-msi-bus.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale i.MX8qxp Pixel Link Medium Speed Interconnect (MSI) Bus
+
+maintainers:
+ - Liu Ying <victor.liu@nxp.com>
+
+description: |
+ i.MX8qxp pixel link MSI bus is used to control settings of PHYs, I/Os
+ sitting together with the PHYs. It is not the same as the MSI bus coming
+ from i.MX8 System Controller Unit (SCU) which is used to control power,
+ clock and reset through the i.MX8 Distributed Slave System Controller (DSC).
+
+ i.MX8qxp pixel link MSI bus is a simple memory-mapped bus. Two input clocks,
+ that is, MSI clock and AHB clock, need to be enabled so that peripherals
+ connected to the bus can be accessed. Also, the bus is part of a power
+ domain. The power domain needs to be enabled before the peripherals can
+ be accessed.
+
+ Peripherals in i.MX8qm/qxp imaging, LVDS, MIPI DSI and HDMI TX subsystems,
+ like I2C controller, PWM controller, MIPI DSI controller and Control and
+ Status Registers (CSR) module, are accessed through the bus.
+
+ The i.MX System Controller Firmware (SCFW) owns and uses the i.MX8qm/qxp
+ pixel link MSI bus controller and does not allow SCFW user to control it.
+ So, the controller's registers cannot be accessed by SCFW user. Hence,
+ the interrupts generated by the controller don't make any sense from SCFW
+ user's point of view.
+
+allOf:
+ - $ref: simple-pm-bus.yaml#
+
+# We need a select here so we don't match all nodes with 'simple-pm-bus'.
+select:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - fsl,imx8qxp-display-pixel-link-msi-bus
+ - fsl,imx8qm-display-pixel-link-msi-bus
+ required:
+ - compatible
+
+properties:
+ compatible:
+ items:
+ - enum:
+ - fsl,imx8qxp-display-pixel-link-msi-bus
+ - fsl,imx8qm-display-pixel-link-msi-bus
+ - const: simple-pm-bus
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ clocks:
+ items:
+ - description: master gated clock from system
+ - description: AHB clock
+
+ clock-names:
+ items:
+ - const: msi
+ - const: ahb
+
+required:
+ - compatible
+ - reg
+ - clocks
+ - clock-names
+ - power-domains
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/clock/imx8-lpcg.h>
+ #include <dt-bindings/firmware/imx/rsrc.h>
+ bus@56200000 {
+ compatible = "fsl,imx8qxp-display-pixel-link-msi-bus", "simple-pm-bus";
+ reg = <0x56200000 0x20000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ interrupt-parent = <&dc0_irqsteer>;
+ interrupts = <320>;
+ ranges;
+ clocks = <&dc0_disp_ctrl_link_mst0_lpcg IMX_LPCG_CLK_4>,
+ <&dc0_disp_ctrl_link_mst0_lpcg IMX_LPCG_CLK_4>;
+ clock-names = "msi", "ahb";
+ power-domains = <&pd IMX_SC_R_DC_0>;
+ };
--
2.25.1
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