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104 lines
3.5 KiB
Diff
104 lines
3.5 KiB
Diff
From 8299df54f2016290eed7a2bece3885aad36d13e2 Mon Sep 17 00:00:00 2001
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From: Dave Stevenson <dave.stevenson@raspberrypi.org>
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Date: Wed, 31 Oct 2018 14:59:06 +0000
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Subject: [PATCH] dt-bindings: Document BCM283x CSI2/CCP2 receiver
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Document the DT bindings for the CSI2/CCP2 receiver peripheral
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(known as Unicam) on BCM283x SoCs.
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Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
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Acked-by: Rob Herring <robh@kernel.org>
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---
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.../bindings/media/bcm2835-unicam.txt | 85 +++++++++++++++++++
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1 file changed, 85 insertions(+)
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create mode 100644 Documentation/devicetree/bindings/media/bcm2835-unicam.txt
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--- /dev/null
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+++ b/Documentation/devicetree/bindings/media/bcm2835-unicam.txt
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@@ -0,0 +1,85 @@
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+Broadcom BCM283x Camera Interface (Unicam)
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+------------------------------------------
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+
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+The Unicam block on BCM283x SoCs is the receiver for either
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+CSI-2 or CCP2 data from image sensors or similar devices.
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+
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+The main platform using this SoC is the Raspberry Pi family of boards.
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+On the Pi the VideoCore firmware can also control this hardware block,
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+and driving it from two different processors will cause issues.
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+To avoid this, the firmware checks the device tree configuration
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+during boot. If it finds device tree nodes called csi0 or csi1 then
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+it will stop the firmware accessing the block, and it can then
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+safely be used via the device tree binding.
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+
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+Required properties:
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+===================
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+- compatible : must be "brcm,bcm2835-unicam".
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+- reg : physical base address and length of the register sets for the
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+ device.
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+- interrupts : should contain the IRQ line for this Unicam instance.
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+- clocks : list of clock specifiers, corresponding to entries in
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+ clock-names property.
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+- clock-names : must contain an "lp" entry, matching entries in the
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+ clocks property.
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+
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+Unicam supports a single port node. It should contain one 'port' child node
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+with child 'endpoint' node. Please refer to the bindings defined in
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+Documentation/devicetree/bindings/media/video-interfaces.txt.
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+
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+Within the endpoint node the "remote-endpoint" and "data-lanes" properties
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+are mandatory.
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+Data lane reordering is not supported so the data lanes must be in order,
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+starting at 1. The number of data lanes should represent the number of
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+usable lanes for the hardware block. That may be limited by either the SoC or
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+how the platform presents the interface, and the lower value must be used.
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+
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+Lane reordering is not supported on the clock lane either, so the optional
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+property "clock-lane" will implicitly be <0>.
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+Similarly lane inversion is not supported, therefore "lane-polarities" will
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+implicitly be <0 0 0 0 0>.
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+Neither of these values will be checked.
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+
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+Example:
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+ csi1: csi1@7e801000 {
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+ compatible = "brcm,bcm2835-unicam";
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+ reg = <0x7e801000 0x800>,
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+ <0x7e802004 0x4>;
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+ interrupts = <2 7>;
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+ clocks = <&clocks BCM2835_CLOCK_CAM1>;
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+ clock-names = "lp";
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+
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+ port {
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+ csi1_ep: endpoint {
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+ remote-endpoint = <&tc358743_0>;
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+ data-lanes = <1 2>;
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+ };
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+ };
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+ };
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+
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+ i2c0: i2c@7e205000 {
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+ tc358743: csi-hdmi-bridge@0f {
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+ compatible = "toshiba,tc358743";
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+ reg = <0x0f>;
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+
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+ clocks = <&tc358743_clk>;
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+ clock-names = "refclk";
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+
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+ tc358743_clk: bridge-clk {
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+ compatible = "fixed-clock";
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+ #clock-cells = <0>;
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+ clock-frequency = <27000000>;
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+ };
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+
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+ port {
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+ tc358743_0: endpoint {
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+ remote-endpoint = <&csi1_ep>;
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+ clock-lanes = <0>;
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+ data-lanes = <1 2>;
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+ clock-noncontinuous;
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+ link-frequencies =
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+ /bits/ 64 <297000000>;
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+ };
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+ };
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+ };
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+ };
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