target/linux/brcm2708/patches-4.19/950-0176-dt-bindings-Document-BCM283x-CSI2-CCP2-receiver.patch

   1 From 8299df54f2016290eed7a2bece3885aad36d13e2 Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.org>
   3 Date: Wed, 31 Oct 2018 14:59:06 +0000
   4 Subject: [PATCH] dt-bindings: Document BCM283x CSI2/CCP2 receiver
   5
   6 Document the DT bindings for the CSI2/CCP2 receiver peripheral
   7 (known as Unicam) on BCM283x SoCs.
   8
   9 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
  10 Acked-by: Rob Herring <robh@kernel.org>
  11 ---
  12  .../bindings/media/bcm2835-unicam.txt         | 85 +++++++++++++++++++
  13  1 file changed, 85 insertions(+)
  14  create mode 100644 Documentation/devicetree/bindings/media/bcm2835-unicam.txt
  15
  16 --- /dev/null
  17 +++ b/Documentation/devicetree/bindings/media/bcm2835-unicam.txt
  18 @@ -0,0 +1,85 @@
  19 +Broadcom BCM283x Camera Interface (Unicam)
  20 +------------------------------------------
  21 +
  22 +The Unicam block on BCM283x SoCs is the receiver for either
  23 +CSI-2 or CCP2 data from image sensors or similar devices.
  24 +
  25 +The main platform using this SoC is the Raspberry Pi family of boards.
  26 +On the Pi the VideoCore firmware can also control this hardware block,
  27 +and driving it from two different processors will cause issues.
  28 +To avoid this, the firmware checks the device tree configuration
  29 +during boot. If it finds device tree nodes called csi0 or csi1 then
  30 +it will stop the firmware accessing the block, and it can then
  31 +safely be used via the device tree binding.
  32 +
  33 +Required properties:
  34 +===================
  35 +- compatible   : must be "brcm,bcm2835-unicam".
  36 +- reg          : physical base address and length of the register sets for the
  37 +                 device.
  38 +- interrupts   : should contain the IRQ line for this Unicam instance.
  39 +- clocks       : list of clock specifiers, corresponding to entries in
  40 +                 clock-names property.
  41 +- clock-names  : must contain an "lp" entry, matching entries in the
  42 +                 clocks property.
  43 +
  44 +Unicam supports a single port node. It should contain one 'port' child node
  45 +with child 'endpoint' node. Please refer to the bindings defined in
  46 +Documentation/devicetree/bindings/media/video-interfaces.txt.
  47 +
  48 +Within the endpoint node the "remote-endpoint" and "data-lanes" properties
  49 +are mandatory.
  50 +Data lane reordering is not supported so the data lanes must be in order,
  51 +starting at 1. The number of data lanes should represent the number of
  52 +usable lanes for the hardware block. That may be limited by either the SoC or
  53 +how the platform presents the interface, and the lower value must be used.
  54 +
  55 +Lane reordering is not supported on the clock lane either, so the optional
  56 +property "clock-lane" will implicitly be <0>.
  57 +Similarly lane inversion is not supported, therefore "lane-polarities" will
  58 +implicitly be <0 0 0 0 0>.
  59 +Neither of these values will be checked.
  60 +
  61 +Example:
  62 +       csi1: csi1@7e801000 {
  63 +               compatible = "brcm,bcm2835-unicam";
  64 +               reg = <0x7e801000 0x800>,
  65 +                     <0x7e802004 0x4>;
  66 +               interrupts = <2 7>;
  67 +               clocks = <&clocks BCM2835_CLOCK_CAM1>;
  68 +               clock-names = "lp";
  69 +
  70 +               port {
  71 +                       csi1_ep: endpoint {
  72 +                               remote-endpoint = <&tc358743_0>;
  73 +                               data-lanes = <1 2>;
  74 +                       };
  75 +               };
  76 +       };
  77 +
  78 +       i2c0: i2c@7e205000 {
  79 +               tc358743: csi-hdmi-bridge@0f {
  80 +                       compatible = "toshiba,tc358743";
  81 +                       reg = <0x0f>;
  82 +
  83 +                       clocks = <&tc358743_clk>;
  84 +                       clock-names = "refclk";
  85 +
  86 +                       tc358743_clk: bridge-clk {
  87 +                               compatible = "fixed-clock";
  88 +                               #clock-cells = <0>;
  89 +                               clock-frequency = <27000000>;
  90 +                       };
  91 +
  92 +                       port {
  93 +                               tc358743_0: endpoint {
  94 +                                       remote-endpoint = <&csi1_ep>;
  95 +                                       clock-lanes = <0>;
  96 +                                       data-lanes = <1 2>;
  97 +                                       clock-noncontinuous;
  98 +                                       link-frequencies =
  99 +                                               /bits/ 64 <297000000>;
 100 +                               };
 101 +                       };
 102 +               };
 103 +       };