cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

i2c-mux-gpio.yaml (3152B)

      1# SPDX-License-Identifier: GPL-2.0-only
      2%YAML 1.2
      3---
      4$id: http://devicetree.org/schemas/i2c/i2c-mux-gpio.yaml#
      5$schema: http://devicetree.org/meta-schemas/core.yaml#
      6
      7title: GPIO-based I2C Bus Mux
      8
      9maintainers:
     10  - Wolfram Sang <wsa@kernel.org>
     11
     12description: |
     13  This binding describes an I2C bus multiplexer that uses GPIOs to route the I2C signals.
     14
     15                                  +-----+  +-----+
     16                                  | dev |  | dev |
     17    +------------+                +-----+  +-----+
     18    | SoC        |                   |        |
     19    |            |          /--------+--------+
     20    |   +------+ |  +------+    child bus A, on GPIO value set to 0
     21    |   | I2C  |-|--| Mux  |
     22    |   +------+ |  +--+---+    child bus B, on GPIO value set to 1
     23    |            |     |    \----------+--------+--------+
     24    |   +------+ |     |               |        |        |
     25    |   | GPIO |-|-----+            +-----+  +-----+  +-----+
     26    |   +------+ |                  | dev |  | dev |  | dev |
     27    +------------+                  +-----+  +-----+  +-----+
     28
     29  For each I2C child node, an I2C child bus will be created. They will be numbered based on their
     30  order in the device tree.
     31
     32  Whenever an access is made to a device on a child bus, the value set in the relevant node's reg
     33  property will be output using the list of GPIOs, the first in the list holding the least-
     34  significant value.
     35
     36  If an idle state is defined, using the idle-state (optional) property, whenever an access is not
     37  being made to a device on a child bus, the GPIOs will be set according to the idle value.
     38
     39  If an idle state is not defined, the most recently used value will be left programmed into
     40  hardware whenever no access is being made to a device on a child bus.
     41
     42properties:
     43  compatible:
     44    const: i2c-mux-gpio
     45
     46  i2c-parent:
     47    description: phandle of the I2C bus that this multiplexer's master-side port is connected to
     48    $ref: "/schemas/types.yaml#/definitions/phandle"
     49
     50  mux-gpios:
     51    description: list of GPIOs used to control the muxer
     52    minItems: 1
     53    maxItems: 4  # Should be enough
     54
     55  idle-state:
     56    description: Value to set the muxer to when idle. When no value is given, it defaults to the
     57      last value used.
     58    $ref: "/schemas/types.yaml#/definitions/uint32"
     59
     60allOf:
     61  - $ref: i2c-mux.yaml
     62
     63unevaluatedProperties: false
     64
     65required:
     66  - compatible
     67  - i2c-parent
     68  - mux-gpios
     69
     70examples:
     71  - |
     72    i2cmux {
     73      compatible = "i2c-mux-gpio";
     74      #address-cells = <1>;
     75      #size-cells = <0>;
     76      mux-gpios = <&gpio1 22 0>, <&gpio1 23 0>;
     77      i2c-parent = <&i2c1>;
     78
     79      i2c@1 {
     80        reg = <1>;
     81        #address-cells = <1>;
     82        #size-cells = <0>;
     83
     84        ssd1307: oled@3c {
     85          compatible = "solomon,ssd1307fb-i2c";
     86          reg = <0x3c>;
     87          pwms = <&pwm 4 3000>;
     88          reset-gpios = <&gpio2 7 1>;
     89        };
     90      };
     91
     92      i2c@3 {
     93        reg = <3>;
     94        #address-cells = <1>;
     95        #size-cells = <0>;
     96
     97        pca9555: pca9555@20 {
     98          compatible = "nxp,pca9555";
     99          gpio-controller;
    100          #gpio-cells = <2>;
    101          reg = <0x20>;
    102        };
    103      };
    104    };