Documentation/devicetree/bindings/power/rockchip-io-domain.yaml

Source file repositories/reference/linux-study-clean/Documentation/devicetree/bindings/power/rockchip-io-domain.yaml

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Linux kernel
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Documentation/devicetree/bindings/power/rockchip-io-domain.yaml
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.yaml
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415
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Support Tooling And Documentation
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Documentation
Inferred role
Support Tooling And Documentation: configuration, schema, or hardware description
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atlas-only

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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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# SPDX-License-Identifier: GPL-2.0
%YAML 1.2
---
$id: http://devicetree.org/schemas/power/rockchip-io-domain.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Rockchip SRAM for IO Voltage Domains

maintainers:
  - Heiko Stuebner <heiko@sntech.de>

description: |
  IO domain voltages on some Rockchip SoCs are variable but need to be
  kept in sync between the regulators and the SoC using a special
  register.

  A specific example using rk3288
    If the regulator hooked up to a pin like SDMMC0_VDD is 3.3V then
    bit 7 of GRF_IO_VSEL needs to be 0. If the regulator hooked up to
    that same pin is 1.8V then bit 7 of GRF_IO_VSEL needs to be 1.

  Said another way, this driver simply handles keeping bits in the SoCs
  General Register File (GRF) in sync with the actual value of a voltage
  hooked up to the pins.

  Note that this driver specifically does not include
    any logic for deciding what voltage we should set regulators to
    any logic for deciding whether regulators (or internal SoC blocks)
    should have power or not have power

  If there were some other software that had the smarts of making
  decisions about regulators, it would work in conjunction with this
  driver. When that other software adjusted a regulators voltage then
  this driver would handle telling the SoC about it. A good example is
  vqmmc for SD. In that case the dw_mmc driver simply is told about a
  regulator. It changes the regulator between 3.3V and 1.8V at the
  right time. This driver notices the change and makes sure that the
  SoC is on the same page.

  You specify supplies using the standard regulator bindings by including
  a phandle the relevant regulator. All specified supplies must be able
  to report their voltage. The IO Voltage Domain for any non-specified
  supplies will be not be touched.

properties:
  compatible:
    enum:
      - rockchip,px30-io-voltage-domain
      - rockchip,px30-pmu-io-voltage-domain
      - rockchip,rk3188-io-voltage-domain
      - rockchip,rk3228-io-voltage-domain
      - rockchip,rk3288-io-voltage-domain
      - rockchip,rk3308-io-voltage-domain
      - rockchip,rk3328-io-voltage-domain
      - rockchip,rk3368-io-voltage-domain
      - rockchip,rk3368-pmu-io-voltage-domain
      - rockchip,rk3399-io-voltage-domain
      - rockchip,rk3399-pmu-io-voltage-domain
      - rockchip,rk3568-pmu-io-voltage-domain
      - rockchip,rv1108-io-voltage-domain
      - rockchip,rv1108-pmu-io-voltage-domain
      - rockchip,rv1126-pmu-io-voltage-domain

required:
  - compatible

unevaluatedProperties: false

allOf:
  - $ref: "#/$defs/px30"

Annotation

Implementation Notes