Commit 6f633bc9 authored by Jonathan Cameron's avatar Jonathan Cameron
Browse files

dt-bindings:iio:afe:voltage-divider: txt to yaml conversion 



Simple binding so straight forward conversion, though did require
adding a separate binding document for the max1027 to reflect
its abilities to provide channels to consumers.

Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Cc: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20201031181242.742301-9-jic23@kernel.org
parent bd690dfa

Documentation/devicetree/bindings/iio/afe/voltage-divider.txt

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Voltage divider

===============



When an io-channel measures the midpoint of a voltage divider, the

interesting voltage is often the voltage over the full resistance

of the divider. This binding describes the voltage divider in such

a curcuit.



    Vin ----.

            |

         .-----.

         |  R  |

         '-----'

            |

            +---- Vout

            |

         .-----.

         | Rout|

         '-----'

            |

           GND



Required properties:

- compatible : "voltage-divider"

- io-channels : Channel node of a voltage io-channel measuring Vout.

- output-ohms : Resistance Rout over which the output voltage is measured.

	        See full-ohms.

- full-ohms : Resistance R + Rout for the full divider. The io-channel

	      is scaled by the Rout / (R + Rout) quotient.



Example:

The system voltage is circa 12V, but divided down with a 22/222

voltage divider (R = 200 Ohms, Rout = 22 Ohms) and fed to an ADC.



sysv {

	compatible = "voltage-divider";

	io-channels = <&maxadc 1>;



	/* Scale the system voltage by 22/222 to fit the ADC range. */

	output-ohms = <22>;

	full-ohms = <222>; /* 200 + 22 */

};



&spi {

	maxadc: adc@0 {

		compatible = "maxim,max1027";

		reg = <0>;

		#io-channel-cells = <1>;

		interrupt-parent = <&gpio5>;

		interrupts = <15 IRQ_TYPE_EDGE_RISING>;

		spi-max-frequency = <1000000>;

	};

};

Documentation/devicetree/bindings/iio/afe/voltage-divider.yaml

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# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)

%YAML 1.2

---

$id: http://devicetree.org/schemas/iio/afe/voltage-divider.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#



title: Voltage divider



maintainers:

  - Peter Rosin <peda@axentia.se>



description: |

  When an io-channel measures the midpoint of a voltage divider, the

  interesting voltage is often the voltage over the full resistance

  of the divider. This binding describes the voltage divider in such

  a curcuit.



    Vin ----.

            |

         .-----.

         |  R  |

         '-----'

            |

            +---- Vout

            |

         .-----.

         | Rout|

         '-----'

            |

           GND





properties:

  compatible:

    const: voltage-divider



  io-channels:

    maxItems: 1

    description: |

      Channel node of a voltage io-channel.



  output-ohms:

    description:

      Resistance Rout over which the output voltage is measured. See full-ohms.



  full-ohms:

    description:

      Resistance R + Rout for the full divider. The io-channel is scaled by

      the Rout / (R + Rout) quotient.



required:

  - compatible

  - io-channels

  - output-ohms

  - full-ohms



additionalProperties: false



examples:

  - |

    #include <dt-bindings/interrupt-controller/irq.h>

    /*

     * The system voltage is circa 12V, but divided down with a 22/222

     * voltage divider (R = 200 Ohms, Rout = 22 Ohms) and fed to an ADC.

     */

    spi {

        #address-cells = <1>;

        #size-cells = <0>;

        maxadc: adc@0 {

            compatible = "maxim,max1027";

            reg = <0>;

            #io-channel-cells = <1>;

            interrupt-parent = <&gpio5>;

            interrupts = <15 IRQ_TYPE_EDGE_RISING>;

            spi-max-frequency = <1000000>;

        };

    };

    sysv {

        compatible = "voltage-divider";

        io-channels = <&maxadc 1>;



        /* Scale the system voltage by 22/222 to fit the ADC range. */

        output-ohms = <22>;

        full-ohms = <222>; /* 200 + 22 */

    };

...