Re: [PATCH 2/5] dt-bindings: mfd: Binding for RTL8231

Sander Vanheule
2021-05-19T16:53:26Z

On Mon, 2021-05-17 at 17:38 -0500, Rob Herring wrote:
> On Tue, May 11, 2021 at 02:25:20PM +0200, Sander Vanheule wrote:
> > Add a binding description for the Realtek RTL8231, a GPIO and LED
> > expander chip commonly used in ethernet switches based on a Realtek
> > switch SoC. These chips can be addressed via an MDIO or SMI bus, or used
> > as a plain 36-bit shift register.
> >
> > This binding only describes the feature set provided by the MDIO/SMI
> > configuration, and covers the GPIO, PWM, and pin control properties. The
> > LED properties are defined in a separate binding.
> >
> > Signed-off-by: Sander Vanheule <sander@svanheule.net>
> > ---
> >  .../bindings/mfd/realtek,rtl8231.yaml         | 202 ++++++++++++++++++
> >  1 file changed, 202 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/mfd/realtek,rtl8231.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/mfd/realtek,rtl8231.yaml
> > b/Documentation/devicetree/bindings/mfd/realtek,rtl8231.yaml
> > new file mode 100644
> > index 000000000000..2023cfa887a3
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mfd/realtek,rtl8231.yaml
> > @@ -0,0 +1,202 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/mfd/realtek,rtl8231.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Realtek RTL8231 GPIO and LED expander.
> > +
> > +maintainers:
> > +  - Sander Vanheule <sander@svanheule.net>
> > +
> > +description: |
> > +  The RTL8231 is a GPIO and LED expander chip, providing up to 37 GPIOs, up
> > to
> > +  88 LEDs, and up to one PWM output. This device is frequently used
> > alongside
> > +  Realtek switch SoCs, to provide additional I/O capabilities.
> > +
> > +  To manage the RTL8231's features, its strapping pins can be used to
> > configure
> > +  it in one of three modes: shift register, MDIO device, or SMI device. The
> > +  shift register mode does not need special support. In MDIO or SMI mode,
> > most
> > +  pins can be configured as a GPIO output, LED matrix scan line/column, or
> > as a
> > +  PWM output.
> > +
> > +  The GPIO and pin control are part of the main node. PWM and LED support
> > are
> > +  configured as sub-nodes.
> > +
> > +properties:
> > +  compatible:
> > +    const: realtek,rtl8231
> > +
> > +  reg:
> > +    description: MDIO or SMI device address.
> > +    maxItems: 1
> > +
> > +  # GPIO support
> > +  gpio-controller: true
> > +
> > +  "#gpio-cells":
> > +    const: 2
> > +    description: |
> > +      The first cell is the pin number and the second cell is used to
> > specify
> > +      the gpio active state.
> > +
> > +  gpio-ranges:
> > +    description: |
> > +      Must reference itself, and provide a zero-based mapping for 37 pins.
> > +    maxItems: 1
> > +
> > +  # Pin muxing and configuration
> > +  realtek,drive-strength:
> > +    $ref: /schemas/types.yaml#/definitions/uint32
>
> Use the standard 'drive-strength' property.

Ok, I wasn't sure I could do this, since it's normally used in a pin config, not
a pin controller config. I'll update this, as well as the suggested changes
below.

Best,
Sander

>
> > +    description: |
> > +      Common drive strength used for all GPIO output pins, must be 4mA or
> > 8mA.
> > +      On reset, this value will default to 8mA.
> > +    enum: [4, 8]
> > +
> > +  # LED scanning matrix
> > +  leds:
> > +    $ref: ../leds/realtek,rtl8231-leds.yaml#
> > +
> > +  # PWM output
> > +  pwm:
> > +    type: object
> > +    description: |
> > +      Subnode describing the PWM peripheral. To use the PWM output, gpio35
> > must
> > +      be muxed to its 'pwm' function. Valid frequency values for consumers
> > are
> > +      1200, 1600, 2000, 2400, 2800, 3200, 4000, and 4800.
> > +
> > +    properties:
> > +      "#pwm-cells":
> > +        description: |
> > +          Twos cells with PWM index (must be 0) and PWM frequency in Hz.
> > +        const: 2
> > +
> > +    required:
> > +      - "#pwm-cells"
>
> Just move this to the parent node. No reason for a child node or that 1
> node can't be 2 providers.
>
> > +
> > +patternProperties:
> > +  "-pins$":
> > +    type: object
> > +    $ref: ../pinctrl/pinmux-node.yaml#
> > +
> > +    properties:
> > +      pins:
> > +        items:
> > +          oneOf:
>
> No need for oneOf when there's only 1 entry.
>
> > +            - enum: ["gpio0", "gpio1", "gpio2", "gpio3", "gpio4", "gpio5",
> > "gpio6",
> > +                     "gpio7", "gpio8", "gpio9", "gpio10", "gpio11",
> > "gpio12", "gpio13",
> > +                     "gpio14", "gpio15", "gpio16", "gpio17", "gpio18",
> > "gpio19", "gpio20",
> > +                     "gpio21", "gpio22", "gpio23", "gpio24", "gpio25",
> > "gpio26", "gpio27",
> > +                     "gpio28", "gpio29", "gpio30", "gpio31", "gpio32",
> > "gpio33", "gpio34",
> > +                     "gpio35", "gpio36"]
> > +        minItems: 1
> > +        maxItems: 37
> > +      function:
> > +        description: |
> > +          Select which function to use. "gpio" is supported for all pins,
> > "led" is supported
> > +          for pins 0-34, "pwm" is supported for for pin 35.
> > +        enum: ["gpio", "led", "pwm"]
> > +
> > +    required:
> > +      - pins
> > +      - function
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - gpio-controller
> > +  - "#gpio-cells"
> > +  - gpio-ranges
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    // Minimal example
> > +    mdio {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        expander0: expander@0 {
> > +            compatible = "realtek,rtl8231";
> > +            reg = <0>;
> > +
> > +            gpio-controller;
> > +            #gpio-cells = <2>;
> > +            gpio-ranges = <&expander0 0 0 37>;
> > +        };
> > +    };
> > +  - |
> > +    // All bells and whistles included
> > +    #include <dt-bindings/leds/common.h>
> > +    mdio {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        expander1: expander@1 {
> > +            compatible = "realtek,rtl8231";
> > +            reg = <1>;
> > +
> > +            gpio-controller;
> > +            #gpio-cells = <2>;
> > +            gpio-ranges = <&expander1 0 0 37>;
> > +
> > +            realtek,drive-strength = <4>;
> > +
> > +            button-pins {
> > +                pins = "gpio36";
> > +                function = "gpio";
> > +                input-debounce = "100000";
> > +            };
> > +
> > +            pwm-pins {
> > +                pins = "gpio35";
> > +                function = "pwm";
> > +            };
> > +
> > +            led-pins {
> > +                pins = "gpio0", "gpio1", "gpio3", "gpio4";
> > +                function = "led";
> > +            };
> > +
> > +            pwm {
> > +                #pwm-cells = <2>;
> > +            };
> > +
> > +            leds {
> > +                compatible = "realtek,rtl8231-leds";
> > +                #address-cells = <2>;
> > +                #size-cells = <0>;
> > +
> > +                realtek,led-scan-mode = "single-color";
> > +
> > +                led@0,0 {
> > +                    reg = <0 0>;
> > +                    color = <LED_COLOR_ID_GREEN>;
> > +                    function = LED_FUNCTION_LAN;
> > +                    function-enumerator = <0>;
> > +                };
> > +
> > +                led@0,1 {
> > +                    reg = <0 1>;
> > +                    color = <LED_COLOR_ID_AMBER>;
> > +                    function = LED_FUNCTION_LAN;
> > +                    function-enumerator = <0>;
> > +                };
> > +
> > +                led@1,0 {
> > +                    reg = <1 0>;
> > +                    color = <LED_COLOR_ID_GREEN>;
> > +                    function = LED_FUNCTION_LAN;
> > +                    function-enumerator = <1>;
> > +                };
> > +
> > +                led@1,1 {
> > +                    reg = <1 1>;
> > +                    color = <LED_COLOR_ID_AMBER>;
> > +                    function = LED_FUNCTION_LAN;
> > +                    function-enumerator = <1>;
> > +                };
> > +            };
> > +        };
> > +    };
> > --
> > 2.31.1
> >