On Thu, Feb 08, 2018 at 03:27:32PM +0100, Amelie Delaunay wrote:
> This patch adds documentation of device tree bindings for the
> STMicroelectronics Multi-Function eXpander (MFX).
>
> Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx>
> ---
> Documentation/devicetree/bindings/mfd/st-mfx.txt | 51 ++++++++++++++++++++++++
> 1 file changed, 51 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mfd/st-mfx.txt
>
> diff --git a/Documentation/devicetree/bindings/mfd/st-mfx.txt b/Documentation/devicetree/bindings/mfd/st-mfx.txt
> new file mode 100644
> index 0000000..423d800
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/st-mfx.txt
> @@ -0,0 +1,51 @@
> +STMicroelectronics Multi-Function eXpander
> +
> +ST Multi-Function eXpander (MFX) is a slave controller using I2C for
> +communication with the main MCU. Its main features are gpio expansion, main
> +MCU IDD measurement (IDD is the amount of current that flows through VDD)
> +and resistive touchscreen controller.
You don't have to implement all the drivers now, but please completely
describe the device. As is, there is no reason to have a child GPIO
node.
> +
> +Required properties:
> +- compatible: must be "st,mfx"
Kind of generic. Only 1 single version ever?
> +- reg: I2C address of the device
> +- interrupts: interrupt triggered by MFX_IRQ_OUT signal
> +- interrupt-parent: interrupt controller MFX is connected to
> +- interrupt-controller: marks the device as an interrupt controller
> +- #interrupt-cells: should be <1>, index of the interrupt within the
> + controller, in accordance with the "one cell" variant of
> + <devicetree/bindings/interrupt-controller/interrupt.txt>
> +
> +Optional nodes:
> +
> +* GPIO eXpander
> +MFX provides 16 programmable GPIOs, and it is also possible to recover 8
> +alternate GPIOs if the main functions are not used (touchscreen controller and
> +IDD measurement not enabled).
> +
> +Required properties:
> +- compatible : must be "st,mfx-gpio"
> +- interrupt-parent : must be <&mfx>
Not necessary. A parent node with 'interrupt-controller' property is the
interrupt's parent.
> +- interrupts = must be <0>
> +- gpio-controller: marks the device node as a GPIO controller
> +- #gpio-cells: should be <2>, the first cell is the GPIO offset on this GPIO
> + controller, the second cell is the gpio flags in accordance with
> + <dt-bindings/gpio/st-mfx-gpio.h>.
Custom flags? Use standard flags.
DT binding headers should be part of this patch.
> +
> +Example:
> +
> + mfx: mfx@42 {
> + compatible = "st,mfx";
> + reg = <0x42>;
> + interrupts = <8 IRQ_TYPE_EDGE_RISING>;
> + interrupt-parent = <&gpioi>;
> + interrupt-controller;
> + #interrupt-cells = <1>;
> +
> + mfxgpio: mfx_gpio {
gpio {
> + compatible = "st,mfx-gpio";
> + interrupt-parent = <&mfx>;
> + interrupts = <0>;
> + gpio-controller;
> + #gpio-cells = <2>;
> + };
> + };
> --
> 2.7.4
>
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