Re: [PATCH v5 3/6] dt-bindings: input: Document Microsoft G6 Touch Digitizer

Rob Herring
2022-07-11T22:43:59Z

On Thu, Jul 07, 2022 at 09:58:59AM -0700, Jarrett Schultz wrote:
> From: Jarrett Schultz <jaschultz@microsoft.com>
>
> Documentation describes the required and optional properties for
> implementing Device Tree for a Microsoft G6 Touch Digitizer that
> supports HID over SPI Protocol 1.0 specification.
>
> Signed-off-by: Dmitry Antipov <dmanti@microsoft.com>
> Signed-off-by: Jarrett Schultz <jaschultz@microsoft.com>
> ---
> .../input/microsoft,g6-touch-digitizer.yaml | 135 ++++++++++++++++++
> 1 file changed, 135 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/input/microsoft,g6-touch-digitizer.yaml
>
> diff --git a/Documentation/devicetree/bindings/input/microsoft,g6-touch-digitizer.yaml b/Documentation/devicetree/bindings/input/microsoft,g6-touch-digitizer.yaml
> new file mode 100644
> index 000000000000..b607bbb32a42
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/microsoft,g6-touch-digitizer.yaml
> @@ -0,0 +1,135 @@
> +# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/input/microsoft,g6-touch-digitizer.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microsoft G6 Touch Digitizer
> +
> +maintainers:
> + - Dmitry Antipov <dmanti@microsoft.com>
> +
> +description: |
> + Microsoft G6 touch digitizer is a HID over SPI device supporting HID Over SPI
> + Protocol Specification 1.0, available at
> + https://www.microsoft.com/en-us/download/details.aspx?id=103325.
> +
> +properties:
> + compatible:
> + items:
> + - const: microsoft,g6-touch-digitizer
> +
> + reg:
> + maxItems: 1
> +
> + interrupts:
> + maxItems: 1
> +
> + reset-gpios:
> + maxItems: 1
> + description:
> + GPIO specifier for the digitizer's reset pin (active low). The line must
> + be flagged with GPIO_ACTIVE_LOW.
> +
> + vdd-supply:
> + description:
> + Regulator for the VDD supply voltage.
> +
> + input-report-header-address:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + minimum: 0
> + maximum: 16777215

0xffffff would be more readable IMO.

> + description:
> + A value to be included in the Read Approval packet, listing an address of
> + the input report header to be put on the SPI bus. This address has 24
> + bits.
> +
> + input-report-body-address:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + minimum: 0
> + maximum: 16777215
> + description:
> + A value to be included in the Read Approval packet, listing an address of
> + the input report body to be put on the SPI bus. This address has 24 bits.
> +
> + output-report-address:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + minimum: 0
> + maximum: 16777215
> + description:
> + A value to be included in the Output Report sent by the host, listing an
> + address where the output report on the SPI bus is to be written to. This
> + address has 24 bits.

Are all these properties common to HID-over-SPI or all of HID? If so,
then they should be in a common, shared schema doc and referenced here.

> +
> + post-power-on-delay-ms:
> + description:
> + Optional time in ms required by the device after enabling its regulators
> + or powering it on, before it is ready for communication.
> +
> + minimal-reset-delay-ms:
> + description:
> + Optional minimum amount of time in ms that device needs to be in reset
> + state for the reset to take effect.

These delays should really be implied by the compatible string.

> +
> + read-opcode:
> + description:
> + Value to be used in Read Approval packets. 1 byte.

Needs a type reference.

> +
> + write-opcode:
> + description:
> + Value to be used in Write Approval packets. 1 byte.

ditto

> +
> + hid-over-spi-flags:
> + description:
> + 16 bits.
> + Bits 0-12 - Reserved (must be 0)
> + Bit 13 - SPI Write Mode. Possible values -
> + * 0b0- Writes are carried out in Single-SPI mode
> + * 0b1- Writes are carried out in the Multi-SPI mode specified by bits
> + 14-15
> + Bits 14-15 - Multi-SPI Mode. Possible values -
> + * 0b00- Single SPI
> + * 0b01- Dual SPI
> + * 0b10- Quad SPI

ditto.

The existing SPI bus width properties wouldn't work here?

> +
> +required:
> + - compatible
> + - interrupts
> + - reset-gpios
> + - vdd-supply
> + - input-report-header-address
> + - input-report-body-address
> + - output-report-address
> + - read-opcode
> + - write-opcode
> + - hid-over-spi-flags
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/interrupt-controller/irq.h>
> + #include <dt-bindings/gpio/gpio.h>
> +
> + spi {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + hid@0 {
> + compatible = "microsoft,g6-touch-digitizer";
> + reg = <0x0>;
> + interrupts-extended = <&gpio 42 IRQ_TYPE_EDGE_FALLING>;
> + reset-gpios = <&gpio 27 GPIO_ACTIVE_LOW>;
> + vdd-supply = <&pm8350c_l3>;
> + pinctrl-names = "default";
> + pinctrl-0 = <&ts_d6_reset_assert &ts_d6_int_bias>;
> + input-report-header-address = <0x1000>;
> + input-report-body-address = <0x1004>;
> + output-report-address = <0x2000>;
> + read-opcode = <0x0b>;
> + write-opcode = <0x02>;

Description says 8-bit, but this is 32-bits.

> + hid-over-spi-flags = <0x00>;

Description says 16-bits, but this is 32-bits.

> + post-power-on-delay-ms = <5>;
> + minimal-reset-delay-ms = <5>;
> + };
> + };
> --
> 2.25.1
>
>