Re: [PATCH v3 1/2] dt-bindings: net: bluetooth: Add MediaTek MT7921S SDIO Bluetooth

[Sean Wang]

Hi Chen-Yu,

On Fri, Apr 12, 2024 at 12:31 AM Chen-Yu Tsai <wenst@xxxxxxxxxxxx> wrote:
>
> The MediaTek MT7921S is a WiFi/Bluetooth combo chip that works over
> SDIO. WiFi and Bluetooth are separate SDIO functions within the chip.
> While the Bluetooth SDIO function is fully discoverable, the chip has
> a pin that can reset just the Bluetooth core, as opposed to the full
> chip. This should be described in the device tree.
>
> Add a device tree binding for the Bluetooth SDIO function of the MT7921S
> specifically to document the reset line. This binding is based on the MMC
> controller binding, which specifies one device node per SDIO function.
>
> Cc: Sean Wang <sean.wang@xxxxxxxxxxxx>
> Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> ---
> Changes since v2:
> - Expand description and commit message to clearly state that WiFi and
>   Bluetooth are separate SDIO functions, and that each function should
>   be a separate device node, as specified by the MMC binding.
> - Change 'additionalProperties' to 'unevaluatedProperties'
> - Add missing separating new line
> - s/ot/to/
>
> Angelo's reviewed-by was not picked up due to the above changes.
>
> Changes since v1:
> - Reworded descriptions
> - Moved binding maintainer section before description
> - Added missing reference to bluetooth-controller.yaml
> - Added missing GPIO header to example
> ---
>  .../bluetooth/mediatek,mt7921s-bluetooth.yaml | 55 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 56 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7921s-bluetooth.yaml
>
> diff --git a/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7921s-bluetooth.yaml b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7921s-bluetooth.yaml
> new file mode 100644
> index 000000000000..67ff7caad599
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7921s-bluetooth.yaml
> @@ -0,0 +1,55 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/net/bluetooth/mediatek,mt7921s-bluetooth.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MediaTek MT7921S Bluetooth
> +
> +maintainers:
> +  - Sean Wang <sean.wang@xxxxxxxxxxxx>
> +
> +description:
> +  MT7921S is an SDIO-attached dual-radio WiFi+Bluetooth Combo chip; each
> +  function is its own SDIO function on a shared SDIO interface. The chip
> +  has two dedicated reset lines, one for each function core.
> +  This binding only covers the Bluetooth SDIO function, with one device
> +  node describing only this SDIO function.
> +
> +allOf:
> +  - $ref: bluetooth-controller.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - mediatek,mt7921s-bluetooth
> +
> +  reg:
> +    const: 2
> +
> +  reset-gpios:
> +    maxItems: 1
> +    description:
> +      An active-low reset line for the Bluetooth core; on typical M.2
> +      key E modules this is the W_DISABLE2# pin.
> +

Thanks for adding the new setup for the MT7921S devices. They look good to me.
Sometimes, the MT7921S might be set up to wake up the host when it's
asleep using a sideband signal.
This might need an extra pin called "wakeup" to make it happen. Can
you help add this pin to the settings in the same update, or should I
do it later?

> +required:
> +  - compatible
> +  - reg
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    mmc {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        bluetooth@2 {
> +            compatible = "mediatek,mt7921s-bluetooth";
> +            reg = <2>;
> +            reset-gpios = <&pio 8 GPIO_ACTIVE_LOW>;
> +        };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 88981d9f3958..218bc2a21207 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13818,6 +13818,7 @@ M:      Sean Wang <sean.wang@xxxxxxxxxxxx>
>  L:     linux-bluetooth@xxxxxxxxxxxxxxx
>  L:     linux-mediatek@xxxxxxxxxxxxxxxxxxx (moderated for non-subscribers)
>  S:     Maintained
> +F:     Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7921s-bluetooth.yaml
>  F:     Documentation/devicetree/bindings/net/mediatek-bluetooth.txt
>  F:     drivers/bluetooth/btmtkuart.c
>
> --
> 2.44.0.683.g7961c838ac-goog
>
>