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References: <20240412073046.1192744-1-wenst@chromium.org> <20240412073046.1192744-2-wenst@chromium.org>
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From: Sean Wang <sean.wang@kernel.org>
Date: Wed, 17 Apr 2024 16:04:02 -0700
Message-ID: <CAGp9Lzp=MKNYc70ZeGCAEgWfFVPOAOZQQ86BXukk+EQQM_C+OA@mail.gmail.com>
Subject: Re: [PATCH v3 1/2] dt-bindings: net: bluetooth: Add MediaTek MT7921S
 SDIO Bluetooth
To: Chen-Yu Tsai <wenst@chromium.org>
Cc: Marcel Holtmann <marcel@holtmann.org>, Luiz Augusto von Dentz <luiz.dentz@gmail.com>, 
	Rob Herring <robh+dt@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Matthias Brugger <matthias.bgg@gmail.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>, 
	Sean Wang <sean.wang@mediatek.com>, linux-bluetooth@vger.kernel.org, 
	netdev@vger.kernel.org, linux-mediatek@lists.infradead.org, 
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, 
	linux-kernel@vger.kernel.org
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Hi Chen-Yu,

On Fri, Apr 12, 2024 at 12:31=E2=80=AFAM Chen-Yu Tsai <wenst@chromium.org> =
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@mediatek.com>
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> ---
> 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/media=
tek,mt7921s-bluetooth.yaml
>
> diff --git a/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7=
921s-bluetooth.yaml b/Documentation/devicetree/bindings/net/bluetooth/media=
tek,mt7921s-bluetooth.yaml
> new file mode 100644
> index 000000000000..67ff7caad599
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7921s-bl=
uetooth.yaml
> @@ -0,0 +1,55 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/net/bluetooth/mediatek,mt7921s-blueto=
oth.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MediaTek MT7921S Bluetooth
> +
> +maintainers:
> +  - Sean Wang <sean.wang@mediatek.com>
> +
> +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 =3D <1>;
> +        #size-cells =3D <0>;
> +
> +        bluetooth@2 {
> +            compatible =3D "mediatek,mt7921s-bluetooth";
> +            reg =3D <2>;
> +            reset-gpios =3D <&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@mediatek.com>
>  L:     linux-bluetooth@vger.kernel.org
>  L:     linux-mediatek@lists.infradead.org (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
>
>