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

[AngeloGioacchino Del Regno]

Il 26/01/24 04:26, Chen-Yu Tsai ha scritto:
> On Thu, Jan 25, 2024 at 7:39 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:
> > Il 25/01/24 10:52, Chen-Yu Tsai ha scritto:
> > > The MediaTek MT7921S is a WiFi/Bluetooth combo chip that works over
> > > SDIO. While the Bluetooth function is fully discoverable, the chip
> > > has a pin that can reset just the Bluetooth side, as opposed to the
> > > full chip. This needs to be described in the device tree.
> > >
> > > Add a device tree binding for MT7921S Bluetooth over SDIO specifically
> > > ot document the reset line.
> > >
> > > Cc: Sean Wang <sean.wang@xxxxxxxxxxxx>
> > > Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> > > ---
> > >    .../bluetooth/mediatek,mt7921s-bluetooth.yaml | 49 +++++++++++++++++++
> > >    MAINTAINERS                                   |  1 +
> > >    2 files changed, 50 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..bbe240e7cc40
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7921s-bluetooth.yaml
> > > @@ -0,0 +1,49 @@
> > > +# 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
> > > +
> >
> > title:
> >
> > maintainers:
> >
> > description:
> >
> > ... and then, you missed
> >
> > allOf:
> >     - $ref: bluetooth-controller.yaml#
>
> (facepalm)
>
> > Everything else looks good.
> >
> > Cheers,
> > Angelo
> >
> > > +description:
> >
> > MT7921S is a (dual?) SDIO-attached dual-radio WiFi+Bluetooth combo chip;
> > this chip has two dedicated reset lines, one of which is used to reset
> > the Bluetooth core.
> > The WiFi part of this chip is described in ....where? :-)
>
> The function itself is fully probable and the implementation doesn't make
> use of the WiFi's reset line, so I don't see any reason to describe it?
> I don't actually know what the reset line does in the chip hardware.
> This patch is just described what is already used.
>
> > > +  This binding describes the Bluetooth side of the SDIO-attached MT7921S
> > > +  WiFi+Bluetooth combo chips. These chips are dual-radio chips supporting
> > > +  WiFi and Bluetooth. Bluetooth works over SDIO just like WiFi. Bluetooth
> > > +  has its own reset line, separate from WiFi, which can be used to reset
> > > +  the Bluetooth core.
> > > +
> > > +maintainers:
> > > +  - Sean Wang <sean.wang@xxxxxxxxxxxx>
> > > +
> > > +properties:
> > > +  compatible:
> > > +    enum:
> > > +      - mediatek,mt7921s-bluetooth
> > > +  reg:
> > > +    const: 2
> > > +
> > > +  reset-gpios:
> > > +    maxItems: 1
> > > +    description: A GPIO line connected to the Bluetooth subsystem reset line.
> > > +      Typically the W_DISABLE2# pin on M.2 E-key modules. If present this
> > > +      shall be flagged as active low.
> >
> > description:
> >     An active-low reset line connected for the Bluetooth core;
>
> connected to?

Eh yes, sorry - I edited that statement multiple times and that "for" stuck
there for reasons :-)

> >     on typical M.2 Key-E modules this is the W_DISABLE2# pin.
>
> Otherwise this looks better. Thanks.

You're welcome!

Cheers!

> ChenYu
>
> > Cheers,
> > Angelo
> >
> > > +
> > > +required:
> > > +  - compatible
> > > +  - reg
> > > +
> > > +additionalProperties: false
> > > +
> > > +examples:
> > > +  - |
> > > +    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 b64a64ca7916..662957146852 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -13657,6 +13657,7 @@ 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