Re: [PATCH v2 1/2] dt-bindings: net: bluetooth: nxp: Add support for 4M baudrate

From: Neeraj Sanjay Kale
Date: Wed Jun 18 2025 - 11:11:25 EST


Hi Paul,

Thank you for reviewing this patch.
>
> Am 18.06.25 um 16:20 schrieb Neeraj Sanjay Kale:
> > Add support for 4000000 as secondary baudrate.
>
> Could you specify how you tested this, that means, how did you set the
> speed, and then do the test, that it actually works at that speed.

The driver starts at fw-init-baudrate, and if this 'max-speed' baudrate is different, it sends a vendor command to the FW to switch to max-speed.
After this point, both driver and chip communicate over 4000000 baudrate.

I have verified this using Saleae Logic Analyzer, where we have to set the baudrate to decode the UART packets properly.

I can add these details in V3 driver patch.

>
> > Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@xxxxxxx>
> > ---
> > v2: Use the available 'max-speed' device tree property. (Krzysztof)
> > ---
> > .../devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git
> > a/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
> > b/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
> > index 3ab60c70286f..4a1b6ea48a2f 100644
> > ---
> > a/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
> > +++ b/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.y
> > +++ aml
> > @@ -34,6 +34,12 @@ properties:
> > This property depends on the module vendor's
> > configuration.
> >
> > + max-speed:
> > + enum:
> > + - 3000000
> > + - 4000000
> > + default: 3000000
> > +
> > firmware-name:
> > maxItems: 1
> >
> > @@ -78,6 +84,7 @@ examples:
> > bluetooth {
> > compatible = "nxp,88w8987-bt";
> > fw-init-baudrate = <3000000>;
> > + max-speed = <4000000>;
> > firmware-name = "uartuart8987_bt_v0.bin";
> > device-wakeup-gpios = <&gpio 11 GPIO_ACTIVE_HIGH>;
> > nxp,wakein-pin = /bits/ 8 <18>;

Thanks,
Neeraj